JWT Decoder
Decode JWT headers and payloads locally, inspect claims, and check expiration details quickly.
This tool decodes the header and payload locally in your browser. It does not verify the signature or confirm that the token is trustworthy.
signature
About the jwt decoder
How this tool works
JWTs are often easy to inspect but annoying to decode by hand, especially when you just want to verify a claim or timestamp quickly. This tool makes that browser workflow faster.
The output keeps the header, payload, and signature segment separate so it is easier to reason about what the token contains and what it does not prove.
Where it is useful
It is useful during API debugging, auth troubleshooting, webhook inspection, and local development work.
The tool stays client-safe and explains its limits clearly, which is a better fit than pretending it performs signature verification.
- Inspect claims during auth, API, and webhook debugging.
- Check exp, sub, aud, or custom fields without decoding manually.
- Compare token payloads quickly while troubleshooting environment issues.
Example workflows
3 examplesValid JWT
Decoded header, payload, and signature segments
JWT with exp
Expiration timestamp and expired state become visible
Malformed token
Clear error instead of a broken output panel
Common uses
3 ideas- Inspect claims during auth, API, and webhook debugging.
- Check exp, sub, aud, or custom fields without decoding manually.
- Compare token payloads quickly while troubleshooting environment issues.
FAQ
3 answersWhat does the JWT decoder actually do?
It decodes the Base64URL header and payload, then parses the JSON claims so you can inspect them directly in the browser.
Does decoding a JWT verify that it is valid?
No. This tool does not verify the signature or confirm trust. It is meant for inspection and debugging, not token validation.
How does the decoder handle expiration data?
When the payload includes an exp claim, the widget converts it into an ISO timestamp and marks whether the token appears expired.