Dev Tools
Free developer tools that run in your browser: format and validate JSON, encode and decode Base64 and URLs, hash text or files with MD5 or SHA-256, decode a JWT and check its signature, and convert Unix timestamps. Nothing you paste is sent to a server.
Pick a tool
JSON Formatter
Dev ToolsFormat, validate and minify JSON with error locations
Base64 Encoder/Decoder
Dev ToolsEncode text to Base64 and decode it back
URL Encoder/Decoder
Dev ToolsEncode and decode URLs for web applications
Hash Generator
Dev ToolsGenerate MD5, SHA-1, SHA-256, SHA-512 and SHA3 hashes of text or files
JWT Decoder
Dev ToolsDecode JWT tokens, read exp/iat/nbf in plain words and check HS, RS, PS and ES signatures with SHA-256, SHA-384 or SHA-512
Unix Timestamp Converter
Dev ToolsConvert Unix timestamps to dates and back. Detects seconds, milliseconds, microseconds and nanoseconds, and converts a whole list at once
Frequently asked questions
Is it safe to paste a token or an API response here?
Every tool on this page runs in your browser and sends nothing you paste to a server, so a token or a customer record stays on your machine. Still treat a live token as a secret: anyone who has it can use it until it expires.
If anyone can decode a JWT, is it secure?
A signed JWT is protected against changes, not against reading. Its header and payload are only Base64url encoded, so anyone holding the token can read them; the signature only proves nobody changed them. Never put a password or other secret in a JWT payload unless the token is encrypted.
Sources: IETF, RFC 7519: JSON Web Token, section 12
What is the difference between Base64 and a hash?
Base64 is an encoding: anyone can turn it back into the original, so it hides nothing. A hash such as SHA-256 is one way: the same input always gives the same hash, but the input cannot be worked out from it. Use Base64 to carry data through text-only channels, and a hash to check that a file has not changed.
Sources: NIST, FIPS 180-4: Secure Hash Standard
What is a Unix timestamp?
The number of seconds since 00:00:00 UTC on 1 January 1970, not counting leap seconds. Many systems store milliseconds instead, so a 13-digit number is usually milliseconds. Unix Timestamp Converter works out whether a number is in seconds, milliseconds, microseconds or nanoseconds.
Sources: The Open Group, POSIX.1-2024, 4.19 Seconds Since the Epoch