JWT Decoder
Online JWT decoding and verification tool
Overview
A professional JWT Token parsing tool that quickly decodes JSON Web Tokens into their component parts. It clearly displays Header, Payload, and Signature information, and automatically checks whether the token has expired, helping developers efficiently debug authentication endpoints.
Features
- JWT token parsing & decoding
- Header/Payload/Signature breakdown
- Expiration time checking
- Base64URL decoding
- Token validity verification
- JSON formatted display
- Algorithm type identification
How It Works
- Paste the complete JWT Token into the input area
- The tool automatically splits the token into Header, Payload, and Signature
- Review the Base64URL decoded results for each section
- Check the expiration time (exp field) in the Payload
- Copy the decoded JSON data for debugging
Tips
- Paste the token with all three parts intact (separated by two dots)
- Check the exp field to quickly determine if the token is still valid
- Copy the decoded payload to a JSON formatter for deeper analysis during debugging
FAQ
What are the three parts of a JWT?
The Header contains the algorithm type, the Payload holds claim data, and the Signature is computed from the first two parts to verify token integrity.
Does the tool verify the signature?
Currently it only decodes and displays token content without performing signature verification, which requires the server secret and cannot be done in the browser.
Why does some token data appear garbled?
JWT uses Base64URL encoding. If the token format is non-standard or truncated, decoding may be incomplete. Ensure the token is fully copied.