JWT Token Decoder
Decode JWT tokens instantly. View header, payload, and signature as formatted JSON. Color-coded sections with time field interpretation. Free, client-side.
Why Use the JWT Decoder?
JWT tokens are everywhere in modern web applications for authentication and data exchange. Debugging JWTs requires decoding the Base64-encoded header and payload. Our tool instantly decodes JWTs with color-coded sections and automatic time field interpretation.
Key Features
- Color-coded header (red), payload (violet), and signature (teal) sections
- Automatic interpretation of time fields (iat, exp, nbf) as human-readable dates
- Visual token structure breakdown showing all three parts
- Copy buttons for each decoded section independently
How to Use
- Paste your JWT token in the input area
- The token is automatically decoded into header, payload, and signature
- View formatted JSON output and time interpretations
Technical Details
JWT tokens consist of three Base64URL-encoded parts separated by dots: header.payload.signature. The header specifies the algorithm, the payload contains claims, and the signature is used for verification. This tool only decodes — it does not verify the signature. Base64URL encoding uses - instead of + and _ instead of /, with no padding.
FAQ
Does this tool verify the JWT signature?
No, this tool only decodes the token. Signature verification requires the secret key or public key, which is not provided to a client-side decoder for security reasons.
Is my JWT token sent to any server?
No. All decoding happens entirely in your browser. Your JWT token never leaves your device.
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