All Tools
Every tool on Codeswap, grouped by category — 816 in total and growing. Each one runs entirely in your browser: paste your data, get a result, and nothing is sent to a server. No signup, no API keys, no tracking of what you process. Jump to a category below or scroll the full list.
LLM Tools
101 tools →- OpenAI Token Counter Count tokens for GPT-4o, GPT-4, GPT-3.5, o1, o3 with cost estimates.
- Claude Token Counter Count tokens for Claude 3.5 Sonnet, Opus, Haiku, and Claude 4.x.
- Gemini Token Counter Count tokens for Gemini 1.5 Pro, Flash, and Gemini 2.x.
- LLM API Cost Calculator Estimate per-call and monthly costs across LLM providers.
- Multi-Model Token Comparison Compare token counts and costs across GPT, Claude, Gemini, Llama side by side.
- Embedding Cost Calculator Estimate embedding API costs across providers and dimensions.
- System Prompt Analyzer Analyze prompt length, structure, and estimated cost per call.
- Prompt Token Cost Calculator Compare what one prompt costs across every major model. Cached vs uncached pricing.
- ChatGPT / Claude Chat Exporter Format a ChatGPT or Claude conversation export as Markdown, JSON, or HTML.
- OpenAI Pricing Calculator Estimate OpenAI API cost for any GPT model. Per-call + monthly projection.
- Claude Pricing Calculator Estimate Anthropic Claude API cost. Opus / Sonnet / Haiku with prompt caching.
- DeepSeek Token Counter Count tokens for DeepSeek-V3 and DeepSeek-R1 with cost estimates.
- OpenAI Function / Tool Schema Builder Build OpenAI function-calling JSON schemas visually. Parameter types, descriptions, required.
- Anthropic Tool Definition Builder Build Anthropic Claude tool definitions visually. JSON schema + description.
- Recursive Text Chunker (RAG) Split long text into overlapping chunks for embeddings. Configurable size and overlap.
- Embedding Model Comparison Table Compare every major embedding model: dimensions, max input, price, MTEB score.
- Cosine Similarity Calculator Compute cosine similarity between two vectors. Paste embedding vectors, get the score.
- RAG Cost Estimator Estimate end-to-end RAG cost: embedding + storage + retrieval + LLM completion.
- Vector DB Pricing Calculator Compare Pinecone / Qdrant / Weaviate / pgvector for your vector count and queries.
- JSON Extractor from LLM Output Pull JSON objects out of mixed-content LLM responses (with code fences, prose, retries).
- Code Block Extractor Extract every fenced code block from Markdown / LLM output. Group by language.
- Prompt PII Redactor Redact emails, phone numbers, names, addresses from text before sending to an LLM.
- Prompt Injection Scanner Scan user input for common prompt-injection patterns: instruction overrides, jailbreaks.
- GPT-5 Token Counter Token counter dedicated to GPT-5 / GPT-5 Mini / Nano. Uses o200k_base tokenizer.
- GPT-4o Token Counter Token counter dedicated to GPT-4o. Uses o200k_base tokenizer.
- GPT-3.5 Token Counter Token counter dedicated to GPT-3.5 Turbo. Uses cl100k_base tokenizer.
- Llama Token Counter Estimate tokens & cost for Llama 3.1 / 3.3 (8B, 70B, 405B). 128K tiktoken vocab.
- Mistral Token Counter Estimate tokens & cost for Mistral Large, Small, Nemo & Codestral. Tekken tokenizer.
- Qwen Token Counter Estimate tokens & cost for Qwen2.5 (7B–72B & Coder). ~152K BPE vocab.
- Gemma Token Counter Estimate tokens & cost for Gemma 2 (27B, 9B, 2B). 256K vocab, 8K context.
- Grok Token Counter Estimate tokens & cost for xAI Grok 2, Grok 2 mini & Grok Beta. 131K window.
- LLM Context Window Comparison Compare context windows of GPT, Claude, Gemini, Llama & more. See how much text fits.
- AI Image Generation Cost Calculator Compare cost of DALL·E, GPT-image, Flux, Imagen & Stable Diffusion per image.
- Self-Hosting vs API Cost Calculator Compare self-hosting an open LLM on GPUs against per-token API pricing. Find break-even.
- Transformer Parameter Calculator Count LLM parameters from architecture: vocab, hidden size, layers, heads, GQA, FFN.
- LLM Training FLOPs Calculator Estimate training/inference FLOPs (6ND), GPU-hours, wall-clock time & cost.
- GPU Cloud Price Comparison Compare H100, A100, 4090 rental prices across AWS, Lambda, RunPod, Vast & more.
- Batch API & Caching Savings Calculator Calculate savings from the Batch API (50% off) and prompt caching for OpenAI, Claude, Gemini.
- Prompt Anonymizer — Replace Names & Entities Replace person names, company names, product codes with anonymous placeholders.
- Batch Prompt Formatter Apply one prompt template across CSV rows. Generates the batch as JSON for API calls.
- Prompt to Python Script Wrap a prompt into a runnable Python script (OpenAI / Anthropic SDK).
- Prompt to JavaScript / Node Script Wrap a prompt into a runnable Node script (OpenAI / Anthropic SDK).
- Prompt to cURL Wrap a prompt into a working cURL command for any major LLM API.
- Conversation Log Parser Parse any chat transcript into structured turns. Works with copy-pasted UIs.
- Multi-Shot to Single-Shot Converter Collapse a few-shot prompt with examples into one big single-shot prompt.
- Persona / Role Prompt Generator Build system prompts with expertise, tone, format, refusal patterns from a template.
- Negative Prompt Builder (Image Gen) Build negative prompts for Stable Diffusion / Midjourney / Flux from category tags.
- Output Schema → Prompt Instruction Convert a JSON Schema into the prompt text that asks an LLM to produce matching JSON.
- Prompt Diff — For Fine-Tuning Datasets Diff two prompts side-by-side. Highlight added/removed instructions, examples, tokens.
- Gemini Function Declaration Builder Build Gemini FunctionDeclaration JSON schemas. Compatible with Google AI Studio + Vertex.
- Embedding Dimension Calculator (Storage + Memory) Calculate storage and RAM for an embedding index by dimension and document count. Compare float32 vs int8 quantization.
- LLM Cost Comparator (Cross-Provider) Compare API cost across providers for the same input/output token count. OpenAI, Anthropic, Google, DeepSeek, Mistral.
- Tokens-per-Word Chart by Model Visualise how each tokenizer (GPT-4o, Claude, Gemini, Llama) splits English / multilingual text. Compare token efficiency.
- LLM Structured Output Validator (JSON Schema) Validate LLM responses against a JSON Schema. Catch missing fields, wrong types, format errors before sending to your application.
- Prompt Injection Tester (LLM Vulnerability Probe) Test an LLM prompt against 30+ known injection patterns. Helps harden system prompts before production.
- LLM VRAM Calculator Calculate the GPU VRAM needed to run any LLM at a given quantization and context length, and see which GPUs fit.
- GGUF VRAM & Size Calculator Estimate the file size and VRAM for any GGUF quant (Q2_K to Q8_0, F16) of a model, including KV cache.
- Chat Template Formatter Wrap a conversation into a model's exact prompt format — ChatML, Llama 3, Mistral, Gemma, Phi-3, Alpaca, Vicuna — with every special token shown.
- LLM Download Size Calculator Estimate an LLM download size from parameters and GGUF quant (Q4_K_M, Q8_0, F16) using real bits-per-weight.
- MergeKit Config Generator Generate a valid mergekit YAML for SLERP, TIES, DARE, linear, task-arithmetic or passthrough model merges.
- GGUF Metadata Reader Drop a .gguf file and read its header — architecture, context length, layers, quantization, tokenizer. Parsed in your browser, nothing uploaded.
- RoPE / YaRN Context Extension Calculator Work out the RoPE scaling factor to extend a model context (linear, dynamic-NTK, YaRN) and get the rope_scaling config for transformers.
- Tokens per Second Calculator Estimate LLM inference speed in tokens per second from your GPU memory bandwidth and the model size — the memory-bound limit.
- Stable Diffusion VRAM Calculator Estimate VRAM for Stable Diffusion, SDXL, and Flux image generation by model, precision, resolution, and batch size.
- LLM GPU Requirements Checker Check whether a specific LLM fits on your GPU at a chosen quantization and context, with offload and multi-GPU advice.
- KV Cache Size Calculator Calculate transformer KV cache memory from layers, heads, context length, batch size, and precision — the hidden VRAM cost of long context.
- LLM Fine-Tuning Cost Calculator Estimate the GPU-hours and dollar cost to fine-tune an LLM with LoRA, QLoRA, or full fine-tuning across cloud GPUs.
- Prompt Caching Savings Calculator Calculate how much prompt caching saves on Anthropic and OpenAI API bills given your cached tokens, hit rate, and request volume.
- Vision Token Calculator Calculate how many tokens an image costs on GPT-4o, Claude, and Gemini from its dimensions, plus the dollar cost.
- Ollama Modelfile Generator Build a valid Ollama Modelfile from a form — base model, system prompt, parameters, template, and stop tokens.
- ChatML Formatter Convert a conversation into ChatML with im_start and im_end tokens, the chat format used by many open models.
- Safetensors Metadata Viewer Inspect a .safetensors file header locally — tensor names, shapes, dtypes, and total parameter count — without uploading.
- LoRA Memory Calculator Estimate LoRA fine-tuning trainable parameters and adapter, gradient and optimizer memory from model dimensions, rank and target modules. GQA-aware, with presets.
- BLEU and ROUGE Calculator Compute BLEU-1 to BLEU-4 with brevity penalty and ROUGE-1/2/L precision, recall and F1 between a candidate and reference text. Runs in your browser.
- Confusion Matrix Calculator Build a confusion matrix from actual,predicted pairs with accuracy, per-class precision, recall and F1, plus macro, micro and weighted averages.
- Perplexity Calculator Calculate language-model perplexity from per-token log-probabilities, with cross-entropy in nats and bits. Supports natural-log, log2 and log10 inputs.
- MoE Active Parameters Calculator Work out total versus active per-token parameters of a Mixture-of-Experts model from expert count, top-k, params per expert and shared layers. Presets included.
- Transformer FLOPs Calculator Estimate transformer forward and training FLOPs from sequence length, dimension, layers, FFN size and vocab, with an attention versus MLP breakdown.
- LLM Sampling Visualizer See how temperature, top-k and top-p reshape a model next-token distribution. Enter logits and watch the probabilities sharpen, flatten and truncate live.
- Logprobs Visualizer Paste OpenAI-style logprobs JSON for a colour-coded confidence heatmap, per-token probabilities, perplexity and the lowest-confidence tokens.
- Fine-tuning JSONL Validator Validate a chat or prompt/completion JSONL fine-tuning dataset — JSON, roles, structure, duplicates, missing assistant turns — and estimate token count.
- OpenAI API Error Code Explainer Look up any OpenAI API error — 400, 401, 403, 429, 500, 503 and insufficient_quota — with the cause in plain English and the exact fix. Covers rate limits, context-length and auth errors.
- Anthropic / Claude API Error Explainer Decode Anthropic and Claude API errors — the difference between 429 rate_limit and 529 overloaded, plus 400, 401, 403, 413 and 500 — with the cause and the right retry or backoff.
- LLM SSE Stream Decoder Paste a raw Server-Sent Events stream from an LLM API and see each data: chunk parsed, deltas concatenated and the final assembled message. Handles OpenAI and Anthropic event formats.
- OpenAI Batch API JSONL Builder Build and validate a JSONL file for the OpenAI Batch API — one request per line with custom_id, method, url and body — and catch malformed lines before you upload.
- TPM / RPM Rate Limit Calculator Work out whether your workload fits an OpenAI or Anthropic tier — convert requests and tokens per minute into the TPM/RPM headroom you need, and find the concurrency that stays under the cap.
- ShareGPT ↔ OpenAI Dataset Converter Convert fine-tuning datasets between ShareGPT (conversations/from/value) and OpenAI (messages/role/content) formats, both directions, with role mapping and validation.
- Alpaca ↔ ChatML Dataset Converter Convert instruction-tuning data between Alpaca (instruction/input/output) and ChatML / OpenAI messages format, both directions, so the same dataset works across trainers.
- JSON Schema to GBNF Grammar Turn a JSON Schema into a GBNF grammar for llama.cpp and vLLM constrained decoding, so a local model is forced to emit valid structured JSON.
- Fine-Tuning JSONL Deduplicator De-duplicate a fine-tuning JSONL dataset — exact and normalized matching on the prompt/completion or messages — and report how many rows were removed.
- OpenAI logit_bias Builder Build an OpenAI logit_bias map from words or token IDs — ban or boost tokens — with a -100 to 100 slider, ready to paste into your API call.
- vLLM serve Command Generator Generate a vllm serve command from your model, GPU count, dtype, max-model-len and quantization — with tensor-parallel and the right flags filled in.
- MCP Tool Schema Validator Validate a Model Context Protocol tool definition — name, description and inputSchema — against the spec, and catch the JSON Schema mistakes that make a tool invisible to the model.
- LLM License & Commercial-Use Checker Check whether an open-weight model — Llama, Mistral, Qwen, DeepSeek, Gemma — is cleared for commercial use, and the catches (active-user caps, attribution, output restrictions).
- Assistants / Thread Cost Estimator Estimate the cost of an OpenAI Assistants or threaded conversation as message history grows — cumulative input tokens per turn quickly dominate the bill.
- pgvector Index Sizing Calculator Estimate the disk and RAM a pgvector index needs for N vectors at D dimensions — flat vs HNSW vs IVFFlat — so you can size Postgres before loading embeddings.
- Agent Loop Token Budget Estimator Estimate the token budget an agent loop burns — system prompt + tool schemas + growing scratchpad over K steps — and see where the multi-step cost comes from.
- LLM API Pricing Table Compare API pricing for GPT-4o, Claude, Gemini, Llama, DeepSeek, Mistral and more side by side — sort by input or output cost per million tokens and estimate your cost per call.
- Chinchilla Compute-Optimal Calculator Find the compute-optimal training tokens, FLOPs, and rough GPU cost for an LLM using the Chinchilla scaling laws — given a parameter count, a token budget, or a compute budget.
- Full Fine-Tuning VRAM Calculator Calculate the GPU memory a full fine-tune needs — weights, gradients, Adam optimizer states, and activations — and compare AdamW, 8-bit Adam, gradient checkpointing, and ZeRO sharding.
