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JWT Decoder Online Free — PrivaTools

TL;DR: Paste a JWT and see its header, payload, and signature decoded as readable JSON — claims (exp, iat, sub) highlighted. Stays in your browser.

Decode a JWT online for free — paste any JSON Web Token and instantly see its header, payload, and signature decoded as readable JSON. Highlights expiry, algorithm, and standard claims. All decoding happens in your browser; tokens never leave.

JWT Decoder is part of PrivaTools — a free, open-source alternative to iLovePDF, Smallpdf, and Adobe. Server-side tools process your file in an isolated container and discard it immediately; many tools never upload at all and run entirely in your browser.

How to Use JWT Decoder

  1. Paste your JWT — Copy the full token (three dot-separated base64url segments) into the input area.
  2. Inspect the decoded structure — Header, payload, and signature are decoded in your browser. Standard claims (iss, sub, aud, exp, iat, nbf, jti) are highlighted; expiry status is shown.
  3. Copy decoded values — Click Copy on any section to grab the JSON. Decoding never sends your token to a server.

Frequently Asked Questions

Is it safe to paste a real production JWT here?

Yes — decoding happens entirely in your browser using JavaScript's atob(). No part of the token is sent to a server. Verify by checking DevTools → Network.

Can it verify the signature?

Not in this tool. Verification requires the issuer's signing key (HMAC secret for HS*, public key for RS*/ES*). The decoder displays the signature for inspection but doesn't validate it.

What if my JWT is malformed?

If the three-part dot structure is wrong, you'll see a clear error. If the base64 is malformed, the parser shows which segment failed.

Last reviewed 2026-02-15 by the PrivaTools maintainers. Source code on (MIT-licensed, self-hostable).

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