What is a JWT? JSON Web Token - a compact token used for authentication & information exchange. Consists of three Base64-encoded parts joined by dots: header.payload.signature.
Parts:
• Header - algorithm & token type
• Payload - the actual data (claims) like user id, expiration
• Signature - cryptographic signature to verify the token
This tool ONLY decodes. It does NOT verify signatures (needs the secret key). Decoding a JWT does not mean the token is valid - only that it could be parsed.
• Paste any JWT into the input field
• Header, Payload and claims appear instantly
• Expiration status shows if token is still valid
• Everything runs locally in your browser - no token leaves your machine
Full Guide →