- Speculative Decoding Speedup Calculator Estimate the wall-clock speedup of speculative decoding from the draft acceptance rate, draft length, and draft-to-target cost ratio — and find the draft length that maximises throughput.
JSON
65 tools →- JSON Formatter & Validator Format, validate, and minify JSON. Strict and loose parsing modes.
- JSON to TypeScript Generate TypeScript interfaces from JSON with deep nested type inference.
- JSON to YAML Convert JSON to YAML and back, preserving order and comments.
- JSONPath Tester Test JSONPath expressions against your JSON, see matches highlighted.
- JSON Diff Compare two JSON documents structurally; see added, removed, and changed keys.
- JSON to CSV Convert JSON arrays to CSV. Handles nested objects via dotted-key flattening.
- CSV to JSON Convert CSV to JSON. Type-infer numbers and booleans, configurable delimiter.
- JSON Schema Generator Generate a JSON Schema (draft 2020-12) from a sample JSON document.
- JSON Tree Viewer Browse JSON as a collapsible tree. Click to copy any path or value.
- CSV Diff Compare two CSVs by row keys. See added, removed, changed rows.
- JSON ↔ XML Converter Convert JSON to XML and back. Handles attributes, arrays, nested objects.
- Mock JSON API Builder Generate realistic JSON API responses with pagination, ETag, headers.
- JSON to Zod Schema Generate Zod (z.object) validators from a JSON sample. TypeScript-ready.
- JSON to Pydantic Model Generate Pydantic v2 BaseModel classes from a JSON sample. Python-ready.
- YAML to JSON Converter Convert YAML to JSON quickly. Handles anchors, multi-document streams, scalars.
- JSON Schema Validator Validate JSON against a JSON Schema (draft 2020-12). Shows path of each violation.
- JSON to Go Struct Generate Go structs from a JSON sample. Includes json tags.
- JSON to Rust Struct (serde) Generate Rust structs with serde derive macros from JSON.
- JSON to Kotlin Data Class Generate Kotlin data classes (kotlinx.serialization) from JSON.
- JSON to Swift Codable Generate Swift Codable structs from JSON. Auto-handles nested types.
- JSON to Java POJO Generate Java POJOs with Jackson/Gson annotations from JSON.
- JSON to C# Class Generate C# classes with System.Text.Json attributes from JSON.
- JSON to PHP Class Generate PHP 8 classes from JSON. Typed properties, optional constructor promotion.
- JSON Merge Tool Deep-merge multiple JSON objects. Configurable strategies for arrays and conflicts.
- JSON Flattener / Unflattener Flatten nested JSON to dotted keys, or unflatten back.
- JSON to Query String Convert flat JSON to URL query string and back. RFC 3986 percent-encoding.
- JSON Schema to Example Data Generate example JSON that satisfies a JSON Schema. Useful for docs and tests.
- JSON to GraphQL Schema Generate a GraphQL SDL schema from a JSON sample.
- JSONL Viewer / Formatter View, validate, and reformat JSONL (newline-delimited JSON) files row by row.
- JSON Schema $ref Resolver Inline every $ref in a JSON Schema. Produces a self-contained flat schema.
- NDJSON to CSV Converter Convert newline-delimited JSON (one object per line) to CSV with a flat header row.
- JSON to BSON / Extended JSON Converter Convert standard JSON to MongoDB Extended JSON (BSON) and back. Handles ObjectId, Date, NumberLong.
- JSON5 to JSON Converter Strip JSON5 features (comments, trailing commas, unquoted keys) to produce strict JSON.
- JSONC to JSON (Strip Comments) Remove // and /* */ comments from JSONC (VS Code config files) to produce strict JSON.
- XML to JSON Converter Convert XML to JSON in your browser. Attribute / namespace handling, array detection.
- JSON Strict Validator (RFC 8259, Number Precision) Validate JSON against the strictest RFC 8259 rules. Flags trailing commas, comments, NaN, Infinity, precision loss.
- JSON Merge Patch (RFC 7396) Apply RFC 7396 JSON Merge Patch operations. Useful for PATCH endpoints that take partial updates.
- JSON Patch Builder (RFC 6902) Build and apply RFC 6902 JSON Patch operations. Visual diff between two JSON documents → patch operations.
- JSON Pointer Resolver (RFC 6901) Resolve a JSON Pointer against a JSON document. Path syntax /users/0/email returns the referenced value, with /-escape handling.
- JSON Visual Tree Explorer Render any JSON as a collapsible tree. Click to expand / collapse. Search by key or value. Browser-only.
- JSON Strict Prettifier (Sort Keys + Configurable Indent) Pretty-print JSON with optional sorted keys, configurable indent (2 / 4 / tab), and key ordering rules.
- JSON Array of Objects → CSV (Customizable Columns) Convert a JSON array of objects to CSV. Pick columns, reorder, rename. Handles nested objects via dot.notation flatten.
- JSON ↔ YAML ↔ TOML Roundtrip Converter Convert seamlessly between JSON, YAML, and TOML. Side-by-side three-pane editor. Edit any pane, others update.
- JSON + CSV Merger (Join by Key) Join a JSON array with a CSV file by a common key. Produces enriched JSON or CSV output.
- JSON Nested Array Flattener Flatten nested JSON arrays to a single-level array. Configurable depth, optional unique-only.
- JSON Comments Stripper (JSONC → JSON) Remove // and /* */ comments from JSONC files. Handles strings, escaped chars, nested comments correctly.
- JSON Property Counter (Deep Statistics) Count properties, depth, types in any JSON. Find which keys appear most across arrays of objects.
- JMESPath Tester Test JMESPath expressions against JSON live in your browser — the query language used by the AWS CLI --query flag.
- JSONata Tester (Playground) Run JSONata queries and transforms against JSON live — expressions, built-in functions, and output, in your browser.
- JSON to SQL Schema Infer a CREATE TABLE statement from JSON — column types detected across all records, with Postgres, MySQL, and SQLite dialects.
- JSON to .env Flatten a JSON object into .env variables — nested keys, arrays, case and prefix options, and shell-safe quoting. Runs in your browser.
- JSON Repair Fix broken JSON — trailing commas, single quotes, unquoted keys, comments, Python None/True/False, NaN, and unterminated strings. Shows every fix.
- Avro Schema from JSON Generator Generate an Apache Avro schema from sample JSON — infers field types, makes fields nullable with a union and default, widens mixed int and float to double, and handles nested records and arrays.
- JSON to SQL INSERT Generator Convert JSON to SQL INSERT statements — MySQL, PostgreSQL, SQLite or SQL Server, with correct identifier and string quoting, NULL and boolean handling, optional column list and multi-row batches.
- jq Playground (Run jq Filters Online) Run real jq filters against your JSON in the browser — the genuine jq processor compiled to WebAssembly. Pipes, select, map, group_by, @csv and all the usual flags. Nothing is uploaded.
- TypeScript to JSON Schema Convert TypeScript interfaces and type aliases into JSON Schema (draft 2020-12) — properties, required fields, unions and nested types resolved client-side.
- JSON to Ruby Converter Generate Ruby from a JSON sample — a Struct or attr_accessor class with typed fields, or a plain hash literal — inferred from the data you paste.
- JSON to Dart Converter Generate Dart classes from JSON for Flutter — typed fields plus fromJson / toJson methods, with nested objects and lists turned into their own classes.
- JSON to Scala Converter Generate Scala case classes from a JSON sample — typed fields with Option for nullable values and nested case classes for objects and arrays.
- JSON to Mongoose Schema Convert a JSON document into a Mongoose schema for MongoDB — inferred types, nested sub-schemas and arrays, ready to drop into a Node.js model.
- XML to CSV Converter Flatten repeating XML elements into CSV rows — pick the record element, get a column per child/attribute, with proper quoting for commas and quotes.
- CSV to XML Converter Convert CSV into XML — each row becomes a record element with a child or attribute per column, with configurable row and root element names.
- YAML to CSV Converter Convert a YAML list of objects into CSV — keys become the header row, with nested values flattened using dotted paths and safe quoting.
- CSV to YAML Converter Convert CSV into a clean YAML list of objects — typed scalars for numbers and booleans, with the header row mapped to keys on each record.
- JSON5 Viewer Parse and view JSON5 as a collapsible tree — comments, trailing commas, unquoted keys, single quotes and hex numbers all handled. Runs in your browser.
Regex
29 tools →- Regex Tester Test regular expressions against text. PCRE, JavaScript, and Python flavors.
- Regex Explainer Break down a regex into plain English. Explains each token, group, quantifier.
- Regex Cheatsheet Searchable reference of regex syntax: classes, quantifiers, lookarounds, flags.
- Regex from Examples Paste examples of strings to match; get a regex that matches them all.
- Regex Replace Tester (Live, with Capture Groups) Test regex find + replace with capture group references ($1, $&). Live preview, all flags.
- Regex Visualizer (Railroad Diagram) Render any regex as a railroad diagram. See alternations, character classes, quantifiers at a glance.
- Common Regex Library (Email, URL, IP, Phone, Date) Searchable library of validated regex patterns: email, URL, IPv4 / IPv6, phone, ZIP, hex color, ISBN, credit card. Copy with one click.
- Regex Flags Reference (i, g, m, s, u, y, x) What every regex flag does, side-by-side. JavaScript, Python, Perl, PCRE — differences highlighted.
- Regex Backreference Tester Test backreferences (\1, \k<name>) live. Helps debug palindrome / duplicate-word / matched-tag regexes.
- Build Regex from Example Strings Paste 2-20 example strings; get a regex that matches all of them (and only the patterns you intend). Generic→specific dial.
- Regex Anchors Tester (^, $, \b, \B) Test regex anchors interactively. See where ^, $, \b, \B match in your input. Multiline / single-line behavior.
- Regex Cheat Sheet by Language (JS, Python, PHP, Java, Go) Side-by-side regex syntax reference. Anchors, quantifiers, lookbehinds, named groups — how each language varies.
- Regex Character Class Builder ([abc], [a-z], [^...]) Visually build character classes. Pick ranges, individual chars, negation. Output the regex syntax.
- Regex Escape / Unescape Tool Escape special characters in a string so it works as a literal inside a regular expression. Unescape too.
- ReDoS Checker (Catastrophic Backtracking Detector) Paste a regex and detect catastrophic backtracking (ReDoS): static analysis of nested quantifiers plus a live in-browser timing probe. Runs locally.
- Regex String Generator (Reverse Regex) Generate example strings that match a regular expression — great for test data and understanding a pattern.
- Glob to Regex Converter Convert glob patterns (*.js, src/**/*.ts) into equivalent regular expressions. Bash and minimatch styles.
- Regex Lookahead & Lookbehind Tester Test regex lookahead and lookbehind assertions live. See what matches without the assertion being consumed.
- Regex Match Extractor Extract every match of a regex from text as a clean list. Pull emails, URLs, numbers, or any pattern out of logs.
- Regex Split Tester See how a regular expression splits a string into parts, just like String.split with a pattern.
- Regex Named Group Extractor Run a regex with named capture groups over text and extract each match as a JSON object and table.
- Regex Match Counter Count how many times a regex matches, list each match with its position, and tally distinct values.
- Word List to Regex Turn a list of words into one regex that matches any of them, with escaping and trie optimization.
- Regex Extract Matches Extract every regex match or a chosen capture group into a clean list, with optional dedupe, sort, and join.
- Regex Escape & Unescape Escape a literal string for safe use inside a regular expression, or unescape one back to plain text.
- Regex Line Filter — Browser grep Filter lines by a regex: keep matches, invert, show line numbers, or print only the matched part.
- Route Pattern to Regex Converter Convert route patterns like /users/:id and /posts/{slug} into a regex with capture groups, plus a live path tester.
- Regex Unicode Property Escapes Reference Reference for regex Unicode property escapes like \p{L} and \p{Script=Greek}, with a live match-highlighting tester.
- Regex Quantifier Reference & Demo Reference for regex quantifiers and greedy versus lazy matching, with a live demo that highlights matches.
Crypto & Hashing
64 tools →- JWT Decoder Decode, verify, and generate JWTs. HS256, RS256, ES256, EdDSA support.
- Hash Generator Generate MD5, SHA-1, SHA-256, SHA-512, BLAKE2 hashes in your browser.
- HMAC Generator Compute HMAC signatures with SHA-256, SHA-512, and other digests.
- UUID Generator Generate UUID v1, v4, v7. Bulk generation up to 1,000 at a time.
- JWT Generator Generate signed JWTs with HS256/HS384/HS512, RS256, ES256. Quick payload editor.
- Secure Password Generator Cryptographically random passwords with configurable length and character classes.
- Password Strength Checker Check password entropy and crack time. Browser-only — never sent anywhere.
- Credit Card / Luhn Validator Validate credit card numbers with the Luhn algorithm. Detect card brand. Browser-only.
- IBAN Validator Validate IBAN — format, country, mod-97 checksum.
- OAuth Scope Decoder Decode OAuth scope strings for Google, GitHub, Microsoft. See what each scope grants.
- Bcrypt Hash Generator & Verifier Generate and verify bcrypt password hashes. Configurable cost factor. Browser-only.
- BLAKE3 Hash Generator BLAKE3 — fast modern hash. 256-bit output, configurable length.
- PEM ↔ DER Converter Convert X.509 certificates and keys between PEM (Base64) and DER (binary).
- Test Credit Card Number Generator (Luhn-Valid) Generate Luhn-valid test card numbers for development. Visa, Mastercard, Amex test BINs. Sandbox only.
- File Hash Calculator (SHA-256, SHA-1, MD5) Drop a file, get SHA-256 / SHA-512 / SHA-1 / MD5 hashes calculated in your browser. Verify downloads against published checksums.
- Password Leak Check (Pwned Passwords API) Check if a password appears in known data breaches using HaveIBeenPwned k-anonymity API. Password never leaves browser.
- RSA Keypair Generator (2048 / 4096-bit) Generate RSA public + private keypair in PEM format. WebCrypto, runs in browser, never sent anywhere.
- Ed25519 Keypair Generator Generate an Ed25519 public + private keypair. Modern, fast, used by SSH / GPG / JWT EdDSA.
- SSH Public Key Fingerprint Calculator Calculate the SHA-256 fingerprint of an SSH public key. Matches ssh-keygen output.
