JWT Decoder
Decode a JSON Web Token to inspect its header and claims.
A JSON Web Token packs three Base64 segments — header, payload and signature — into one compact string. This decoder splits it apart and shows the header and claims as readable JSON, including when the token was issued and when it expires.
Handy while building auth
- Check which claims a login flow is actually putting in the token.
- Spot an expired or wrongly-scoped token while debugging a 401.
- Confirm the algorithm and key id without spinning up a backend.
Decoding only reads the token — it does not verify the signature, and your token is processed entirely in the browser, so it is never transmitted.
