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JWT Decoder Online
Decode JSON Web Tokens (JWT) to view header, payload, and signature. Check token expiration and validate JWT format. Free, secure, and privacy-first.
jwt
json web token
decoder
authentication
security
token validation
Decoded JWT will appear here
Enter a JWT token above to decode it
About JWT Decoder
This free online tool decodes JSON Web Tokens (JWT) and displays their header, payload, and signature components. All decoding is done in your browser - your tokens never leave your computer.
Features
- Complete JWT Decoding: Decode header, payload, and signature components
- Token Validation: Check if JWT format is valid and detect expired tokens
- Timestamp Conversion: Automatically convert Unix timestamps to readable dates
- Copy & Download: Copy individual components or download complete decoded data
- File Upload: Upload JWT tokens from files
- Auto-decode: Automatically decode tokens as you type
- Privacy First: All processing happens locally in your browser
JWT Components
- Header: Contains metadata about the token, including the signing algorithm
- Payload: Contains the claims (user data, permissions, expiration, etc.)
- Signature: Used to verify the token hasn't been tampered with
Common JWT Claims
- iss (Issuer): Who issued the token
- sub (Subject): Who the token is about
- aud (Audience): Who the token is intended for
- exp (Expiration): When the token expires
- iat (Issued At): When the token was issued
- nbf (Not Before): When the token becomes valid
Security Note
This tool only decodes JWT tokens - it does not verify signatures. Never paste production tokens containing sensitive information into online tools. For signature verification, use server-side validation with the appropriate secret key.
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