- UUIDv7 Generator (Time-Ordered) Generate UUIDv7s — time-ordered UUIDs ideal for database primary keys. Sortable, distributed-friendly.
- TOTP / 2FA Code Generator (RFC 6238) Generate TOTP 6-digit codes from a base32 secret. Live updating, like Google Authenticator. Browser-only.
- SWIFT / BIC Code Validator Validate SWIFT / BIC bank codes. Decodes bank, country, and branch.
- Test IBAN Generator (Mod-97 Valid) Generate Mod-97-valid test IBANs for development. 30+ country formats. Sandbox use only.
- WebAuthn Passkey Tester (Register + Verify) Test WebAuthn / passkey registration and assertion in your browser. No backend needed.
- UUID Validator (v1–v8, Detect Version) Validate any UUID. Detects version (1, 3, 4, 5, 6, 7, 8) and variant. Decodes timestamps from v1 / v6 / v7.
- Password Policy Builder (Regex Generator) Visually build a password policy (min length, uppercase, digit, symbol, no spaces). Generates regex, JS, and HTML pattern attribute.
- JWT Builder + Signer (HS256, RS256) Build and sign a JWT in your browser. HS256 (HMAC), RS256 (RSA). Specify header, claims, secret / private key.
- AES-GCM Encrypt / Decrypt Tool Encrypt and decrypt with AES-256-GCM in your browser. PBKDF2 password-derived keys. WebCrypto-based, secure.
- HMAC Signature Verifier (Webhooks: Stripe, GitHub, Slack) Verify HMAC-SHA256 signatures on webhook payloads. Supports Stripe / GitHub / Slack signing formats.
- JWT + JWKS Verifier (Public Key Discovery) Verify a JWT against a JWKS endpoint URL. Fetches public key, validates signature, decodes claims.
- Ed25519 Sign + Verify (Message Authentication) Sign and verify messages with Ed25519. Generate keypair, sign, verify against public key. WebCrypto.
- UUID to Base62 (Short ID) Converter Convert UUIDs to compact base62 strings (Bitly-style short IDs) and back. 22 chars vs 36.
- CRC32 Checksum Calculator Compute the CRC32 checksum of text in hex and decimal. Matches zip/gzip/PNG CRC32 (IEEE polynomial).
- NanoID Generator Generate URL-safe NanoIDs in bulk. Custom length and alphabet; cryptographically random via WebCrypto.
- Snowflake ID Decoder (Twitter/Discord) Decode Twitter/Discord Snowflake IDs into timestamp, worker, process, and sequence components.
- CRC-16 Calculator (Modbus, CCITT, XMODEM) Compute CRC-16 across common variants — ARC, Modbus, CCITT-FALSE, XMODEM, Kermit — in hex and decimal.
- Adler-32 Checksum Calculator Compute the Adler-32 checksum used in zlib and PNG, in hex and decimal, with its two component sums.
- FNV Hash Calculator (FNV-1 / FNV-1a) Compute the FNV-1 and FNV-1a non-cryptographic hash in 32-bit and 64-bit, in hex and decimal.
- CRC-8 Calculator — All Common Variants Compute CRC-8 across eight variants — SMBus, Maxim/1-Wire, DVB-S2, CDMA2000, ROHC, WCDMA — in hex and decimal.
- Fletcher Checksum Calculator Compute the Fletcher-16 and Fletcher-32 checksums of text or hex, with both running sums, in hex and decimal.
- Internet Checksum Calculator (RFC 1071) Compute the 16-bit one's-complement Internet checksum from RFC 1071, used in IPv4, ICMP, TCP, and UDP.
- CRC-64 Calculator (XZ, ECMA-182, ISO) Compute the CRC-64 checksum across the XZ, ECMA-182, and GO-ISO variants of text or hex, in hex and decimal.
- MurmurHash3 Calculator (32-bit) Compute the MurmurHash3 x86 32-bit non-cryptographic hash of text with an optional seed, in hex and decimal.
- djb2 Hash Calculator (djb2, sdbm, Java) Compute the djb2, djb2a, sdbm, and Java String.hashCode non-cryptographic hashes of text, in hex and decimal.
- ULID Generator Generate ULIDs — 128-bit, lexicographically sortable, Crockford base32 identifiers — and decode their timestamp.
- htpasswd Generator Generate Apache and Nginx .htpasswd entries with bcrypt, APR1-MD5, or SHA-1 — entirely in your browser.
- Basic Auth Header Generator Build an HTTP Authorization: Basic header from a username and password (base64), and decode one back.
- X.509 Certificate Decoder Decode a PEM X.509 certificate locally — subject, issuer, validity, SANs, key, serial, and fingerprints — no upload.
- JWKS Generator Generate a JSON Web Key Set with a fresh RSA or EC key pair, a kid thumbprint, and the matching private key.
- JWK to PEM Converter Convert keys between JWK and PEM in both directions for RSA and EC, auto-detecting the input. Uses the browser Web Crypto API — keys never leave your machine.
- ECDSA Key Generator Generate an elliptic-curve (ECDSA) key pair — P-256, P-384 or P-521 — as PEM or JWK in your browser with Web Crypto. The private key never leaves your machine.
- JWT Secret Generator Generate a cryptographically strong random secret for HS256, HS384 or HS512 JWT signing, output as hex, base64 and base64url, sized to the algorithm.
- UUID v5 Generator Generate deterministic, name-based UUID v5 (SHA-1) identifiers from a namespace and a name. Built-in DNS, URL, OID and X.500 namespaces or your own.
- Snowflake ID Generator Generate Twitter/Discord-style 64-bit Snowflake IDs packing a millisecond timestamp, machine ID and sequence, with the bit breakdown and choice of epoch.
- ASN.1 / DER Decoder Decode ASN.1 DER structures — certificates, CSRs, keys, signatures — from PEM, base64 or hex into a readable tag/length/value tree with OIDs resolved to names.
- Diceware Passphrase Generator Generate strong, memorable Diceware-style passphrases from a built-in word list with a secure random source. Choose word count and separator and see the entropy.
- CSR Generator (Certificate Signing Request) Generate a PKCS#10 Certificate Signing Request and matching private key in your browser — RSA or ECDSA, full distinguished name and Subject Alternative Names (DNS and IP). WebCrypto, nothing uploaded.
- Self-Signed Certificate Generator Generate a self-signed X.509 certificate and private key in your browser — RSA or ECDSA, Subject Alternative Names, CA or server profile and the standard v3 extensions. WebCrypto, nothing uploaded.
- DKIM DNS Record Generator Generate the DNS TXT record for a DKIM public key — paste your selector and key, get the v=DKIM1 record split correctly for publishing.
- CSR Decoder Decode a PKCS#10 Certificate Signing Request in your browser — see the subject, key type and size, and the Subject Alternative Names. Nothing is uploaded.
- SRI Hash Generator Generate a Subresource Integrity (SRI) hash for a script or stylesheet — sha256/384/512 — so the browser blocks a tampered CDN file. Computed locally.
- PEM Viewer Decode a PEM block — certificate, key, CSR or CRL — and read its ASN.1 structure as a labelled tree. Base64 to DER parsed entirely in your browser.
- ASN.1 Viewer Decode ASN.1 DER or BER from PEM, base64 or hex and read the full tag/length/value tree with resolved OIDs and byte offsets. In your browser.
- CSR Viewer Decode a PKCS#10 certificate signing request and read its subject, public key, requested SANs and signature algorithm. Parsed in your browser — keys stay local.
Encoding
42 tools →- Base64 Encoder / Decoder Encode and decode Base64 text and files. URL-safe variant supported.
- URL Encoder / Decoder Percent-encode and decode URLs and query strings.
- HTML Entity Converter Encode and decode HTML entities. Named and numeric entities supported.
- Image to Base64 (Data URI) Convert any image to a base64 data: URI for embedding in HTML/CSS/JSON.
- String Escape / Unescape Escape strings for JSON, JavaScript, HTML, SQL, RegEx, shell. Unescape too.
- Caesar Cipher / ROT13 Encode and decode with Caesar cipher. ROT13 default; configurable shift.
- Base32 Encoder / Decoder RFC 4648 Base32 encoding (used in TOTP secrets, file hashes).
- Base58 Encoder / Decoder Base58 encoding (Bitcoin addresses, IPFS CIDs).
- Number Base Converter Convert numbers between binary, octal, decimal, hex, custom bases 2-36.
- Roman Numeral Converter Convert between Arabic numbers and Roman numerals (1 to 3,999,999).
- Text to Binary / Binary to Text Converter Convert text to 8-bit binary and back. ASCII or UTF-8 modes. Useful for puzzles and teaching.
- Morse Code Translator (Audio Playback) Convert text to Morse code and back. Plays audio at adjustable WPM. International alphabet.
- Hex String Converter — Text, Bytes, Colors, Endian Convert hex strings to text, byte arrays, decimal, binary; swap endianness; XOR; chunk.
- Base64 Image Viewer / Decoder Decode any base64 data URL to a preview image. Save as PNG / JPG / WebP. Inspect file size and dimensions.
- URL Percent Decoder (Multi-Pass) Decode URL-encoded strings, handling double / triple encoding automatically. RFC 3986 compliant.
- ROT13 / ROT47 / Atbash Cipher Encode and decode with ROT13, ROT47, and Atbash ciphers. Live preview, paste-friendly.
- Base91 Encoder / Decoder Encode and decode with basE91 — denser than base64 (~13% smaller).
- HTML Entity Encoder + Decoder Encode / decode HTML entities (&, ', ', named entities). Handles numeric, hex, and named. Browser-only.
- Punycode (IDN) Encoder + Decoder Convert internationalized domain names to / from Punycode (xn--…). Detect homograph attacks.
- Quoted-Printable Encoder + Decoder Encode / decode quoted-printable (RFC 2045) used in email MIME bodies. Handles soft line breaks correctly.
- Base32hex Encoder + Decoder (RFC 4648) Encode / decode base32hex (extended hex alphabet variant). Used by DNS NSEC3 records and other lex-sortable contexts.
- Base85 / Ascii85 Encoder + Decoder Encode / decode with Ascii85 (Adobe PostScript / PDF) variant. Denser than base64.
- Base62 Encoder + Decoder (URL Shorteners) Encode integers to base62 (0-9, a-z, A-Z). Used by URL shorteners for compact IDs. Both directions.
- MIME Base64 Encoder (Email Lines, 76 chars) Encode to base64 with MIME-style line breaks (every 76 chars). Required for email message MIME bodies.
- Vigenère Cipher Encoder + Decoder Encrypt and decrypt with the Vigenère cipher (keyed Caesar). Classic 16th-century polyalphabetic cipher.
- Rail Fence Cipher Encoder + Decoder Zigzag transposition cipher. Classic puzzle / CTF cipher. Choose number of rails.
- UTF-8 Byte Counter Count UTF-8 bytes vs characters in any text. See per-character byte sizes and spot multi-byte characters.
- XOR Cipher Tool Encrypt and decrypt text with a repeating-key XOR cipher. Hex and Base64 output; fully reversible.
- Atbash Cipher Encoder / Decoder Encode and decode the Atbash substitution cipher (A to Z, B to Y). Symmetric — the same step reverses it.
- Base64URL Encoder / Decoder Encode and decode Base64URL — the URL-safe Base64 variant used in JWT and web tokens. No padding, - and _.
- Unicode Escape Converter Convert text to and from \uXXXX unicode escapes (JavaScript, JSON, Java, Python styles). Reveal hidden characters.
- Bacon Cipher Encoder / Decoder Encode and decode Bacon's cipher, which hides each letter as a five-symbol A/B pattern. Classic steganography.
- Ascii85 / Base85 Encoder & Decoder Encode and decode Ascii85 (Base85) in Adobe and plain variants. More compact than Base64.
- ROT47 Encoder & Decoder Apply ROT47, a rotation cipher over all 94 printable ASCII characters. Its own inverse, with a slider.
- Base45 Encoder & Decoder (RFC 9285) Encode and decode Base45 per RFC 9285 — the QR-friendly encoding used by EU COVID certificates.
- Quoted-Printable Encoder & Decoder Encode text to MIME Quoted-Printable or decode it back, with UTF-8, =XX escapes, and soft line breaks.
- Base62 Encoder & Decoder Encode text or a large integer to Base62 (0-9, A-Z, a-z) and back — the compact form used for short IDs.
- Z85 Encoder & Decoder (ZeroMQ) Encode binary or text to Z85, the ZeroMQ base-85 encoding (RFC 32), and decode it back.
- Base36 Encoder & Decoder Encode text or a large integer to Base36 (0-9, a-z) and decode it back — the compact alphanumeric encoding.
- Uuencode Encoder & Decoder Encode text or hex to classic Unix uuencode with begin/end framing, or decode a uuencoded block back to data.
- Hex Viewer View text or a file as a classic hex dump — offset, hex bytes and ASCII side by side, with byte count and encoding detail. Runs in your browser.
- Data URI Viewer Decode a data: URI and inspect it — media type, charset, base64 flag, decoded size and a live preview for images, fonts and text. In your browser.
Text Processing
52 tools →- Text Diff Compare two text blocks line by line. Word-level highlighting.
- Case Converter Convert text to camelCase, snake_case, kebab-case, PascalCase, SCREAMING_SNAKE.
- Word & Character Counter Count words, characters, sentences, paragraphs, reading time.
- Lorem Ipsum Generator Generate lorem ipsum or developer-themed placeholder text by paragraph, word, or list count.
- Random Data Generator Generate fake names, emails, phones, addresses, companies. Output JSON or CSV.
- Unicode Inspector Inspect every code point in a string. Block, category, name, hex, decimal.
- ASCII Art Text Generator Convert text to ASCII art with figlet-style fonts. Download as text.
- Random String Generator Generate random strings with custom character set, length, count. Cryptographically random.
- Name Generator (Person, Business, Fantasy) Generate realistic-sounding names: people (40+ cultures), businesses, fantasy characters.
- Fake Data Generator (Users, Addresses, Cards) Generate realistic fake data for testing: users, addresses, emails, phones, test credit cards.
- ASCII Table — Decimal, Hex, Binary, HTML Entity Full ASCII table (0-127) and extended (128-255). Lookup by char, decimal, hex, or HTML entity.
- Unicode Character Explorer Search Unicode by name, code point, or block. 150,000+ characters indexed.
