A JSON Web Token (JWT) is a compact, URL-safe token format for transmitting claims between parties. It has three parts separated by dots: a Base64URL-encoded header, a Base64URL-encoded payload, and a signature.

Is my token sent to a server?

No. All decoding happens in your browser using Base64URL decoding. Your JWT never leaves your device.

Can this tool verify the signature?

No. Signature verification requires the secret key or public key. This tool only decodes the header and payload for inspection — never trust unverified tokens in production.

What claims should every JWT have?

iss (issuer), sub (subject), aud (audience), exp (expiration time), iat (issued at). The exp claim is especially important for security.

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JWT Decoder

Decode and inspect JWT tokens — header, payload, and signature — without any server round-trip.

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About this tool

Paste any JWT (JSON Web Token) to instantly decode its header and payload. Displays token structure, expiry time, issued-at time, and all claims in formatted JSON. Signature verification is not performed — this is a decode-only inspector.

How to use

1 Paste your JWT token into the input field.
2 The header and payload are decoded and displayed as formatted JSON.
3 Check the exp field to see when the token expires.
4 Copy individual claims as needed.

Frequently Asked Questions

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