Developer Tools
Fast, private developer utilities — JSON, encoding, hashing, color, CSS, generators, formatters and reference cheatsheets. Everything runs client-side in your browser, so your code and data never leave your device.
A fast, private toolbox for developers: format and validate JSON, YAML and XML; encode and decode Base64, URLs and JWTs; generate hashes, UUIDs, passwords and mock data; convert colours; build CSS; and reach for a reference cheatsheet when you need one. No tab-switching across a dozen different sites — they are all here, and all instant.
Because every tool runs client-side, your code, tokens and payloads never leave the browser. That makes it safe to paste a production JSON blob, a JWT or an API response without it being uploaded to a third-party server. No sign-in, no rate limits, and no telemetry on the data you process.
Start here — our most useful developer tools
Hand-picked from the full collection of 1599 tools.
JSON Formatter & Validator
Pretty-print, minify and validate JSON — the everyday workhorse, safe for production payloads because nothing is uploaded.
Regex Tester with Plain-English Explainer
Live regex matching with a plain-English explanation of what your pattern actually does.
UUID Generator
RFC-compliant version-4 UUIDs, one at a time or in bulk.
Base64 Encoder
Standard or URL-safe Base64, encoded entirely in your browser.
CSS Gradient Generator
Linear and radial CSS gradients with a live preview and copy-ready code.
Browse developer tools by topic
- API Key Setup Documentation Builder
- Barcode Generator (EAN / Code 128 / Code 39 / UPC)
- CHANGELOG Entry Generator
Frequently asked questions
Is it safe to paste sensitive data like JWTs or API responses?
Yes. Every developer tool processes data entirely in your browser — nothing is uploaded, stored or logged — so pasting a token, secret or production payload is as safe as running the code locally.
Do the tools work offline?
Once a tool page has loaded it runs without a network connection, because the processing happens in your browser rather than on a server.
Are there usage or size limits?
There are no artificial rate limits or account gates. The only practical limit is your device's memory, since large inputs are processed in-browser.
Which formats and encodings are supported?
JSON, YAML, TOML, XML, CSV/TSV and SQL formatting; Base64, Base32, Base58 and URL/HTML encoding; MD5, SHA and HMAC hashing; plus JWT, UUID/ULID and many more.