- Advanced Text Statistics (Reading Time, Keyword Density) Beyond word count: reading time, syllable count, Flesch reading ease, keyword density, most-common words.
- Reverse Text / Upside-Down Text Generator Reverse characters, words, lines, or generate upside-down Unicode text for social bio fun.
- Text Compressor (gzip / deflate) Compress text in your browser with gzip / deflate / brotli. See exact byte savings, output as base64.
- Text Shuffler (Words, Lines, Characters) Randomly shuffle words, lines, or characters in text. Seed-reproducible for testing.
- Anagram Finder & Solver Find anagrams of any word. Sub-anagrams (use any subset of letters).
- Byte Size Formatter (KB / KiB / MB / MiB) Convert bytes between SI (KB, MB, GB) and binary (KiB, MiB, GiB). Parse human strings back into bytes. Decimal precision control.
- Jaccard Similarity Calculator (Text + Sets) Compute Jaccard similarity / distance between two strings (word, character, or n-gram tokenization).
- Levenshtein Edit Distance Calculator (with Operations Trace) Compute Levenshtein edit distance between two strings. Shows the actual edit operations (insert / delete / substitute).
- Word Frequency Counter (Top N Words) Count word frequency in any text. Top-N table, stopword filtering, n-gram mode (bigrams / trigrams).
- Extract URLs, Emails, Phones from Text Bulk-extract URLs, email addresses, and phone numbers from any text. Deduplicates and validates each.
- Emoji Finder + Copy (Search 4000+ Emoji) Search 4000+ emoji by name, keyword, or category. Click to copy. Codepoint + shortcode displayed.
- Number Format Converter (Locale + Scientific) Format numbers with locale separators (1,234.56 vs 1.234,56 vs 1 234,56), scientific notation, currency, ordinal.
- Shell Brace Expansion Expander Expand bash-style brace expressions like {a,b,c}, file.{txt,md}, img-{01..10}.png. Preview results.
- Number to Words Converter (English, Spanish, French, German) Convert numbers to spelled-out words. English, Spanish, French, German. Handles cardinal, ordinal, and currency.
- Words to Number Parser ("two thousand twenty-four" → 2024) Parse spelled-out English numbers into integers. Handles "one hundred and twenty-three", "two million five hundred", ordinals.
- Unicode Normalizer (NFC, NFD, NFKC, NFKD) Normalize Unicode strings between NFC / NFD / NFKC / NFKD forms. Compare composed vs decomposed accents, compatibility forms.
- Add Line Numbers to Text Prepend line numbers to any text. Configurable padding, starting number, separator. Strip numbers back.
- ASCII Art Text Generator (Figlet Fonts) Convert text to ASCII art in 5+ figlet-style fonts. Block letters, banners, fancy headers for README files.
- Word Counter Pro (Real-Time, Detailed Stats) Live word / character / paragraph / sentence count. Plus reading time, speaking time, longest word.
- Letter Frequency Analyzer (English, German, French, Spanish) Count letter frequency in text. Compare to English / German / French / Spanish baselines. Useful for cryptanalysis.
- Readability Score Calculator (Flesch, Gunning Fog, SMOG) Score text readability: Flesch-Kincaid, Gunning Fog, SMOG, Coleman-Liau. Grade level + reading ease.
- Trim Whitespace (Leading, Trailing, Multiple Spaces) Trim leading / trailing whitespace per line, collapse multiple spaces, remove blank lines. Configurable.
- Sort Lines Alphabetically (Or by Length, Number) Sort lines: alphabetical, length, numeric, reverse. Case-sensitive option. Deduplicate.
- Deduplicate Lines (Remove Duplicates from Text) Remove duplicate lines. Preserves order or sorts. Case-sensitive option.
- Character Count by Line (Find Longest, Shortest) Show character count per line. Find longest / shortest lines. Useful for code line-length audits.
- Extract Numbers from Text Pull out every number from text. Integers, decimals, percentages, currency, with negatives. Deduplicates and sorts.
- Extract Domains from Text (eTLD+1) Extract unique domains from URLs in text. Group by eTLD+1 (example.com from sub.example.com).
- Extract @ Handles / # Hashtags from Text Pull out @mentions and #hashtags from text. Twitter / Slack / Discord syntax.
- UTF-8 Validator + Sequence Inspector Validate UTF-8 byte sequences. Flag invalid sequences, overlong encodings, surrogates. Show byte-by-byte breakdown.
- File Encoding Detector (UTF-8, UTF-16, BOM) Detect file encoding from a binary upload. UTF-8, UTF-16 BE/LE, BOM detection, ASCII vs Latin-1.
- Line Ending Converter (CRLF, LF, CR) Convert between Windows CRLF, Unix LF, and classic Mac CR line endings. Show byte-level diff.
- Tab ↔ Space Converter (Configurable Width) Convert tabs to spaces or vice versa with configurable tab width. Preserves alignment.
- Compare Two Lists Compare two lists line by line — find items only in A, only in B and in both, with optional case-insensitive matching, whitespace trimming and sorted output, plus union and intersection counts.
- List / Column Transpose Tool Transpose rows and columns of delimited text — swap a grid so rows become columns, with auto-detected or chosen input delimiter, a separate output delimiter and ragged-row padding.
- TF-IDF Keyword Extractor Extract the terms that characterize a document with TF-IDF and n-grams — paste text, get the weighted keywords and phrases search engines key on. Runs locally.
- Keyword Density Checker Check keyword density and word count for content — single words and 2-3 word phrases, with stop-words filtered — to spot under- or over-optimization.
- BBCode Viewer Paste BBCode and preview the rendered result — bold, italic, lists, quotes, code, links and images, with URLs sanitized. Converted in your browser.
- RTF Viewer Open an RTF document and read it as plain text or a formatted preview — bold, italic, underline, unicode and CP1252 bytes decoded. Parsed in your browser.
- SRT Subtitle Viewer Open an .srt subtitle file and read every cue with its start, end and duration — flags overlaps and bad timings. Parsed in your browser.
- WebVTT Viewer Open a WebVTT .vtt caption file and read every cue with timings, settings and NOTE or STYLE blocks — flags overlaps and a missing header. In your browser.
Code Conversion
106 tools →- cURL Converter Convert cURL commands to Python (requests/httpx), JavaScript (fetch), Go, and PHP.
- SQL Formatter Format SQL queries. Standard, T-SQL, PL/SQL, MySQL, PostgreSQL dialects.
- HTML Formatter / Beautifier Format and prettify HTML. Configurable indent, attribute wrapping.
- CSS Formatter / Beautifier Format CSS. Sort properties alphabetically, normalize colors and units.
- XML Formatter & Validator Format and validate XML. Configurable indent. Catches well-formedness errors.
- JavaScript Beautifier / Minifier Format or minify JavaScript. Handles modern syntax (ES2023+, JSX, TypeScript).
- GraphQL Query Formatter Format GraphQL queries, mutations, and SDL schemas.
- TOML ↔ JSON Converter Convert TOML to JSON and back. Useful for Cargo.toml, pyproject.toml, config files.
- Stack Trace Beautifier Format and demangle stack traces. JavaScript, Python, Java, Go.
- NPM Package Size Estimator Estimate bundled size of any npm package using bundlephobia.
- YAML to .env Converter Convert nested YAML to flat .env. UPPER_SNAKE keys with dotted-path naming.
- JWT from cURL Composer Generate a cURL command with a freshly signed JWT in the Authorization header.
- package.json Validator Validate package.json structure, required fields, common mistakes.
- cURL to Python requests Convert cURL commands specifically to Python requests / httpx code.
- cURL to JavaScript fetch Convert cURL commands specifically to JavaScript fetch() code.
- cURL to OpenAI SDK Convert OpenAI cURL examples to OpenAI Python/Node SDK code.
- cURL to Anthropic SDK Convert Anthropic cURL examples to Anthropic Python/Node SDK code.
- Tailwind Class Sorter Sort Tailwind utility classes in the canonical order (matches the official Prettier plugin).
- YAML to TOML Converter Convert YAML config to TOML and back. Useful for moving between pyproject.toml and conda env files.
- INI to JSON Converter Parse INI / config files to JSON and back. Handles sections, comments, multi-value keys.
- Java .properties to YAML Converter Convert Java / Spring .properties files to YAML (and back). Dotted keys become nested maps.
- TSV ↔ CSV Converter Convert tab-separated values to comma-separated values, with proper RFC 4180 quoting.
- JSON to Protobuf (.proto) Schema Generate a Protocol Buffers .proto schema from a JSON sample. Infers types and message shape.
- CSV Column Extractor / Reorder Pick, drop, or reorder columns in a CSV without spreadsheets. Streams large files in browser.
- CSV Deduplicator Remove duplicate rows from a CSV based on selected columns. Configurable case/trim handling.
- .env to YAML / Docker Compose Env Converter Convert .env files to YAML (Kubernetes-style env list or map) and back.
- CSS Minifier Minify CSS in your browser. Removes comments, whitespace, and shortens hex colors. Source-map friendly.
- JavaScript Minifier Minify JS / mangle identifiers in your browser using Terser. Drop console.* in production builds.
- HTML Minifier Minify HTML in your browser. Collapses whitespace, removes optional tags, inline-minifies CSS / JS.
- CSV to SQL INSERT Generator Convert CSV to INSERT statements for MySQL, Postgres, SQLite, SQL Server. Custom table / column mapping.
- SQL INSERT to JSON Converter Parse a SQL INSERT statement (or many) back into JSON rows. MySQL / Postgres / SQLite syntax.
- XML Validator (Well-Formed Check) Validate XML for well-formedness. Pinpoints line / column of any parse error.
- MongoDB Query Builder (Visual) Build MongoDB find() and aggregation pipelines visually. Generates valid query JSON.
- Redis Command Reference (Searchable) Searchable reference of 240+ Redis commands with syntax, complexity, and examples.
- Open Source License Generator (MIT, Apache, GPL, BSD) Generate a LICENSE file with your name and year. MIT, Apache 2.0, GPLv3, BSD, ISC, MPL, Unlicense.
- Conventional Commit Message Builder Build properly-formatted Conventional Commit messages with type, scope, description, body, breaking flag.
- Semver Bumper (Calculate Next Version) Calculate the next semantic version from current version + change type. Major / minor / patch / pre-release.
- Postgres EXPLAIN Output Formatter Parse Postgres EXPLAIN / EXPLAIN ANALYZE output. Highlight slow nodes, sequential scans, sort spills.
- CSV Pivot Table Builder Pivot CSV by row / column / aggregate. Sum, count, average, min, max. Browser-only, no upload.
- CSV Splitter (By Rows or Column Value) Split a large CSV into multiple files by row count or grouped by a column value. Download as ZIP.
- TAR Archive Builder (Browser-Only) Build a POSIX tar archive in your browser from drag-dropped files. Optional gzip. Useful for Docker COPY / config bundles.
- HTML Prettifier (Indent, Format) Format / beautify HTML. Configurable indent. Handles inline + block elements correctly.
- SQL Prettifier (Indent, Keywords Uppercase) Format SQL queries. Newlines before keywords, indent subqueries, uppercase keywords.
- GraphQL Query Prettifier Format GraphQL queries and schemas. Consistent indentation, field grouping.
- JSX / TSX Prettifier Format JSX / TSX. Self-closing tags, attribute wrapping, consistent indentation.
- TSV to JSON Converter Convert tab-separated values to JSON array of objects. Uses first row as headers.
- CSS Selector Tester (Live HTML Match) Test CSS selectors against any HTML snippet. Highlights matched elements live.
- XPath Tester (Live XML / HTML) Test XPath 1.0 expressions against any XML or HTML snippet. Highlights matched nodes.
- HTML Table to CSV Converter Paste HTML containing a <table>. Extract all rows as CSV. Handles colspan / rowspan / nested tables.
- HTML Table to JSON Converter Paste HTML containing a <table>. Extract as JSON array of objects, first row as keys.
- XML Prettifier (Indent + Format) Format / beautify XML. Configurable indent width. Preserves CDATA and comments.
- JSONL / NDJSON ↔ JSON Array Converter Convert between JSON Lines (NDJSON) and a JSON array. Used by streaming APIs, log files, OpenAI fine-tuning.
- Protobuf Wire Decoder Decode raw Protocol Buffers wire-format bytes from hex or base64 without a .proto — field numbers, wire types, and values.
- OpenAPI to TypeScript Generate TypeScript interfaces and types from an OpenAPI or Swagger spec — schemas, enums, $ref, allOf/oneOf, and nullable handled. JSON or YAML.
- GraphQL to TypeScript Convert a GraphQL SDL schema into TypeScript interfaces, types, and enums — objects, inputs, interfaces, unions, and scalar mapping included.
- Swagger to Postman Collection Convert an OpenAPI or Swagger spec into a Postman Collection v2.1 — requests, headers, query params, and example bodies grouped by tag.
- OpenAPI to Markdown Docs Turn an OpenAPI or Swagger spec into clean Markdown API docs — endpoints, parameters, request bodies, and response tables. JSON or YAML.
- CSV Viewer View CSV data as a sortable, filterable table — auto-detects the delimiter, handles quoted fields and embedded newlines. Runs in your browser.
- OpenAPI Diff Compare two OpenAPI or Swagger specs and classify every change as breaking, non-breaking, or informational — operations, params, responses, schemas.
- Tailwind to CSS Convert Tailwind utility classes to plain CSS — full default theme, with responsive, hover/focus and dark-mode variants expanded into media queries and pseudo-classes.
- SVG to JSX Convert SVG markup to a React JSX component — camelCases attributes, converts inline styles to objects, and wraps it as a function or arrow component.
- Bitwise Calculator Compute AND, OR, XOR, NOT, NAND, NOR, XNOR and bit shifts on 8/16/32/64-bit integers — results in binary, hex, octal and decimal. BigInt accurate.
- CSV Schema Inference Tool Infer a schema from CSV — detects column types, nullability, distinct counts and candidate keys, and exports a PostgreSQL CREATE TABLE, a TypeScript interface or a JSON Schema.
- GraphQL Schema to JSON Schema Converter Convert GraphQL SDL to JSON Schema — maps types, inputs, interfaces, enums and unions to $defs, models non-null vs nullable correctly, turns lists into arrays and lets you pick a root type.
- .env to JSON Converter Convert a .env file to JSON — strips export and comments, unquotes values, optionally coerces booleans numbers and null, lower-cases keys, and nests on double-underscore or dot.
