JWT Decoder
Decode and inspect JWT tokens with header, payload analysis, and expiration check. Client-side only — your tokens never leave the browser. Free.
No sign-up
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100% free
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Private
Decoder Input
Decoder Header
Decoder Payload
Decoder Claims
Decoder Signature
Decoder Signature Note
Decoder Claims Ref
| Claim | Decoder Full Name | Description |
|---|---|---|
| iss | Issuer | Decoder Claim Iss |
| sub | Subject | Decoder Claim Sub |
| aud | Audience | Decoder Claim Aud |
| exp | Expiration | Decoder Claim Exp |
| nbf | Not Before | Decoder Claim Nbf |
| iat | Issued At | Decoder Claim Iat |
| jti | JWT ID | Decoder Claim Jti |
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JWT Token Decoder and Inspector
The JWT Decoder and Inspector is a free online tool that decodes JSON Web Tokens (JWT) and displays their header, payload, and signature in a human-readable format. Paste any JWT string and instantly see the decoded JSON content of each section, including algorithm, issuer, subject, expiration time, issued-at time, custom claims, and signature verification status. This is an essential debugging tool for anyone working with authentication and authorization systems.A JWT consists of three Base64URL-encoded sections separated by dots: the header (algorithm and token type), the payload (claims like sub, iss, exp, iat, and custom data), and the signature (for verification). The decoder parses each section, pretty-prints the JSON with syntax highlighting, and automatically converts Unix timestamps (exp, iat, nbf) to human-readable dates. The tool also displays whether the token has expired, making it immediately clear if an authentication failure is due to token expiration.Backend developers debug authentication issues by inspecting token contents and expiration times. Frontend developers verify that API responses include the expected claims in the JWT. Security engineers audit token configurations (algorithm, expiration policy, claim contents). QA testers validate that login flows produce correct tokens. DevOps engineers troubleshoot service-to-service authentication in microservices architectures. All decoding runs locally in your browser — your tokens are never sent to any server.JWT Decoder is part of the facilita.tools developer toolkit. Available in Portuguese, English, and Spanish, optimized for desktop and mobile browsers.
Frequently Asked Questions
What is a JWT token?
A JSON Web Token (JWT) is a compact, URL-safe token format used for securely transmitting information between parties. It consists of three parts separated by dots: header (algorithm), payload (claims/data), and signature (verification).
Is it safe to decode JWT tokens online?
Our decoder processes tokens entirely in your browser (client-side JavaScript). No data is sent to any server. However, never paste production tokens containing sensitive data into any online tool. For production debugging, use local tools.
What are common JWT claims?
Standard JWT claims include: 'iss' (issuer), 'sub' (subject), 'exp' (expiration time), 'iat' (issued at), 'aud' (audience), and 'nbf' (not before). Custom claims can contain any application-specific data.