What can a JWT decoder show?

It decodes the token's header and payload so you can inspect claims such as issuer, subject, audience, and expiration.

Does decoding verify the signature?

No. Base64url decoding is not authentication. Use the issuing service and its trusted key to verify a JWT before relying on its claims.

Is my token sent to a server?

No. Decoding happens locally in your browser. Treat tokens as secrets and clear them after inspection.

JWT Token Decoder

Decode and analyze JSON Web Tokens (JWT) safely in your browser.

Encoded Token

Token String

Quick Samples

Signature Verification

HMAC Secret (for HS256/HS384/HS512)

JWKS URL (for RS256/ES256)

Client-side fetch; CORS must allow the request.

JWT Scenarios & Examples

Standard Access Token

A typical authenticating token with subject, issuer, and expiration.

{
  "sub": "1234567890",
  "name": "John Doe",
  "iat": 1516239022,
  "exp": 1516242622,
  "iss": "https://auth.example.com"
}

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Validate HS256 and RS256 JWT signatures plus exp, nbf, aud and iss claims — client-side, pairs with JWT Decoder.

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The best free, browser-based developer tools compared — CyberChef, Regex101, JWT.io, and the privacy-first alternatives. What to use for JSON, regex, JWTs, hashing, UUIDs, and more.