- Parquet Viewer (Read .parquet Files) Open and inspect Apache Parquet files in your browser — schema, column types, row and row-group counts, compression codec, and a preview table of the rows. Export preview as CSV or JSON. Nothing uploaded.
- SQLite Viewer (Open .sqlite / .db Files) Open a SQLite database file in your browser — browse tables and views, inspect each table's schema, and run real SQL queries against an in-memory copy. Export query results as CSV. Nothing uploaded.
- Prisma Schema to SQL DDL Convert a Prisma schema into SQL CREATE TABLE DDL — models become tables, relations become foreign keys, enums and @unique / @@index carried over — for Postgres or MySQL.
- Prisma to Drizzle Converter Convert a Prisma schema into a Drizzle ORM TypeScript schema — tables, columns, types, relations and indexes — to migrate stacks without retyping it.
- SQL to SQLAlchemy Models Convert SQL CREATE TABLE statements into SQLAlchemy models — declarative classes with columns, types, primary and foreign keys and relationships.
- SQL to TypeORM Entities Convert SQL CREATE TABLE statements into TypeORM entities — decorated classes with @Column, @PrimaryGeneratedColumn and relations.
- SQL to Sequelize Models Convert SQL CREATE TABLE statements into Sequelize models — sequelize.define with attribute types, allowNull and keys.
- SQL to Drizzle Schema Convert SQL CREATE TABLE statements into a Drizzle ORM schema — pgTable / mysqlTable with typed columns, defaults and indexes.
- Database Connection String Parser Parse a database connection string — Postgres, MySQL, MongoDB, Redis — into host, port, user, database and every query option, and rebuild it. Done locally.
- JDBC URL Builder & Parser Build and parse a JDBC URL for Postgres, MySQL, SQL Server or Oracle — host, port, database and properties — with the right driver syntax for each.
- DATABASE_URL Splitter Split a DATABASE_URL into the discrete .env variables — DB_HOST, DB_PORT, DB_USER, DB_PASS, DB_NAME — and recombine them, for frameworks that want one or the other.
- SQL IN () Clause Builder Turn a pasted list — one per line, CSV or column — into a SQL IN (...) clause with correct quoting for strings or numbers, ready to drop into a query.
- DBML to SQL Converter Convert DBML (Database Markup Language) into SQL CREATE TABLE DDL — tables, references and indexes — for Postgres or MySQL.
- SQL to DBML Converter Convert SQL CREATE TABLE statements into DBML for dbdiagram.io — tables, columns and inferred references — to document an existing database.
- SQL to Mermaid ER Diagram Convert SQL CREATE TABLE statements into a Mermaid erDiagram — entities, attributes and relationships from the foreign keys — to drop into Markdown docs.
- SQL to JSON Schema Convert SQL CREATE TABLE statements into a JSON Schema — column types mapped, NOT NULL into required — to validate rows or generate API contracts.
- MySQL EXPLAIN Visualizer Paste MySQL EXPLAIN output (tabular or JSON) and get a readable plan — join order, access type, key used and rows examined — with the full-scan warnings highlighted.
- cURL to Go Converter Convert a cURL command into idiomatic Go using net/http — method, headers, body and query handled, with a ready-to-run http.NewRequest snippet.
- cURL to PHP Converter Turn a cURL command into PHP — native curl_* calls with options for headers, POST body, method and auth, ready to paste into any PHP project.
- cURL to Rust Converter Convert a cURL command into Rust using the reqwest crate — async client builder with headers, body and method mapped to a compilable example.
- cURL to Java Converter Convert a cURL command into Java using the java.net.http HttpClient — builder with headers, method and body, no external HTTP library required.
- cURL to C# Converter Convert a cURL command into C# using HttpClient — request message with headers, method and content body, ready for .NET projects.
- HAR to cURL Converter Paste a HAR file exported from browser DevTools and get a cURL command for every request — method, headers, cookies and post data reconstructed.
- YAML Viewer View YAML as a collapsible tree or convert it to JSON — validates syntax and handles anchors, multi-line strings and nested maps. Runs in your browser.
- TOML Viewer Read a TOML config as a collapsible tree or JSON — tables, arrays of tables, inline tables, dates and typed values, all parsed in your browser.
- XML Viewer View XML as a collapsible, highlighted tree or pretty-print the source — namespaces, attributes, CDATA and comments. Checks well-formedness in your browser.
- TSV Viewer View tab-separated data as a sortable, filterable table — optional header row, numeric-aware sorting and column counts. Runs in your browser.
- INI Viewer Read an INI, .conf or .cfg file as clean per-section key/value tables or nested JSON — handles sections, ; and # comments and quoted values. In your browser.
- Java Properties Viewer View a Java .properties file as a clean key/value table or JSON — comments, line continuations, Unicode escapes and = or : separators. In your browser.
- Plist Viewer Read an Apple XML property list as a typed, collapsible tree — dicts, arrays, dates, data and every plist type. Parsed entirely in your browser.
- GeoJSON Viewer Paste GeoJSON and see its points, lines and polygons drawn on a tile-free map, plus a feature and property breakdown. Validated in your browser.
- GPX Viewer Open a GPX file and see the track drawn with distance, elevation gain, point count and duration. Tracks, routes and waypoints, parsed in your browser.
- KML Viewer Open a KML file and see its placemarks, paths and polygons drawn on a tile-free map, with names and descriptions. Parsed entirely in your browser.
- WKT Viewer Paste Well-Known Text geometry — POINT, LINESTRING, POLYGON, the MULTI variants or a GEOMETRYCOLLECTION — and see it drawn with a structure breakdown. In your browser.
- Jupyter Notebook (.ipynb) Viewer Open a Jupyter .ipynb file and read it as a rendered notebook — Markdown, code and outputs including images and tracebacks. Parsed in your browser.
- ZIP Viewer Open a .zip archive and list every file and folder with size, compression method and date — and preview text files in place. No extraction, nothing uploaded.
- XLSX Viewer (Open Excel Files) Open an .xlsx or .xls spreadsheet and read every sheet as a clean table with formatted cells and sheet tabs. No Excel needed; nothing uploaded.
- DOCX Viewer (Open Word Files) Open a Word .docx and read it as a clean formatted page — headings, lists, tables, images and links. No Word needed; converted in your browser.
- EXIF Viewer (Photo Metadata) Open a JPEG or TIFF and read its EXIF — camera, exposure, ISO, lens, timestamps and GPS location. Check what a photo reveals before sharing. Nothing uploaded.
- Graphviz DOT Viewer Paste Graphviz DOT and see the diagram render live as SVG — the real engine via WebAssembly. Nodes, edges, clusters and styling. Nothing uploaded.
- LaTeX Math Viewer Paste LaTeX math and see it render live as typeset equations — fractions, integrals, matrices and aligned environments via KaTeX. Nothing uploaded.
Markdown
36 tools →- Markdown Previewer Live preview Markdown with GitHub-flavored syntax, tables, and code highlighting.
- HTML to Markdown Convert HTML to clean Markdown. Preserves links, lists, tables, and code blocks.
- Markdown Table Generator Build Markdown tables visually. Paste TSV/CSV, get a Markdown table.
- Markdown TOC Generator Generate a table of contents from Markdown headings. GitHub-compatible anchors.
- Markdown to HTML Converter Convert Markdown to clean semantic HTML. GFM tables, code, task lists.
- README Badge Builder Build shields.io badges for npm, GitHub stars, build status, license, etc.
- Markdown Table to CSV Convert Markdown tables back to CSV. Handles multi-line cells and alignment markers.
- CSV to Markdown Table Convert CSV (or TSV) to a clean Markdown / GFM table. Picks delimiter, aligns columns.
- Markdown to PDF Converter (Browser Print) Render Markdown to a styled HTML preview, then print to PDF via the browser. No upload.
- Markdown Table to HTML Converter Convert a GitHub-flavored Markdown table to HTML <table> markup. Handles alignment, escaping, multi-line cells.
- Markdown to Jira (Wiki Markup) Converter Convert Markdown to Atlassian Wiki Markup (Jira / Confluence syntax). Headers, lists, code blocks, links.
- Markdown Cleaner / Normalizer Normalize Markdown: consistent heading style, list markers, code fences, trailing whitespace, redundant blank lines.
- Markdown Frontmatter Editor (YAML / TOML / JSON) Edit Jekyll / Hugo / Astro Markdown frontmatter visually. Add / remove / rename fields, switch between YAML / TOML / JSON.
- Mermaid in Markdown Preview Preview Markdown with embedded Mermaid diagrams (flowcharts, sequence, gantt). Live render in browser.
- Markdown Checklist Generator (Task Lists) Build GitHub-style Markdown task lists with nesting and progress tracking. Copy as MD or render as HTML.
- Markdown Link Extractor (All Links, Images, References) Extract every link from a Markdown document. Inline, reference-style, autolinks, images. Output as list / JSON.
- Markdown Image Extractor (URLs, Alt Text, Sizes) Extract every image reference from a Markdown document. Get URL, alt text, optional dimensions.
- Markdown HTML Escape (Strip / Escape Inline HTML) Escape or strip inline HTML in Markdown. Useful for accepting user-supplied markdown without XSS risk.
- Markdown Callout / Admonition Builder (GitHub, Obsidian) Build GitHub > [!NOTE] or Obsidian > [!info] callouts visually. Live preview.
- Markdown Heading Anchor Generator (GFM slug) Generate GitHub-style anchor IDs for Markdown headings. Slugify with GFM rules.
- Markdown to Slack mrkdwn Converter Convert standard Markdown into Slack mrkdwn — bold, italics, links, lists, and inline code.
- Markdown to Plain Text Strip all Markdown syntax to clean plain text — removes headings, emphasis, links, code fences, and lists.
- Markdown Reference Link Converter Convert inline Markdown links to reference-style links (and back) to keep long documents readable.
- Markdown to BBCode Converter Convert Markdown into BBCode for forums — bold, italics, links, images, lists, quotes, and code blocks.
- Markdown Escape Tool Escape special Markdown characters so text renders literally — no accidental bold, headings, or links.
- Markdown List Converter Turn plain lines into a Markdown list and convert between bullet, numbered, and task-list styles.
- Markdown to AsciiDoc Converter Convert Markdown to AsciiDoc — headings, formatting, code blocks, links, images, lists, and quotes.
- Table to Markdown Converter Convert CSV, TSV, or pasted Excel cells into a clean Markdown table with alignment and padding.
- Markdown to reStructuredText Converter Convert Markdown to reStructuredText for Sphinx — headings, code-blocks, links, images, lists, quotes.
- Markdown Table of Contents Generator Generate a clickable TOC from Markdown headings with GitHub anchor links, adjustable depth, and styles.
- Markdown Table Formatter Align and prettify a Markdown pipe table, padding cells and normalizing the separator row, or compact it.
- Markdown to Confluence Converter Convert Markdown into Atlassian Confluence wiki markup — headings, formatting, links, code, and tables.
- Markdown to Textile Converter Convert Markdown into Textile markup — headings, bold and italic, links, images, lists, code, and tables.
- Markdown Reading Time Calculator Estimate reading time and count words and characters of a Markdown article, ignoring syntax, at an adjustable wpm.
- Markdown Heading Numberer Add hierarchical section numbers (1, 1.1, 1.2) to Markdown headings, with a chosen top level and separator.
- Textile Viewer Paste Textile markup and see the formatted HTML render live side by side — headings, lists, links, tables and code. Converted entirely in your browser.
Color & Design
62 tools →- Color Converter Convert between HEX, RGB, HSL, HSV, OKLCH, and named CSS colors.
- Color Palette from Image Extract a 6-color palette from any image. k-means clustering in the browser.
- CSS Gradient Generator Build linear, radial, conic CSS gradients visually. Copy as CSS.
- CSS Box Shadow Generator Build CSS box-shadow visually. Multiple layers, inset, spread, blur.
- CSS clamp() Generator Generate fluid CSS clamp(min, preferred, max) for typography and spacing.
- Glassmorphism CSS Generator Frosted-glass CSS with backdrop-filter, border, shadow.
- CSS Easing Function Picker Pick a cubic-bezier easing curve visually. Includes common presets.
- CSS Button Generator Build CSS buttons visually: padding, radius, color, shadow, hover. Copy CSS.
- CSS Border Radius Generator Build any border-radius shape — equal corners, per-corner, elliptical.
- CSS Triangle Generator Generate pure-CSS triangles (tooltip arrows, dropdown indicators) with the border trick.
- CSS Animation Generator Build CSS @keyframes animations visually. Fade, slide, bounce, pulse, spin.
- CSS Flexbox Playground Live flexbox playground. justify-content, align-items, gap, wrap — see results instantly.
- CSS Grid Generator Build a CSS grid layout visually. Tracks, gaps, named areas.
- WCAG Color Contrast Checker Check WCAG AA/AAA contrast between any two colors. Suggestions to pass.
- CSS Aspect Ratio Calculator Compute aspect-ratio CSS for any dimensions. 16:9, 4:3, golden ratio presets.
- CSS Scrollbar Designer Style scrollbars cross-browser. Webkit + Firefox + standard. Live preview.
- CSS Variable Extractor Extract all CSS custom properties (variables) from any stylesheet.
- Tailwind Color Picker Browse the Tailwind CSS color palette. Click any shade to copy HEX or class name.
- CSS Text Shadow Generator Visually build CSS text-shadow declarations. Multi-shadow stack, presets, copy-to-clipboard.
- SVG Blob Generator Generate organic SVG blob shapes for hero backgrounds. Adjustable complexity + randomness seed.
- CSS Spinner / Loader Generator Generate pure-CSS loading spinners (ring, dots, bars). Copy-paste HTML + CSS.
- CSS Filter Playground (Blur, Brightness, Hue) Live visual playground for the CSS filter property. Stack effects, copy declaration.
- CSS Skeleton Loader Generator Generate animated skeleton placeholder loaders (cards, lines, avatars). Pure CSS.
- CSS Color Name Finder (Nearest Named Color) Enter any hex / RGB / HSL color; get the nearest CSS named color. 147 named colors + most popular Crayola / Pantone names.
- HSL ↔ RGB ↔ HEX ↔ OKLCH Color Converter Convert between HSL, RGB, HEX, OKLCH, OKLAB, HWB color formats. Live preview, copy-to-clipboard.
