JWT Decoder

Decode and inspect JSON Web Tokens (JWTs) instantly. View header, payload, and signature without a secret key. Debug authentication tokens safely.

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JWT Token

How to Use JWT Decoder

1

Paste your JWT

Copy your JWT token (the three-part dot-separated string) and paste it into the input field.
2

Inspect decoded sections

The tool splits the JWT into Header, Payload, and Signature, formatting each as readable JSON.
3

Check claims and expiry

Review standard claims like iss, sub, aud, exp, and iat. Expiry times are shown in human-readable format.

Frequently Asked Questions

Can this tool verify a JWT signature?

JWT decoding (reading the payload) requires no secret. Signature verification requires the secret or public key, which is not supported here for security reasons. This tool is for inspection and debugging only.

Is it safe to paste my JWT here?

All decoding happens in your browser — the token is never sent to any server. However, be cautious pasting production tokens in shared or monitored environments.

What is the exp claim?

The exp (expiration) claim is a Unix timestamp indicating when the token expires. This tool converts it to a human-readable date and flags whether the token has expired.

Does it support all JWT algorithms?

JWT decoding does not require knowledge of the algorithm. The header and payload are simply Base64Url decoded, so this tool works with HS256, RS256, ES256, and any other algorithm.

About JWT Decoder

The JWT Decoder instantly breaks apart a JSON Web Token into its three components: the Header (algorithm and token type), the Payload (claims), and the Signature. This is invaluable when debugging authentication flows, inspecting OAuth tokens, or verifying that a token contains the expected user claims and permissions.

Standard JWT claims such as subject (sub), issuer (iss), audience (aud), and expiry (exp) are displayed with clear labels, and expiry timestamps are converted to human-readable date and time. Since JWTs are merely Base64Url-encoded, no secret key is needed for decoding — the tool works entirely client-side with no data transmission.

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