Free Developer Utilities
Format JSON, decode a JWT, test a regex, generate a UUID or hash, or check color contrast — the small tools you reach for a dozen times a day, without pasting secrets into a third-party API.
JSON Formatter
Clean, validate, and explore JSON in an interactive tree.
Base64 / JWT Decoder
Encode, decode, and inspect tokens in the browser.
Regex Tester
Test patterns against sample text with live highlights.
Color & Contrast Checker
Convert HEX/RGB/HSL and check accessible contrast.
Timestamp Converter
Convert between Unix time, ISO 8601, and local dates.
Hash Generator
MD5, SHA-1, SHA-256, and HMAC-SHA256 from text, entirely in your browser.
UUID Generator
Bulk-generate UUIDs or random strings with a custom charset.
HTML Editor
Write HTML/CSS and see a live sandboxed preview, right in your browser.
Safe for tokens, keys, and secrets
The Base64/JWT decoder and hash generator are built to handle sensitive strings — auth tokens, API keys, session payloads. Decoding happens entirely with in-browser JavaScript; nothing is ever sent to a server, which is not something you can assume of every "paste your JWT here" site online.