JWT Decoder

What is JWT Decoder?

JWT Decoder separates a JSON Web Token into its encoded header and payload so claims such as issuer, audience, subject, and expiry can be inspected. It supports authentication debugging when a token is present but an API rejects it or application behavior does not match the contained claims.

How to use JWT Decoder

Paste the JWT token and inspect the decoded header, payload, and claims without manually splitting or decoding the token.

When is JWT Decoder useful?

JWT Decoder is useful when debugging authentication, checking token claims, inspecting expiration values, or verifying what information a JWT contains.

Example

A practical example is decoding a development access token to inspect its subject, role, and expiration claim.

Practical notes

Decoding does not verify the signature and does not prove that a token is trustworthy. Treat tokens as credentials, avoid sharing production values, check expiry and audience carefully, and use a trusted server-side library with the expected algorithm and key for verification.