- CSS Scrollbar Styler (Webkit + Firefox) Visually design a custom CSS scrollbar. Generates ::-webkit-scrollbar rules + scrollbar-color (Firefox) declarations.
- CSS Gradient Generator (Linear, Radial, Conic) Visual CSS gradient builder. Linear, radial, conic. Multiple stops, copy CSS, save presets.
- CSS clip-path Generator (Polygon, Circle, Inset) Visually build a CSS clip-path value. Polygon (drag vertices), circle, ellipse, inset. Live preview.
- Color Blender (Mix Two Colors) Blend two colors at any ratio. Linear RGB and perceptually-uniform OKLCH interpolation modes.
- Extract Color Palette from Image Drop an image; extract its dominant N colors via k-means clustering. Get hex / RGB values to use in CSS.
- CSS Conic Gradient Generator (Pie Charts, Color Wheels) Build CSS conic-gradient values visually. Multiple stops, custom start angle. Perfect for pie charts and color wheels.
- Color Shades Generator (Darker Variations) Generate 10 shades darker than a base color. Useful for hover states, dark mode variants.
- Color Tints Generator (Lighter Variations) Generate 10 lighter tints of a base color. Useful for backgrounds, disabled states.
- Monochromatic Color Palette Generator Generate a monochromatic palette (shades + tints of one hue). 9-step Tailwind-style scale.
- Triadic / Complementary / Analogous Palette Generate triadic, complementary, split-complementary, analogous, tetradic palettes from any base color.
- Color Contrast Grid (All Pairs vs WCAG) Test contrast ratios between every pair of colors in your palette. WCAG AA / AAA flags.
- Hex to RGBA Converter (With Alpha) Convert hex color (with or without alpha) to rgba() with adjustable transparency.
- CSS text-decoration Generator (Underline, Wavy) Build text-decoration values visually: line, style (solid, wavy, dotted), color, thickness, underline-offset.
- CSS overflow Behavior Tester Visualize CSS overflow: visible / hidden / scroll / auto / clip. With and without overflow-x / overflow-y.
- CSS Grid to Flexbox Converter (Common Layouts) Convert common CSS grid layouts (3-column, holy grail) to flexbox equivalents. Side-by-side comparison.
- CSS Modular Typography Scale Generator Generate a modular type scale (1.125, 1.25, 1.333, etc.) for h1-h6. Output as CSS custom properties.
- Complementary Color Palette Generator Find the complementary color for any hex and build a balanced palette around the opposite hue.
- CMYK to RGB Converter Convert colors between CMYK and RGB/hex. See print-style CMYK percentages alongside screen RGB values.
- HSV / HSB to RGB Converter Convert between HSV (HSB) and RGB/hex. The hue-saturation-value model used by most color pickers.
- CSS Specificity Calculator Calculate the specificity of any CSS selector as an (a,b,c) triple, compare selectors to see which wins, and understand :is(), :not(), :where() and pseudo-elements.
- CSS Media Query Generator Build CSS @media queries visually — min/max width with Tailwind and Bootstrap presets, orientation, prefers-color-scheme, reduced-motion, hover and pointer.
- OKLCH Color Picker Pick colors in OKLCH with lightness, chroma and hue sliders and get oklch(), hex, rgb and hsl instantly, with an sRGB gamut warning. Runs in your browser.
- CSS Unit Converter Convert between px, rem, em, %, pt, vw, vh and more — set root and parent font size and viewport, and copy any value. Runs in your browser.
- APCA Contrast Checker Check text contrast with APCA — the algorithm behind WCAG 3 — which models real readability better than the old 4.5:1 ratio. Get the Lc value and the minimum font size it allows.
- CSS color-mix() Generator Build a CSS color-mix() function visually — pick two colors, a color space (srgb, oklch, hsl) and the percentage — with a live swatch and copy-ready output.
- CSS @property Generator Generate an @property at-rule to register a typed custom property — syntax, inherits and initial-value — so a CSS variable can animate and stay valid.
- CSS Cascade Layers Visualizer Lay out @layer order and see which rule wins — cascade layers change specificity resolution, and this shows the winning declaration across layers.
- CSS Nesting ↔ Flat Converter Convert between nested CSS (the native & syntax) and flat, expanded rules — both directions — to adopt or unwind CSS nesting.
- CSS View Transitions Generator Generate the CSS for the View Transitions API — view-transition-name and the ::view-transition pseudo-element animations — for smooth page and state transitions.
- CSS Scroll Snap Generator Build a CSS scroll-snap container visually — snap type, alignment and padding — for carousels and full-page sections, with a live demo and copy-ready CSS.
- CSS Scroll-Driven Animation Generator Generate scroll-driven animations with scroll-timeline / view-timeline and animation-timeline — reveal-on-scroll and progress effects in pure CSS, no JS.
- CSS Anchor Positioning Playground Experiment with CSS anchor positioning — anchor() and position-area — to tether tooltips and popovers to an element without JavaScript, and copy the CSS.
- styled-components / Emotion to CSS Convert styled-components and Emotion template literals into plain CSS — extract the rules, resolve simple interpolations into custom properties — to migrate off CSS-in-JS.
- Line-Height Calculator Find the right line-height for a font size and measure — unitless ratio and the resulting pixel leading — for comfortable, readable body text.
- CSS to Tailwind Converter Map plain CSS declarations to the nearest Tailwind utility classes — colors, spacing, typography and layout matched against the default theme scale.
- SCSS to CSS Converter Compile SCSS to plain CSS in the browser — variables, nesting, & parent selectors and simple mixins expanded into standards CSS you can ship.
- Less to CSS Converter Convert Less to plain CSS — @variables, nesting and parent selectors resolved into standard CSS rules, all processed locally in your browser.
Date & Time
33 tools →- Unix Timestamp Converter Convert between Unix timestamps, ISO 8601, and human-readable dates.
- Cron Expression Parser Parse cron expressions, see next 10 fire times, and get plain-English descriptions.
- Cron to Plain English Translate cron expressions to natural-language descriptions.
- Time Difference Calculator Compute the difference between two timestamps. Days/hours/minutes/seconds.
- Cron Expression Builder Build cron expressions visually: pick minute/hour/day/month/weekday. See description.
- Cron Expression Decoder Decode any cron expression to plain English. See next 10 fires in your timezone.
- Timezone Converter Convert any time between timezones. Side-by-side comparison for distributed teams.
- Age Calculator (Years, Months, Days) Calculate exact age from a birthdate. Years, months, days, hours, total days lived.
- Duration Formatter (ISO 8601, Humanize) Convert between seconds, ISO 8601 duration, and human-friendly "2h 15m" strings.
- ISO 8601 Datetime Builder + Parser Construct or parse ISO 8601 datetimes. UTC, offsets, fractional seconds, durations, intervals.
- Relative Time Formatter ("2 hours ago") Format any timestamp as a relative phrase: "5 minutes ago", "in 2 weeks". 60+ locales via Intl.RelativeTimeFormat.
- Business Days Calculator (Skip Weekends + Holidays) Count business days between two dates, or add N business days to a date. Skips weekends and configurable holidays (US, UK, EU presets).
- Countdown Timer Generator (Embeddable HTML) Build a live countdown to any future date. Outputs self-contained embeddable HTML / CSS / JS snippet.
- Duration Between Two Dates (Years / Months / Days / Hours) Calculate exact duration between two timestamps. Years, months, weeks, days, hours, minutes, seconds.
- Time Since Event Counter (Live) How long has it been since X? Live count of years / days / hours / minutes elapsed since any past date.
- Day of Week from Date (Past, Present, Future) What day of the week was / will it be? Enter any date 1900-2100 and get the weekday. Plus ISO week number.
- Date to Roman Numerals (Copyright Notation) Convert a date to Roman numerals — common in copyright notices (MMXXVI). Year, month, day formats.
- IANA Timezone List (Searchable, 400+ Zones) Complete IANA timezone database. Search by city, country, offset. Current local time in each.
- Current Unix Timestamp (Live) Live Unix timestamp in seconds, milliseconds, and ISO 8601. Auto-updates every second; one-click copy.
- ISO Week Number Calculator Find the ISO 8601 week number for any date, plus the current week, with week start and end dates.
- Date Add / Subtract Calculator Add or subtract days, weeks, months, and years from any date and get the resulting date instantly.
- Unix Timestamp Converter Convert a Unix epoch timestamp to a human date and back. Seconds or milliseconds, UTC and local time.
- Date Format Converter Reformat a date from one pattern to another — ISO, US, European, custom tokens. Parse and re-emit any layout.
- Leap Year Checker Check whether any year is a leap year and list leap years in a range. Explains the divisible-by-4/100/400 rule.
- Weekday Finder — What Day of the Week Find the day of the week for any date, plus ISO weekday, day of year, ISO week, and days from today.
- Seconds to HH:MM:SS Converter Convert seconds to HH:MM:SS and back, with days, a human breakdown, and the ISO 8601 duration.
- Time Duration Calculator Calculate the duration between two date-times in years, months, days and total hours, minutes, seconds.
- Quarter of the Year Finder Find which quarter a date is in for both the calendar year and a custom fiscal year, with start and end dates.
- Decimal Time Converter Convert between HH:MM:SS and decimal hours for payroll and timesheets, plus decimal minutes and seconds.
- Nth Weekday of the Month Find the date of the first, second, third, fourth, fifth, or last given weekday in any month.
- ISO Week Date Converter Convert between a calendar date and the ISO-8601 week date (YYYY-Www-D) in both directions, with week numbers.
- Julian Day Converter (JD, MJD, JDN) Convert between a UTC date-time and the astronomical Julian Date, Modified Julian Date, and Julian Day Number.
- Day of the Year Converter (Ordinal Date) Convert a date to its day-of-year ordinal (1-366) and back, with days remaining and percent of the year elapsed.
DevOps
100 tools →- YAML Validator Validate and lint YAML against the spec. Catches duplicate keys and tab errors.
- CIDR / Subnet Calculator Parse CIDR notation, show network/broadcast/host range, subnet mask, IP count.
- HTTP Status Code Lookup Look up any HTTP status code with full meaning, category, and when to use it.
- Dockerfile Linter Lint a Dockerfile for common mistakes: missing version pins, root user, cache busters.
- .env Validator & Diff Validate .env files. Diff two .envs to spot drift between environments.
- Kubernetes Manifest Validator Validate K8s YAML manifests against the schema. Catches typos and missing fields.
- .editorconfig Generator Pick conventions and download a ready-to-commit .editorconfig file.
- .gitignore Generator Generate .gitignore from language/framework/editor templates. Combine multiple.
- .htaccess Generator Build .htaccess with redirects, HTTPS forcing, security headers, caching, gzip.
- nginx Config Generator Build common nginx blocks: SSL, reverse proxy, static site, security headers.
- .prettierrc Generator Build a .prettierrc with print width, tab width, semis, quotes, trailing commas.
- tsconfig.json Generator Build a strict, modern tsconfig.json for Node, bundlers, libraries, or Next.js.
- Webhook Request Builder Build a curl/fetch/Python webhook test request. Sign with HMAC-SHA256.
- HTTP Headers Explainer Paste a response header set; get explanation of each header and its security implications.
- HCL to JSON Converter Convert Terraform HCL2 to JSON for tooling or back-conversion. Browser-only.
- YAML Anchor / Alias Resolver Expand all YAML &anchors and *aliases to produce a fully de-aliased document.
- HTTP Cache-Control Decoder Decode and explain Cache-Control, Expires, ETag, and other HTTP cache headers.
- MAC Address Tools (Format, Vendor Lookup) Format / validate / normalise MAC addresses. Detect multicast, locally-administered. OUI vendor lookup.
- IP Address Tools (IPv4 / IPv6 Inspector) Parse, validate, expand, classify IPv4 and IPv6 addresses. Private / public / reserved detection.
- HTTP Request Builder (cURL, fetch, Python) Visually construct an HTTP request. Outputs cURL, fetch (JS), requests (Python), httpie commands.
- .env File Validator (Strict) Validate a .env file for syntax errors, duplicate keys, unsafe characters, missing quotes around special values.
- Lighthouse Score Interpreter Paste a Lighthouse JSON report. Get plain-English explanations of each metric and how to improve scores.
- Core Web Vitals Explainer (LCP, INP, CLS) Visual reference for Core Web Vitals thresholds. LCP, INP, CLS, FCP, TTFB explained with good / needs improvement / poor cutoffs.
- OAuth 2.0 Flow Visualizer (Auth Code + PKCE) Step-by-step OAuth 2.0 Authorization Code + PKCE flow visualizer. Build authorization URLs, parse callback redirects.
- Cron Next Runs (Show Next N Executions) Given a cron expression, list the next N runs in your timezone. Validates 5- and 6-field cron, including @daily / @hourly.
- GraphQL Introspection Viewer Paste a GraphQL introspection JSON response. Render the full schema as a navigable tree with type / field / argument details.
- chmod Calculator (Linux File Permissions) Visual chmod calculator. Click owner/group/other × read/write/execute checkboxes; get octal (755) and symbolic (rwxr-xr-x) representations.
- CORS Header Tester (Preflight Simulator) Test CORS configuration. Simulates browser preflight request; flags missing Access-Control-Allow-Origin / Methods / Headers.
- DNS Record Types Explained (A, AAAA, CNAME, MX, TXT, SPF) Searchable reference for every DNS record type. A, AAAA, CNAME, MX, TXT, SPF, DKIM, DMARC, CAA, SRV, NS, SOA, PTR with use cases.
- Kubernetes Manifest Validator (YAML) Validate Kubernetes YAML manifests for syntax + required fields. Checks Deployment, Service, ConfigMap, Secret, Ingress, Pod, more.
- docker-compose.yml Validator Validate docker-compose.yml structure + service definitions. Common pitfalls: depends_on without condition, version drift, network typos.
- OpenAPI 3 Spec Validator (Swagger) Validate an OpenAPI 3.0 / 3.1 spec (YAML or JSON). Checks structure, required fields, common pitfalls.
- Log Format Parser (Apache, Nginx, JSON, syslog) Parse common log formats into structured rows. Apache Common / Combined, Nginx default, JSON lines, RFC 5424 syslog.
- SSH ~/.ssh/config Generator (Visual) Visually build an ~/.ssh/config file. Host aliases, jump hosts (ProxyJump), key auth, ports.
- systemd Unit File Builder (.service) Visually build a systemd .service unit file. Type, ExecStart, restart policy, environment, security hardening.
