Can this tool prove a JWT is valid?

No. It decodes readable segments only. Validity requires cryptographic signature verification and claim checks against trusted server configuration.

A typical signed JWT (JWS) is encoded but not encrypted, so its header and payload are readable. Do not place secrets in them.

Which claims should a server validate?

At minimum validate the signature and allowed algorithm, then issuer, audience, expiry, and not-before as applicable. Authorization still needs server-side policy.

What if I pasted a live access token publicly?

Assume it is compromised. Revoke it or end the session, rotate related credentials if needed, and remove it from logs and shared history.

Encoding

JWT Decoder

Inspect JSON Web Tokens

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JWT Decoder how to for jwt decoder: open the tool, run a tiny sample, then save the result.

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JWT Decoder

Paste a JSON Web Token to inspect header and payload. Signatures are not verified here.

Guide & documentation

How to use JWT Decoder

DevsWallet JWT Decoder displays the Base64URL-encoded header and payload of a JSON Web Token so developers can inspect claims such as issuer, audience, subject, issued-at time, and expiry. Decoding is not verification: anyone can create or modify a token-shaped string. An application must verify the signature with an allowed algorithm and trusted key, then validate issuer, audience, expiry, not-before, and any authorization claims on the server. Treat real tokens as credentials and use redacted samples whenever possible.

JWT Decoder runs in your browser on DevsWallet. Use the steps below for a first successful run, then open the full guide if you need deeper examples, FAQs, and troubleshooting.

Step by step

Paste a non-production or redacted token and decode its header and payload.
Check the declared algorithm, key identifier, issuer, audience, expiry, and not-before timestamps.
Do not trust the displayed claims until the receiving service verifies the signature and claim rules.
Remove the token from shared devices and revoke it if it was exposed in logs, screenshots, chat, or source control.

Common use cases

Diagnosing an expired-token or wrong-audience authentication failure.
Converting NumericDate claims into readable times during incident response.
Checking which scopes a test identity received from an authorization server.
Teaching the distinction between token decoding, signature verification, and authorization.

Expert deep dive

JWTs carry claims in header and payload segments without verifying signatures. Inspect exp, iss, and custom claims during API debugging, never trust decoded content without cryptographic verification server-side.

Frequently asked questions

Can this tool prove a JWT is valid?: No. It decodes readable segments only. Validity requires cryptographic signature verification and claim checks against trusted server configuration.
Is a JWT encrypted?: A typical signed JWT (JWS) is encoded but not encrypted, so its header and payload are readable. Do not place secrets in them.
Which claims should a server validate?: At minimum validate the signature and allowed algorithm, then issuer, audience, expiry, and not-before as applicable. Authorization still needs server-side policy.
What if I pasted a live access token publicly?: Assume it is compromised. Revoke it or end the session, rotate related credentials if needed, and remove it from logs and shared history.