JWT Decoder
FreeDecode and inspect JSON Web Tokens to view header, payload, and claims.
Standard JWT Claims
issIssuersubSubjectaudAudienceexpExpiration TimenbfNot BeforeiatIssued AtjtiJWT IDAbout JWT Decoding
JSON Web Tokens (JWTs) consist of three Base64URL-encoded parts: header, payload, and signature. This tool decodes the header and payload to reveal their contents. Note that decoding does not verify the signature - anyone can decode a JWT, but only those with the secret key can verify it. Never share JWTs containing sensitive data, as they can be easily decoded.
How to Use the JWT Decoder
- Paste your JWT token in the input area
- The token is automatically decoded as you type
- View the header (algorithm, type) and payload (claims)
- Check token expiration status and timestamp interpretation
- Copy individual parts as needed
Features
- Real-time JWT decoding
- Header and payload visualization
- Expiration status check
- Timestamp interpretation
- Standard claims reference
- 100% client-side processing
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe means of representing claims between two parties. JWTs are commonly used for authentication and information exchange in web applications.
A JWT consists of three parts separated by dots:
- Header: Contains the token type and signing algorithm
- Payload: Contains the claims (user data, expiration, etc.)
- Signature: Verifies the token hasn't been tampered with
Common Use Cases
- Debugging: Inspect JWT contents during development
- Troubleshooting: Check why authentication is failing
- Security review: Verify token claims and expiration
- Learning: Understand JWT structure and contents
- API testing: Examine tokens from API responses
Security Note
Important: This tool only decodes JWTs - it does not verify signatures. Anyone can decode a JWT to see its contents; the signature verification requires the secret key and is what provides security.
Never share JWTs that contain sensitive information, and always use HTTPS when transmitting tokens. JWTs should have short expiration times and be stored securely.