Decodes the header and payload of a JWT and reports the algorithm and expiry. It deliberately does not verify the signature — that needs the key — and says so, because a tool that looks like it validates while only decoding is worse than none.
Runs entirely in your browser
A JSON Web Token (JWT) packs a header and a payload of claims into a compact, URL-safe string, used widely for authentication and API access. This tool decodes the header and payload so you can read the claims, the signing algorithm and the expiry time.
It is deliberately clear about one thing: it decodes but does not verify the signature. Verifying requires the secret or public key, which you should never paste into a web page, and a tool that appears to validate while only decoding would be worse than none — it could lull you into trusting a forged token. So it reads the contents and tells you it has not checked authenticity.
Decoding runs in your browser, so the token — which may be a live credential — is not uploaded. Use it to inspect what a token contains, check an expiry, or debug an auth flow, while remembering the payload is readable to anyone and must not hold secrets.
TechToolsHQ is an independent, reader-supported tech platform. If this free tool saved you time, solved a problem, or helped your workflow, consider supporting our work. Your support helps us keep our utilities 100% free, private, and ad-free for everyone.