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JWT Verify (HS256)

Verify a JWT's HMAC-SHA256 signature using your secret — locally, so the secret never leaves your browser.

Verifies an HS256-signed JWT's signature using your secret, confirming whether the token is valid and hasn't been tampered with.

How to use JWT Verify (HS256)

  1. Paste the JWT.
  2. Enter your HS256 secret.
  3. View the signature verification result (valid / invalid).

Frequently asked questions

Is the secret sent anywhere?

No. Verification runs entirely on your machine — all processing runs right in your browser, so no data is ever sent to any server.

Related tools

JWT Decoder Decode the header and payload of a JSON Web Token. Warns about expiration. Does not verify the signature (offline). JWT Builder (HS256) Create and sign a JWT with HMAC-SHA256 — handy for generating test tokens. Signing happens locally. Hash (SHA) Compute SHA-1/256/384/512 hashes using the Web Crypto API, entirely on your device. Base64 Encode/Decode Encode/decode Base64 with full UTF-8 support (works correctly with any language). Password / Token Generate strong passwords and secret tokens (API keys, NEWS_INGEST_TOKEN, etc.) using secure crypto — nothing leaves your browser. MD5 Hash Compute the MD5 checksum of text (pure JS implementation, since Web Crypto doesn't support MD5).
🔒 JWT Verify (HS256) runs entirely in your browser — the data you enter is not sent to any server. Free, no sign-up required. See145 free dev tools more.