Security & Crypto Tools
HMAC Generator
Compute HMAC-SHA256/384/512 signatures for messages and keys.
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What is HMAC?
An HMAC generator: combine a message with a secret key to produce a keyed hash used to authenticate API requests, webhooks, and messages.
How it works
Web Crypto imports the key material and signs the message with the HMAC algorithm you select; the signature is returned as hex.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Authenticating messages
Generate an HMAC-SHA256 signature for a message with a shared key — the technique behind signed webhooks and API requests.
Common mistakes
Key and message order
HMAC is keyed — swapping key and message changes the result. The tool labels both inputs clearly.
Frequently asked questions
Which HMAC variants are supported?
HMAC-MD5, HMAC-SHA1, HMAC-SHA256, and HMAC-SHA512.
What's HMAC used for?
Verifying message integrity and authenticity when both sides share a secret key.