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Need to inspect a JWT token? This free online JWT decoder lets you decode JSON Web Tokens instantly, showing the header, payload, and expiration status — all without sending your token to any server.
On this page
How to Use This JWT Decoder#
- Paste your JWT token into the input field
- Click Decode JWT to see the header and payload
- Check the expiration status shown below the decoded data
- The signature is displayed but not verified (that requires the secret key)
What is a JWT (JSON Web Token)?#
A JWT is a compact, URL-safe token format used for authentication and information exchange. It consists of three Base64-encoded parts separated by dots: Header (algorithm), Payload (claims/data), and Signature (verification).
Common JWT Claims#
sub— Subject (user ID)iat— Issued At (timestamp)exp— Expiration Time (timestamp)iss— Issueraud— Audiencenbf— Not Before
When to Decode JWTs#
- API debugging — inspect token contents during development
- Auth troubleshooting — check if tokens are expired or have wrong claims
- Security audits — verify tokens don’t contain sensitive data
Security Notice#
This tool runs 100% in your browser. Your JWT tokens are never sent to any server. However, never paste production tokens with sensitive data into tools you don’t trust — this one is safe because it’s fully client-side.
Recommended Reading#
Essential resources for working with JWTs and API security:
- API Security in Action — essential reading for JWT and API authentication
- OAuth 2 in Action — essential reading for token-based auth
- Web Application Security — essential reading for securing web apps
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