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HMAC Generator

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Security & Encryption

HMAC Generator

Generate HMAC hashes using SHA256, SHA512, or MD5.

Workspace

Run the tool here

Browser utility

Input

Secret key

Algorithm

Output

Run the workspace to see the response here.

How to use

Enter the message payload.
Provide the shared secret and choose the algorithm.
Compare the signature with the one the sender provided.

About this tool

Create an HMAC signature with a secret key and a chosen hash algorithm, as used by webhooks and APIs.

HMAC Generator is part of the TmpMailer Security & Encryption set — free browser utilities that open instantly, need no account, and pair well with a temporary-email workflow when you just need a quick result.

Common use cases

Verifying a webhook signature.
Debugging an API request signature.
Generating test vectors for an integration.

Common questions

How is HMAC different from a plain hash?

It mixes in a secret key, so only parties who know the key can produce or verify the signature.

Which algorithm should I use?

SHA-256 is the common default. Follow the provider's documentation exactly, including the message format.

Why does my signature not match?

Usually the message was re-encoded, a timestamp was added, or the secret is wrong. Compare the raw bytes, not the rendered string.

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