All Tools
Every tool on Codeswap, grouped by category — 500 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
43 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.
- 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.
JSON
47 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.
Regex
28 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.
- 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
44 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.
Encoding
40 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.
Text Processing
44 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.
Code Conversion
52 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.
Markdown
35 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.
Color & Design
44 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.
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
49 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.
Web & SEO
41 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.
- 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.