- crontab Expression Helper (Build Visually) Visually build a crontab schedule. Pick minute / hour / day / month / weekday from dropdowns; preview next runs.
- Glob Pattern Tester (* ** ? [...]) Test glob patterns against filenames. Bash / git / .gitignore style. * matches anything, ** matches across slashes, [abc] character class.
- nginx Rewrite Rule Tester Test nginx rewrite / location / try_files rules against a request URL. Visual flag explanation.
- Webhook Payload Generator (Stripe, GitHub, Slack) Generate realistic test payloads for Stripe / GitHub / Slack / Discord webhooks. With matching signature.
- HTTP Status Code Cheat Sheet (1xx-5xx) Quick reference for every HTTP status code. When to use each, common mistakes, IANA category.
- Dockerfile ARG ↔ ENV Converter Convert between Dockerfile ARG (build-time) and ENV (runtime) directives. Helper for moving variables between scopes.
- Content Security Policy (CSP) Builder Visually build a Content-Security-Policy header. Per-directive controls, common preset templates.
- nginx Server Block Builder Generate an nginx server { } block from form inputs. Reverse proxy, static site, TLS termination presets.
- IPv4 Subnet Calculator (CIDR, Mask, Range) Calculate network, broadcast, hosts, mask from an IPv4 + CIDR. Inverse: get CIDR from mask.
- Browserslist Query Checker (caniuse / Autoprefixer) Test a Browserslist query ('> 1%, last 2 versions'). See which browsers match and global usage %.
- Chrome Extension Manifest V3 Builder Visually build a manifest.json for a Chrome / Edge / Firefox extension. MV3 schema, permissions, service worker, action.
- Natural Language to Cron Expression Convert phrases like "every Monday at 9am" to a valid cron expression. Handles minute / hour / day / weekday / month patterns.
- CIDR to IP Range (and Back) Convert CIDR notation (10.0.0.0/8) to first / last IPs. Reverse: convert IP range to minimum CIDR set.
- GitHub Pages 301 Redirect HTML Builder Generate the meta-refresh + JS HTML snippet for a GitHub Pages redirect. Multiple paths supported.
- Terraform tfvars to JSON Converter Convert a Terraform .tfvars (HCL) variable file to .tfvars.json and back — strings, numbers, bools, lists, and maps.
- GitHub Actions Workflow Validator Validate a GitHub Actions workflow YAML — triggers, jobs, steps, runs-on, and common mistakes — in your browser.
- .dockerignore Generator Generate a .dockerignore from language and framework presets to shrink the build context and speed up docker build.
- CODEOWNERS File Generator Build a GitHub or GitLab CODEOWNERS file from path patterns and owners, with validation and correct ordering.
- Renovate Config Generator Generate a renovate.json for Renovate Bot — schedule, automerge, grouping, labels, and package rules.
- AWS Cron Expression Generator Build and explain AWS EventBridge and CloudWatch cron() and rate() schedule expressions, including ?, L, W, and #.
- Ansible Playbook Generator Scaffold an Ansible playbook YAML from hosts, become, variables, and common task modules — copy and run.
- Dockerfile Generator Generate a production-ready Dockerfile for Node, Python, Go, Rust, Java, PHP, or static sites — multi-stage, non-root, with a healthcheck.
- Docker Compose Generator Build a docker-compose.yml with your app plus Postgres, MySQL, Redis, Mongo, or Nginx — ports, volumes, env, and healthchecks.
- Helm Chart Generator Scaffold a Helm chart — Chart.yaml, values.yaml, deployment, service, and optional ingress — from a few fields.
- Kubernetes Manifest Generator Generate a Kubernetes Deployment, Service, and optional Ingress and ConfigMap YAML with resource limits and probes.
- Kubernetes Resource Calculator Size Kubernetes CPU and memory requests and limits across replicas and work out how many nodes a workload needs.
- AWS IAM Policy Generator Build an AWS IAM policy JSON from services, actions, resource ARNs, and conditions — least-privilege, ready to paste.
- S3 Bucket Policy Generator Generate an S3 bucket policy for common cases — public read, CloudFront OAC, SSL-only, IP allow-list, and cross-account.
- CloudFormation Template Generator Scaffold an AWS CloudFormation template in YAML or JSON with S3, DynamoDB, Lambda, SQS, and SNS resources and parameters.
- GitLab CI Generator Generate a .gitlab-ci.yml with build, test, lint, and deploy stages for Node, Python, Go, and more — cache and artifacts included.
- GitHub Actions Workflow Generator Generate a GitHub Actions CI workflow YAML — triggers, a version matrix, and install, lint, test, and build steps.
- Terraform Graph Visualizer Paste Terraform HCL and see the resource dependency graph — resources, references, and edges rendered as a diagram, in your browser.
- Dependabot Config Generator Generate a .github/dependabot.yml for npm, pip, Docker, Actions, Go, Maven, Composer, and more — schedule, limits, and reviewers.
- Prometheus Alert Rule Generator Build Prometheus alerting rules YAML from presets — high CPU, memory, disk, latency, error rate, and instance-down — with editable thresholds.
- Logrotate Config Generator Generate a logrotate configuration block — rotation frequency, retention count, compression, size triggers, create vs copytruncate and pre/post-rotate scripts — ready for /etc/logrotate.d/.
- Supervisor (supervisord) Config Generator Generate a Supervisor program section — command, working directory, user, numprocs, autostart and autorestart, environment, stop signal and logging — for /etc/supervisor/conf.d/.
- PM2 Ecosystem Config Generator Generate a PM2 ecosystem.config.js — app name, script, fork vs cluster mode, instances, watch, max_memory_restart, environment variables and cron restart.
- .gitattributes Generator Generate a .gitattributes file — line-ending normalization, forced LF or CRLF, binary markers, Git LFS tracking, GitHub Linguist overrides, diff drivers and export-ignore.
- Nginx Rate Limit Config Generator Generate nginx rate-limiting config — limit_req_zone and limit_req with burst and nodelay, optional connection limiting, custom key, memory zone size and status code.
- Quartz Cron Expression Validator Validate and explain a Quartz cron expression — 6 or 7 fields from seconds to year, the ? L W and # special characters, named months and weekdays, and a plain-English breakdown of every field.
- Cron Dialect Converter Convert a cron expression between Unix crontab, Quartz, Spring and AWS EventBridge — remapping day-of-week numbering, adding or dropping the seconds and year fields, and applying the ? rule.
- Terraform State (tfstate) Viewer Inspect a Terraform state file — summary metrics, resource addresses grouped by module, notable attributes per resource, provider list and outputs, with sensitive outputs hidden.
- Kustomize Build Preview Preview common Kustomize transformers — namePrefix and nameSuffix, namespace, commonLabels and annotations, image name/tag/digest overrides and replica counts — applied to your base manifests.
- CAA Record Generator Generate CAA DNS records that pin which certificate authorities may issue for your domain — issue, issuewild and iodef — to block mis-issuance.
- DNS TTL Calculator Translate DNS TTL seconds into plain durations, and plan a migration: how long before a record change fully propagates and when to lower TTL ahead of a cutover.
- AWS ARN Parser & Builder Parse an AWS ARN into partition, service, region, account and resource — and build one from the parts — so you stop hand-editing IAM and resource ARNs.
- Git Branch Name Generator Generate a clean, conventional Git branch name from a ticket and description — type/scope, kebab-case, length-capped — matching feature/ and fix/ conventions.
- Bash getopts Generator Generate a Bash getopts argument-parsing block from the flags you define — short options, required arguments and a usage() — ready to paste into a script.
- kubectl Command Builder Build a kubectl command from a form — verb, resource, namespace, selector and output — for the get / describe / logs / scale calls you can never quite remember.
- S3 URI / URL / ARN Converter Convert between the three ways to point at an S3 object — s3:// URI, https:// URL and ARN — and pull out bucket, key and region.
- Linux Signal Reference Look up Linux signals — SIGTERM, SIGKILL, SIGHUP, SIGINT and the rest — with the number, default action and when to send each. Searchable.
- Unix Exit Code Reference Look up Unix and Linux exit codes — what 1, 2, 126, 127, 128+n and 130 mean, and how a signal maps to 128+signal — to decode a failing command or CI step.
- Makefile Generator Generate a Makefile from the tasks you list — .PHONY targets, variables and a help target — so a project gets make build / test / run without the tab-vs-space pain.
- find Command Builder Build a find command from a form — name pattern, type, size, mtime and -exec — and get the exact syntax instead of guessing the predicates.
- grep / ripgrep Command Builder Build a grep or ripgrep command from a form — pattern, recursion, ignore-case, context lines and file globs — with the right flags for each tool.
- .gitconfig Generator Generate a ~/.gitconfig — user identity, sensible defaults, aliases, pull and rebase and line-ending settings — to drop onto a fresh machine.
- rsync Command Builder Build an rsync command from a form — archive, delete, exclude, compression, dry-run and SSH — and understand exactly what the flags will do before it runs.
- dig Command Builder Build a dig command — record type, @resolver, +short or +trace and reverse lookup — for the DNS query you need without memorizing the options.
- Justfile / Taskfile Generator Generate a justfile or Taskfile from your tasks — recipes, variables and dependencies — a friendlier task runner than Make.
- AWS IAM Policy Explainer Paste an AWS IAM policy JSON and get a plain-English explanation — who can do what to which resources, and which statements are dangerously broad (Action: *, Resource: *).
- ANSI Color Code Generator Build ANSI escape codes for colored terminal output — foreground, background, bold and underline — with a live preview and copy-ready sequences for bash, Python or Node.
- scp Command Builder Build an scp command from a form — local and remote paths, port, recursive and identity file — with the right ordering and quoting for the copy you want.
- TCP/UDP Port Number Reference Look up TCP and UDP port numbers — what runs on 22, 80, 443, 3306, 5432, 6379, 8080 — and search by port or by service. The well-known and common dev ports.
- Dotenv (.env) Viewer View a .env file as a clean key/value table — parses quotes, export prefixes and comments, and flags values that look like secrets. Parsed in your browser.
- JUnit XML Viewer Open a JUnit or xUnit XML test report and read it as a pass/fail tree with per-test timings and failure messages. Parsed entirely in your browser.
Web & SEO
126 tools →- QR Code Generator Generate QR codes for URLs, text, wifi, contact cards. Download as PNG or SVG.
- Meta Tag / OG Card Previewer See how your page looks when shared on Twitter, Facebook, LinkedIn, Slack.
- URL Slug Generator Convert any title into a clean URL slug. Handles unicode, custom separators.
- Sitemap.xml Validator Validate a sitemap.xml: schema, URL count, lastmod dates, priority ranges.
- SVG Optimizer / Minifier Strip metadata, simplify paths, minify SVG markup. Often 50-70% smaller.
- Favicon Generator Upload an image, get favicon.ico + every size for iOS, Android, browser tabs.
- RSS / Atom Feed Validator Validate RSS 2.0 and Atom feeds. Catches missing required fields.
- OpenAPI Spec Viewer Paste an OpenAPI/Swagger spec, get interactive docs without any setup.
- URL Parser & Builder Decompose a URL into protocol/host/path/query. Build URLs from parts.
- robots.txt Tester Test whether a URL is allowed for a given user agent against a robots.txt.
- Schema.org JSON-LD Generator Build Article, Product, FAQ, Breadcrumb, Organization JSON-LD blocks.
- Image Compressor — In-Browser Compress JPG / PNG / WebP entirely in browser. Quality slider, no upload.
- robots.txt Generator Build a robots.txt with allow/disallow rules per user agent. Sitemap declarations.
- Mermaid Live Preview Write Mermaid diagrams (flowcharts, sequence, ERD), see them rendered live.
- SVG Path Inspector Parse and visualize SVG <path> d attributes. See each command, point, control point.
- Lorem Picsum URL Builder Build placeholder image URLs. Dimensions, blur, grayscale, seed.
- UTM URL Builder Build UTM-tagged URLs for Google Analytics campaign tracking.
- Image Dimensions Reader Drop any image; see width, height, aspect ratio, file size, type. No upload.
- Image Metadata Stripper (EXIF) Remove EXIF, GPS, camera data from JPG/PNG. Browser-only — image never uploads.
- OpenGraph Image Builder Build 1200×630 share images in your browser. Background, title, subtitle, logo. Download PNG.
- Image Resizer (Browser-only) Resize JPG / PNG / WebP images in your browser. No uploads, full quality control.
- Image Format Converter (JPG ↔ PNG ↔ WebP ↔ AVIF) Convert images between JPG, PNG, WebP, AVIF in your browser. No upload, lossless option.
- Image Cropper (Canvas) Crop images in your browser with a draggable selection. Save to JPG / PNG / WebP.
- Image Placeholder Generator Generate placeholder images at any size with custom color and text overlay. Browser-only.
- User Agent Parser Parse a User-Agent string into browser, version, OS, device. Useful for log analysis.
- User Agent String Generator Generate User-Agent strings for browsers, mobile devices, and bots. For testing only.
- QR Code Reader (Upload or Camera) Read QR codes from an uploaded image or live camera. Browser-only — no upload to a server.
- SVG to PNG Converter (Custom Size) Convert SVG to PNG at any resolution. Preserves transparency. Browser-only, batch supported.
- PNG to ICO Favicon Converter Convert PNG images into multi-size .ico favicons. 16/32/48/64/128/256 in one file.
- WebP to PNG Converter Convert WebP images back to PNG. Preserves transparency. Browser-only.
- JPEG Quality Comparator (Side-by-Side) Compare a JPEG at multiple quality levels side-by-side. Find the sweet spot between size and visual quality.
- SVG Sprite / Icon Set Extractor Paste an SVG sprite or symbol set. Get a downloadable preview of every individual icon. Lucide, Heroicons, custom sprites.
- File Extension ↔ MIME Type Lookup Look up the MIME type for any file extension, or extensions for a MIME type. 1000+ entries indexed.
- Image Color Picker (Eyedropper Tool) Upload an image; click anywhere to pick the exact RGB / hex color of that pixel. Browser-only.
- SVG Cleaner (Strip Metadata + Comments) Strip editor metadata (Sketch / Figma / Illustrator), comments, and unused IDs from SVG. Smaller files, cleaner code.
- Browser Fingerprint Info (What Sites See) See what fingerprinting data your browser exposes: UA, screen, timezone, language, fonts, canvas hash, WebGL renderer.
