JWT Decoder
Decode JSON Web Tokens (JWT) to see header and payload. Check expiration time, issued-at, and all claims. No data sent to servers.
How to Use JWT Decoder
- Paste your JWT token into the input field.
- The header and payload are decoded instantly.
- View all claims including expiration (exp), issued at (iat), and subject (sub).
- Check if the token is expired with the visual indicator.
- Copy decoded header or payload as JSON.
Frequently Asked Questions
What is a JWT token?
A JSON Web Token (JWT) is a compact, URL-safe token format used for authentication. It contains a header (algorithm info), payload (claims/data), and signature.
Can this tool verify JWT signatures?
This tool decodes and displays JWT contents. Signature verification requires the secret key or public key, which should be done server-side.
Is it safe to paste my JWT here?
Yes, all decoding happens in your browser. No data is sent to any server. However, never share production JWTs publicly.
What are JWT claims?
Claims are statements about the user and metadata. Common claims include 'sub' (subject), 'exp' (expiration), 'iat' (issued at), and 'iss' (issuer).