Paste a token above to inspect the signature.
How to Use JWT Decoder
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1. Paste a JWT Token
Copy a JWT token from your app, API client, or browser dev tools and paste it into the input field.
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2. View the Decoded Parts
The tool splits the token into its header, payload, and signature sections and decodes the base64 data.
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3. Review the Claims
Inspect the algorithm, issued-at time, expiry, and any custom claims in the decoded payload.
The Technical Details
This interactive web utility provides fast, reliable, and completely private data transformations. In modern workflows, quick formatting, conversions, or estimations are essential. By running all logic entirely in your browser with client-side JavaScript, this tool guarantees that your data never leaves your machine. This approach delivers maximum performance and absolute data privacy, as no information is ever sent to a server.
Frequently Asked Questions
What is a JWT?
A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. It has three base64-encoded parts: header, payload, and signature.
Is it safe to paste my token here?
The tool only decodes, and does not verify the signature. Never paste production tokens that grant privileged access into any online tool.
Is my token sent to a server?
No. Decoding runs in your browser; nothing is transmitted anywhere.
Where is the algorithm listed?
The signing algorithm (e.g. HS256, RS256) is in the decoded header under the 'alg' key.