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JWT Inspector & Verifier

SubtleCrypto Verifier

Inspect JSON Web Tokens, evaluate claims, track expiration validity, and verify HMAC signatures locally via Web Crypto Subtle without transmitting credentials.

Client-Side Cryptography: JWTs and secrets never leave your browser

Encoded JWT Token

HMAC Signature Verification

Decoded (Signature Unverified)

Active / Valid Exp

Header:

{
  "alg": "HS256",
  "typ": "JWT"
}

Payload Claims:

{
  "sub": "usr-9982",
  "name": "Alex Chen",
  "role": "admin",
  "iss": "auth.platform.io",
  "exp": 1999999999,
  "iat": 1680000000
}

How to inspect and verify JWT tokens

1Paste your encoded JWT token into the editor.
2Inspect decoded header and payload claims.
3Optionally provide your HMAC secret to mathematically verify the signature.

Frequently Asked Questions

Are secrets sent to a backend?

No. Cryptographic verification runs entirely via the browser Web Crypto Subtle API.