Free tools for developers
UUID generators, JSON formatters, JWT decoders and more — fast, free, and 100% private. Every tool runs locally in your browser; your data never touches a server.
Generators
JSON
JSON Formatter
Format, validate and minify JSON online with instant error detection.
JSON Validator
Validate JSON syntax online with exact line and column error reporting.
JSON Diff
Compare two JSON documents and see exactly what was added, removed or changed.
JSON Minifier
Minify JSON online and see exactly how many bytes you saved.
JSON to CSV
Convert a JSON array of objects into a downloadable CSV file.
CSV to JSON
Convert CSV into a clean JSON array, with type inference and nested keys.
Encoding
Date & Time
Security
JWT Decoder
Decode JSON Web Tokens and inspect header, payload and signature.
JWT Generator
Build and sign a JSON Web Token from a custom header, payload and secret.
JWT Inspector
Decode a JWT, verify its HMAC signature, and surface common security issues.
JWT Expiration Checker
Check if a JWT is expired with a live countdown to (or since) its exp claim.
JWT Claims Viewer
See every JWT claim explained in plain English, standard vs. custom.
Hash Generator
Generate MD5, SHA-1, SHA-256 and SHA-512 hashes from text.