HMAC Generator

Generate HMAC signatures with SHA-1, SHA-256 or SHA-512.

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How to use HMAC Generator

Three quick steps — no sign-up needed

  1. Step 1

    Enter message and secret key

    Provide the payload string and the shared secret used for authentication.

  2. Step 2

    Choose the algorithm

    Select SHA-1, SHA-256, or SHA-512 for the HMAC construction.

  3. Step 3

    Copy the HMAC hex

    Use the result to verify API signatures - keep secrets out of public pages when possible.

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About HMAC Generator

HMAC Generator builds a Hash-based Message Authentication Code from a message and secret key using SHA-1, SHA-256, or SHA-512. Developers searching "HMAC SHA-256 online" or "HMAC signature generator" need to debug webhook and API auth signatures.

Enter the message, secret, and algorithm, then copy the hex HMAC. HMAC proves integrity and authenticity only when the secret stays confidential and comparison is done in constant time on the server.

Prefer SHA-256 or SHA-512 over SHA-1 for new designs. Never embed production secrets in client-side code or public gists.

Encoding details (UTF-8 vs raw bytes, hex vs base64 output) must match the API docs exactly or signatures will fail.

A development helper - production verification belongs in your backend libraries.

Benefits of HMAC Generator

SHA-1 / 256 / 512 options Match common API requirements.
Message + key inputs Full HMAC control in the browser for tests.
Hex output Easy to compare with documented examples.
Webhook debugging Reproduce signatures from vendor docs.

Frequently asked questions

What is HMAC?

A keyed hash that authenticates a message with a shared secret.

Is HMAC encryption?

No - it authenticates; it does not hide message contents.

Which algorithm should I pick?

Follow the API. New systems typically use SHA-256 or SHA-512.

Why does my signature not match?

Different encoding, newline characters, or key format are common causes.

Should I paste live production secrets here?

Avoid when possible; use local tools for sensitive keys.