Developer tools that actually work in your browser

• LLM Tools OpenAI Token Counter Count tokens for GPT-4o, GPT-4, GPT-3.5, o1, o3 with cost estimates.
• LLM Tools Claude Token Counter Count tokens for Claude 3.5 Sonnet, Opus, Haiku, and Claude 4.x.
• LLM Tools Gemini Token Counter Count tokens for Gemini 1.5 Pro, Flash, and Gemini 2.x.
• Crypto & Hashing JWT Decoder Decode, verify, and generate JWTs. HS256, RS256, ES256, EdDSA support.
• JSON JSON Formatter & Validator Format, validate, and minify JSON. Strict and loose parsing modes.
• JSON JSON to TypeScript Generate TypeScript interfaces from JSON with deep nested type inference.
• Code Conversion cURL Converter Convert cURL commands to Python (requests/httpx), JavaScript (fetch), Go, and PHP.
• Regex Regex Tester Test regular expressions against text. PCRE, JavaScript, and Python flavors.
• LLM Tools LLM API Cost Calculator Estimate per-call and monthly costs across LLM providers.

Why these tools, why this site

Most "online tools" sites either bury the actual tool under three pop-ups and an ad wall, or they ship a single-purpose page that's been copy-pasted across fifty domains. Both patterns waste your time. Codeswap is built on a different default: the tool you came for loads in under a second, runs entirely in your browser, and never sends what you paste anywhere. The supporting content exists for context — not to bury the tool you came for.

Every page on this site is opinionated where it can be. The OpenAI Token Counter uses the real tiktoken via WebAssembly, not a regex approximation. The JWT Decoder verifies signatures across HS256, RS256, ES256, and EdDSA — and warns you when a token uses alg:none or an expired claim. The model database tracks 25+ frontier and open-weight models with current pricing, context windows, and benchmark scores. Comparisons are generated from real data, not templated boilerplate.

The site is funded by Google AdSense (when approved) and the long-term plan is to keep the tools themselves free. If a tool becomes substantial enough to warrant a paid tier, the free version stays functional. See the About page for the operator's name and contact details.

Browse by category

A current, hand-maintained reference of every major LLM with pricing, context window, capabilities, and benchmark scores. Use it to pick a model for a workload, to estimate per-call cost, or to compare two models head to head.

• GPT-5OpenAI flagship — $1.25/M input, 400K context
• Claude Sonnet 4.6Anthropic workhorse — $3/M input, 200K context
• Gemini 2.5 ProGoogle flagship — $1.25/M input, 2M context
• DeepSeek-V3Open weights — $0.27/M input
• Llama 3.3 70BOpen weights — $0.59/M input on Together
• Qwen3-Coder-480BOpen code model — $2/M input

How the tools work

Every tool on Codeswap is a static HTML page with a JavaScript front-end. When you load one, you get the full interface and content immediately. When you click "run," the computation happens in your browser — token counters use the real WebAssembly tokenizer for each provider, the JWT decoder uses the WebCrypto API for signature verification, JSON tools use the browser's native parser.

Nothing about your input is sent to a server. You can verify this in your browser's DevTools network tab. This matters because developers paste sensitive things into these tools — API responses, production JWTs, customer PII inside JSON dumps. A tool that leaks any of those is worse than no tool at all.

Programmatic SEO pages — model pages, comparisons, "best LLM for X" pages — are server-rendered from a MySQL database of model specs and benchmark scores. The data behind each comparison is real; the prose around it is hand-written or AI-drafted then edited, never auto-published. If you see an error on a model page, the "report inaccuracy" link in the footer goes straight to the maintainer.