JWT Decoder
Decode JWT header, payload, and signature for inspection.
How to use
- Paste the JWT into the input field.
- The header and payload are decoded automatically.
- Inspect claims such as exp, iat, and iss.
- Copy any section you want to share or log.
About this tool
JWT Decoder gives developers a quick window into the contents of a JSON Web Token. Paste any token and instantly see the header algorithm, the payload claims, and the signature segment without writing any code.
Features
Automatic Base64URL decoding, pretty-printed JSON for header and payload, expiry validation based on the exp claim, copy buttons for each section, and clear error messages when the token is malformed.
Use cases
Debugging authentication flows in APIs, inspecting tokens produced by identity providers, verifying that the right claims are present during integration tests, and teaching JWT concepts to new team members.
Why choose this tool
Since decoding happens locally, production tokens never leave your machine, which is essential when troubleshooting live systems. The structured layout makes it easy to spot missing or incorrect claims at a glance.
FAQ
- Does it verify the signature?
- No. This tool only decodes the token. Signature verification requires the secret or public key used to sign it.
- Is my token sent anywhere?
- No. Decoding happens entirely in the browser, so tokens are never transmitted to a server.
- Can it highlight expired tokens?
- Yes. If the payload contains an exp claim, the tool shows whether the token is currently valid or expired.