Introducing JWT Decoder | Tools.Town Blog

JWT Decoder is now live on Tools.Town — a developer tool that decodes JSON Web Tokens and displays the header, payload, and standard claims in human-readable format, with expiry status and optional signature verification.

Paste a JWT from your API response, auth header, or cookie, and instantly see what’s inside.

What Does It Do?

Header & Payload

Decodes all three JWT sections. Header shows algorithm and type; payload shows all claims in formatted JSON.

Expiry Status

The exp claim is converted to a readable date, with a clear ACTIVE or EXPIRED badge.

Verification

Optionally paste your secret or public key to verify the token's signature is authentic.

All decoding happens in your browser. Your JWT is never sent to any server — only you can see it.

How It Works

Paste JWT

Paste a JWT (three base64url segments separated by dots) into the input field.

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Read the payload

The header and payload are decoded and displayed as formatted JSON. Standard claims are labeled.

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Verify (optional)

Add your signing secret or public key to verify the signature matches the payload.

Why We Built It

Debugging authentication issues in APIs means inspecting the JWT to see what claims it carries. The encoded token is unreadable. JWT Decoder makes the contents visible in two seconds — expiry date, user ID, roles, scopes — without needing curl, a language runtime, or a decode function in your app.

Try It Now

Free Tool

No sign-up In-browser

JWT Decoder

Decode JSON Web Tokens and inspect header, payload, and expiry. Optional signature verification with your secret.

Header & payloadExpiry statusStandard claim labelsSignature verification

Decode JWT

Also useful: JWT Generator to create tokens for testing, and more developer tools.

Frequently Asked Questions

Does JWT Decoder verify the signature?

The decoder splits and base64-decodes the JWT to show the payload. Full signature verification requires the secret/public key, which the tool supports in verification mode.

Is it safe to paste my JWT here?

Decoding happens entirely in your browser — the JWT is never sent to any server. That said, avoid pasting production tokens in shared or untrusted environments.

What claims does it highlight?

Standard claims like iss (issuer), sub (subject), exp (expiry), iat (issued at), and aud (audience) are labeled and the exp field shows a human-readable date with expired/active status.

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Introducing JWT Decoder — Now Live on Tools.Town