JWT Decoder

When to use JWT Decoder

You paste a 900-line JWT response from an Okta authentication flow into jwt.io and your laptop fan kicks on. This tool decodes the token right in your browser tab — header, payload, and signature laid out side by side — using the Web Crypto API with no server call. Check the `exp` timestamp as a real date, verify the `iss` claim matches the expected issuer, and inspect which scopes and roles are actually encoded before you spend an hour debugging permissions. Nothing you decode leaves this tab, which matters: a valid JWT can be replayed immediately, so pasting one into a third-party tool carries real risk. Decode it here, check what you need, move on.

• Verify the issuer and expiry of an Okta token during an auth debugging session
• Check which scopes are encoded before filing a permissions bug report
• Inspect a Cognito token without sending it to an external decoder

About this tool

Debugging an auth issue and you need to know what's actually inside a JWT — who issued it, when it expires, what claims it carries? Paste the token and see the header, payload, and signature decoded side by side. Inspect expiry timestamps as readable dates, check the algorithm, verify the issuer claim without firing up a console. Optionally verify the signature against a public key using the Web Crypto API. Your token never leaves this browser tab — no server receives it, which matters because a valid JWT can be replayed. Decode, inspect, move on.