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JWT Decoder - Free JSON Web Token Decode Online
Decode and verify JSON Web Tokens with this free online JWT decoder. Inspect JWT header payload and signature structure, validate token claims, and analyze JWT format. Perfect for developers debugging JWT authentication. Fast browser-based tool with no data sent to servers.
Waiting to decode JWT Token
Enter JWT Token on the left and click the decode button to view Header, Payload, and Signature details
Header•Payload•Signature
How to Use JWT Decoder
Quick Start Guide
1
Paste your JWT token (starts with 'eyJ...') into the input field.
2
Tool automatically decodes and displays header, payload, signature.
3
Inspect header for algorithm and payload for user data/expiration.
4
Verify signature and copy decoded results if needed.
💡Pro Tips
✓Never share sensitive information in JWT payload as it's only Base64 encoded, not encrypted
✓Always verify the signature before trusting the token contents
✓Check the 'exp' claim to ensure the token hasn't expired
✓Use HTTPS when transmitting JWT tokens to prevent interception
Frequently Asked Questions
JWT (JSON Web Token) is an open standard (RFC 7519) for securely transmitting information between parties as a JSON object. It consists of three parts: header, payload, and signature.
JWT authentication works by encoding user information in a token that's signed by the server. When a user logs in, the server generates a JWT and sends it to the client. The client includes this token in subsequent requests, and the server verifies it to authenticate the user.
JWT is secure when properly implemented. The signature prevents tampering, but the payload is only Base64 encoded (not encrypted). Always use HTTPS, verify signatures, avoid storing sensitive data, and set appropriate expiration times.
OAuth is an authorization framework, while JWT is a token format. JWT can be used as the access token in OAuth 2.0 flows. OAuth defines how to obtain and use tokens, while JWT defines the token structure.
JWT tokens are stateless and cannot be directly revoked once issued. To implement revocation, you need to maintain a blacklist of revoked tokens or use short-lived tokens with refresh tokens.
Common JWT signing algorithms include HS256 (HMAC with SHA-256), RS256 (RSA with SHA-256), ES256 (ECDSA with SHA-256), and PS256 (RSA-PSS with SHA-256). Choose based on your security requirements and infrastructure.
Still have questions? Check out our other tools or contact us for support.