- OpenGraph + Twitter Card Tester (Preview) Paste HTML or URL meta tags. Preview how the page renders on Facebook, Twitter, LinkedIn, iMessage.
- noindex / robots Meta Tag Tester Test a URL's robots meta tag, X-Robots-Tag header, and robots.txt rules. See if Google can index it.
- sitemap.xml Builder (From URL List) Paste a list of URLs; get a valid sitemap.xml with priorities, changefreq, lastmod.
- SEO Analyzer (On-Page Audit + Score) Enter a URL or paste HTML; get a 0-100 on-page SEO score across 40+ checks: meta, headings, links, images, schema, social. Deep-links to fix tools.
- URI Template Builder (RFC 6570) Build URLs from RFC 6570 URI templates. Variable expansion, query parameters, list / map formats.
- OpenSearch Description XML Builder Generate the opensearch.xml file to add your site as a browser search engine. Firefox / Chrome / Edge compatible.
- HAR Viewer Inspect a HAR file in your browser — request waterfall, status codes, sizes, timings, and totals. Filter by type or URL. Nothing uploaded.
- Postman to cURL Convert a Postman collection or request into runnable curl commands — methods, headers, query params, auth, and raw/form/urlencoded bodies.
- DNS Lookup Query A, AAAA, MX, TXT, NS, CNAME, SOA, CAA, and SRV records for any domain over DNS-over-HTTPS via Google or Cloudflare. Shows TTLs and status.
- Google SERP Preview Preview how your title and meta description appear in Google search, with live pixel-width measurement to catch truncation. Desktop and mobile layouts.
- Security Headers Analyzer Paste HTTP response headers for a graded security report — HSTS, CSP, X-Content-Type-Options, X-Frame-Options, Referrer-Policy and more, plus leak detection.
- SPF Record Generator Build a valid SPF (v=spf1) TXT record from the senders you allow — include:, ip4:, ip6:, mx, a — with the right ~all or -all policy and a check against the 10-lookup limit.
- SPF Record Parser & Explainer Parse an existing SPF record and explain every mechanism and qualifier in plain English, count DNS lookups, and flag the things that break SPF (too many lookups, +all).
- DMARC Record Generator Build a DMARC (_dmarc TXT) record — p=none/quarantine/reject, rua/ruf reporting, pct and alignment — with a sane rollout from monitor to enforce.
- DMARC Record Checker Parse and validate a DMARC record — policy, reporting addresses, alignment and percentage — and warn about the misconfigurations that quietly let spoofing through.
- DMARC Aggregate Report Reader Paste a DMARC aggregate (RUA) XML report and get a readable table — which sources passed SPF and DKIM, which failed, and how many messages each sent.
- BIMI Record Generator Generate a BIMI DNS record so your verified logo shows next to email in supporting clients — the SVG location and optional VMC certificate.
- MTA-STS Record & Policy Generator Generate both the MTA-STS DNS TXT record and the policy file that enforces TLS on inbound mail — testing or enforce mode, MX list and max_age.
- TLS-RPT Record Generator Generate a TLS-RPT (_smtp._tls TXT) record so you receive reports when inbound mail fails TLS — paste the reporting address, get the record.
- Email Header Analyzer Paste raw email headers and trace the delivery path — every Received hop with delays, plus the SPF, DKIM and DMARC authentication results. Runs locally.
- MX Record Lookup Look up a domain's MX records live and see every mail server with its priority, sorted, plus the primary — to confirm where email for the domain is delivered.
- NS Record Lookup Find the authoritative nameservers for any domain — query its NS records live and see exactly which DNS servers answer for it, with TTLs.
- TXT Record Lookup Look up all TXT records for a domain and see SPF, DKIM, DMARC, domain-verification and other entries, each detected and labelled, with TTLs.
- SOA Record Lookup Read a zone's SOA record — primary nameserver, hostmaster email, serial, and the refresh, retry, expire and minimum timers — decoded into plain values.
- CAA Record Checker Check which certificate authorities are allowed to issue TLS certificates for a domain — look up its CAA records and read the issue, issuewild and iodef tags.
- A Record Lookup Find the IPv4 address a domain points to — query its A records live, list every IP with TTLs, and detect a CNAME alias if there is one.
- CNAME Lookup Check the CNAME record for any hostname and see exactly what it aliases to, with the TTL — confirm whether a subdomain points at a CDN or SaaS host.
- Reverse DNS Lookup Find the hostname an IPv4 or IPv6 address maps back to — build the reverse pointer name and query its PTR record live. Accepts a hostname too.
- DKIM Record Checker Look up and validate a domain's DKIM public key by selector — key type, version and whether it is valid or revoked. Probes common selectors if you don't know yours.
- BIMI Record Checker Look up a domain's BIMI record, preview the brand logo SVG it points to, and see whether a VMC certificate is referenced — the quick BIMI rollout check.
- DNSSEC Checker Check whether a domain is signed and validating — read the AD flag from a validating resolver, the DS record at the registrar and the zone's DNSKEY.
- DNS Propagation Checker Check whether a DNS change has reached the major public resolvers — query Google, Cloudflare and Quad9 at once and see whether they agree yet.
- MTA-STS Checker Check a domain's MTA-STS setup live — the _mta-sts TXT record, the policy file and its mode — and cross-check it against the real MX hosts to catch an enforcing policy that misses a mail server.
- Subdomain Finder Discover a domain's subdomains passively from public Certificate Transparency logs (crt.sh) — a deduplicated, copyable list with wildcards flagged, no scanning of the target.
- Certificate Transparency Search Search public Certificate Transparency logs for every TLS certificate issued under a domain — issuing CAs, validity dates and recent certs from crt.sh — to audit issuance and catch mis-issuance.
- security.txt Generator Generate an RFC 9116 security.txt file for /.well-known/ — Contact, Encryption, Policy, Expires — so researchers know where to report a vulnerability.
- HSTS Header Generator Build a Strict-Transport-Security header — max-age, includeSubDomains and preload — and understand what you commit to before submitting to the preload list.
- Disposable Email Detector Check whether an email domain is a disposable or throwaway provider — paste one or a list and screen out temp-mail signups before they hit your database.
- RFC 5322 Email Validator Validate email addresses against RFC 5322 syntax — local part, quoted strings, domain and IP literals — beyond the naive regex, with a per-address reason for failures.
- Product Schema (JSON-LD) Generator Generate Product schema.org JSON-LD — name, image, brand, offers with price and availability, and aggregateRating — for rich product results in Google.
- LocalBusiness Schema Generator Generate LocalBusiness JSON-LD — address, geo, opening hours, phone and price range — so your business is eligible for local rich results.
- JobPosting Schema Generator Generate JobPosting JSON-LD — title, hiringOrganization, location, salary and dates — required to appear in Google Jobs.
- Event Schema Generator Generate Event JSON-LD — dates, location or virtual location, offers and performer — for event rich results and the knowledge panel.
- Article Schema Generator Generate Article, NewsArticle or BlogPosting JSON-LD — headline, author, publisher, dates and image — for article rich results in Search and Discover.
- Recipe Schema Generator Generate Recipe JSON-LD — ingredients, steps, times, nutrition and rating — for the recipe rich result with cook time and stars.
- VideoObject Schema Generator Generate VideoObject JSON-LD — name, thumbnail, upload date, duration and embed URL — so videos can show as a rich result with a thumbnail.
- BreadcrumbList Schema Generator Generate BreadcrumbList JSON-LD from your page path so Google shows a breadcrumb trail instead of a bare URL in the result.
- HowTo Schema Generator Generate HowTo JSON-LD — ordered steps with images, tools and total time — to mark up a tutorial for the step-by-step rich result.
- Course Schema Generator Generate Course JSON-LD — name, provider and offers — so an online course is eligible for the course rich result.
- Organization Schema Generator Generate Organization JSON-LD — name, logo, URL, contact points and sameAs social profiles — for the knowledge panel and brand entity.
- JSON-LD Validator & Linter Paste JSON-LD and validate it — JSON syntax, @context and @type, and the required fields for common schema.org types — before you ship it.
- Twitter / X Card & OG Generator Generate Twitter/X Card and Open Graph meta tags — summary or summary_large_image — with a live preview of how the link will unfurl.
- ads.txt Generator & Validator Build a valid ads.txt file line by line — domain, publisher ID, DIRECT/RESELLER and the certification authority ID — for AdSense and programmatic buyers.
- Tab Order Visualizer Paste HTML and see the keyboard tab order — the sequence focusable elements receive focus, with positive tabindex traps and skipped controls flagged.
- Image Alt Text Checker Check image alt text quality — paste HTML or a list — and catch empty, missing, filename-as-alt and redundant 'image of' alt, with a fix for each.
- ARIA Roles Reference & Validator Look up WAI-ARIA roles — required attributes, allowed children and the keyboard interaction each implies — and validate that a role is being used correctly. Searchable.
- srcset & sizes Generator Generate a responsive img srcset and sizes — width descriptors and breakpoints — plus the matching picture element with WebP/AVIF, so the browser loads the right image.
- Heading Structure (H1-H6) Checker Paste HTML and audit the heading outline — H1 to H6 — flagging multiple H1s, skipped levels and empty headings that hurt accessibility and SEO.
- Microdata to JSON-LD Converter Convert inline schema.org microdata (itemscope / itemprop) into clean JSON-LD — Google's preferred format — without re-authoring the markup.
- RSS and Atom Feed Viewer Paste RSS or Atom XML and read it as a clean list of articles — title, date, author and summary, with namespaces and CDATA handled. In your browser.
- ICS Calendar Viewer Open an .ics calendar file and read every event — summary, time, location, organizer and recurrence — as clean cards. Parsed in your browser.
- vCard (.vcf) Viewer Read a vCard .vcf contact file as clean cards — names, phones, emails, addresses and orgs across vCard 2.1, 3.0 and 4.0. Parsed in your browser.
- Cookie Viewer Paste a Set-Cookie header or document.cookie string and read each cookie — name, value and attributes like Secure, HttpOnly, SameSite and Expires. In your browser.
- Font Viewer Preview a TTF, OTF, WOFF or WOFF2 font in your browser — sample text at every size, a glyph grid and the embedded name and version metadata. Nothing uploaded.
- EML Email Viewer Open an .eml email file and read it cleanly — From, To, Subject, date, headers and the decoded text or HTML body, with attachments listed. In your browser.
- HTML Viewer Paste HTML and see it render live in a sandboxed preview as you type — format the markup, toggle scripts safely and open it in a new tab. In your browser.
- SVG Viewer Paste SVG markup or load a file to preview it safely as an image, read its size, viewBox and element count, and export a PNG at any scale. In your browser.
- SSL Checker Check any site's live SSL/TLS certificate — expiry, issuer, hostname match, full chain, SANs, key type and which TLS versions the server accepts. Instant, no signup.
- SSL Certificate Expiration Checker See exactly when a website's SSL certificate expires — days remaining, the precise expiry date, issue date and issuer, read live from the server. Catch outages before visitors do.
- TLS Version Checker Test which TLS versions a server supports — TLS 1.0, 1.1, 1.2 and 1.3 probed individually — plus the negotiated protocol. Find deprecated protocols to disable for security and PCI.
- SSL Certificate Chain Checker Inspect the live chain of trust a server sends — leaf, intermediate and root — and confirm it is complete and ordered. Catch the missing-intermediate bug that breaks mobile and APIs.
- SSL SAN Checker List every Subject Alternative Name on a live certificate — apex, www, subdomains and wildcards — and confirm a host is covered. Verify multi-domain and wildcard certificates.
- SSL Cipher Checker See the cipher a site negotiates live — cipher suite, strength in bits, key type and size, signature algorithm, forward secrecy and protocol support. Sanity-check modern crypto fast.
- WHOIS Lookup Look up any domain's live registration record — registrar, creation and expiry dates, name servers, status codes and the full raw WHOIS, read from the registry via WHOIS and RDAP.
- Domain Age Checker Check how old a domain is — the exact registry creation date and age in years and days, read live. Domain age is a real trust signal for fraud screening and SEO research.
- Domain Expiration Checker See exactly when a domain expires — the registry expiry date and days remaining, read live, so you can renew before the registration lapses and the site goes dark.
- RDAP Lookup Query a domain via RDAP, the structured JSON replacement for WHOIS — registrar, dates, status and name servers, plus the full raw RDAP response. Reliable, machine-readable data.
- Domain Registrar Lookup Find which registrar a domain is registered with — registrar name, IANA ID, WHOIS server, transfer-lock status and name servers. Answer "who do I contact to manage this domain?"
- HTTP Header Checker See the full HTTP response headers any URL returns — status, redirect chain, content type, caching, compression, cookies and security headers — read live from the server.
- HTTP Status Code Checker Check the exact HTTP status code a URL returns right now — 200, 301, 404, 500 — plus the full redirect chain, read live from the server.
- Redirect Checker Trace every redirect a URL passes through — each hop, its status code (301, 302, 307, 308) and the final destination — to find and collapse slow redirect chains.
- Security Headers Checker Scan a live URL for the HTTP security headers that protect visitors — HSTS, CSP, X-Frame-Options, X-Content-Type-Options and more — scored and explained.
- HSTS Checker Check whether a URL sends an HSTS header and read its policy — max-age, includeSubDomains and preload — to confirm HTTPS is enforced and downgrade-proof.
- Cache Header Checker Inspect how a URL is cached — Cache-Control, Expires, ETag, Last-Modified, Age and Vary — with a plain-English verdict on cacheability, read live.
- Content-Type Checker See the Content-Type a URL returns — the MIME type, the charset and whether nosniff is set — so you can fix wrong types and garbled encodings.
- Server Header Checker Identify the web server behind a URL — the Server and X-Powered-By headers, CDN hints and any version disclosure that fingerprints the stack.
- Gzip / Brotli Compression Checker Check whether a URL is served with gzip or Brotli compression — the Content-Encoding, the compressed vs uncompressed size and the percentage saved.
- Response Time Checker Measure how fast a URL responds and where the time goes — DNS, TCP, TLS, time-to-first-byte and download phases broken down visually.
- Page Size Checker Measure a page's HTML document size — the transfer size on the wire and the decompressed size, with the compression saving, read live.
- Mixed Content Checker Scan an HTTPS page for insecure http:// resources that break the padlock — scripts, styles, images and iframes loaded over http, with block-vs-warn severity.