JWT Tools
JWT Tools
Decode JSON Web Tokens and inspect the header, payload, and signature claims; encode new tokens; view JWKS; reference standard claims; verify signatures; run security tests.
JWT Tools
Decode JSON Web Tokens and inspect the header, payload, and signature claims; encode new tokens; view JWKS; reference standard claims; verify signatures; run security tests.
Common uses
- Decode a JWT from an Authorization header
- Build and sign a new HS256 token
- Check if a token has expired
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- compare two jwts
- jwt alg none test
- jwt claims reference
Frequently asked questions
How do I decode a JWT?
Paste the token and the header, payload, and signature are decoded and displayed instantly. Registered claims are explained inline against RFC 7519 and OpenID Connect.
Can I verify a JWT signature?
Yes. Provide the secret (HMAC) or public key / JWKS (RSA/EC) and the tool reports whether the signature is valid.
Are my tokens sent anywhere?
No. Decoding and verification run locally in your browser; tokens never leave your machine.
How do I decode a JWT without sending it to a server?
Paste the token into the Decode tab to see its header and payload. Decoding happens in your browser.
How do I check whether a JWT has expired?
The decoder shows the exp claim as a readable date so you can see if the token is expired.
Can I compare two tokens or test for the alg none issue?
The Diff tab compares two JWTs and the Security Test tab runs checks such as forged-token tests.
Is my data uploaded to a server?
No. This tool runs entirely in your browser — your input is processed locally on your device and is never uploaded or stored on a server.