JWT Decoder
A free online tool to decode and analyze JSON Web Tokens (JWT). Paste your JWT to instantly see the decoded header, payload, and signature parts.
Paste your JWT token to decode its contents (header, payload, and signature).
Typical Use Cases
JWT Decoder is essential for developers working with JSON Web Tokens in their applications. During development and debugging, it allows quick inspection of token contents without writing code. This is particularly useful when troubleshooting authentication issues, verifying that tokens contain expected claims, or understanding the structure of tokens issued by third-party services.
Security professionals also use JWT decoders to audit tokens for potential vulnerabilities. By examining the header, you can verify the signing algorithm being used. The payload inspection helps to ensure sensitive information isn't being improperly stored in tokens. While our decoder doesn't verify signatures cryptographically, it separates the signature component for reference, making it easier to understand the complete token structure.
JWT Structure
- Header: Contains token type and the signing algorithm being used
- Payload: Contains the claims (data) being transmitted in the token
- Signature: Used to verify the token hasn't been tampered with
- Format: JWT is formatted as Header.Payload.Signature, where each section is base64url encoded