HMAC Generator
Generate HMAC message authentication codes
HMAC Generator is a free online tool from BrowserUtils that generate hmac message authentication codes. It runs entirely in your browser — your data never leaves your device. No account required.
Algorithm:
How to use HMAC Generator
- 1 Paste or type your input into the editor above.
- 2 The tool processes your data instantly — right in your browser, with nothing sent to a server.
- 3 Copy the result with one click or continue editing your input.
About HMAC Generator
Free online HMAC generator. Create HMAC-SHA256, HMAC-SHA512, and other keyed-hash message authentication codes using the Web Crypto API. This tool runs entirely in your browser — your data is never sent to a server. Just paste your input, get instant results, and copy with one click. No sign-up or installation required.
HMAC Generator specs
- Runtime
- 100% client-side (browser)
- Built on
- Web Crypto API (SubtleCrypto) for hashing and crypto.getRandomValues for secure randomness
- Cost
- Free — no account, no rate limits, no usage caps
- Browser support
- Chrome 90+, Firefox 88+, Safari 14+, Edge 90+
- Part of
- 299 developer tools on BrowserUtils (100% client-side)
Questions
What is HMAC?
HMAC (Hash-based Message Authentication Code) combines a secret key with a hash function to produce a code that verifies both data integrity and authenticity.
Which algorithm should I use?
SHA-256 is the most commonly used. SHA-512 provides extra security for sensitive applications. SHA-1 is considered legacy and should be avoided for new projects.
HMAC vs plain hash: what is the difference?
A plain hash only verifies data integrity (the data was not changed). HMAC also verifies authenticity (the data came from someone who knows the secret key). Without a secret key, anyone can compute a plain hash.
Where is HMAC used in practice?
HMAC is used in API authentication (e.g., AWS Signature V4), webhook signature verification, JWT signing (HS256), and secure cookie signing.
Is my secret key safe when generating HMAC online?
Yes, the HMAC is computed entirely in your browser using the Web Crypto API. Your secret key and message data never leave your device.
How do I verify a webhook signature with HMAC?
Paste the webhook payload as the message and the signing secret provided by the service as the key. If the generated HMAC matches the signature in the webhook header, the payload is authentic.
Comments
Related tools
More Hashing & Crypto
UUID GeneratorHash GeneratorPassword GeneratorBcrypt GeneratorChecksum CalculatorMD5 Hash GeneratorSHA-256 Hash GeneratorRSA Key Generator
View all Hashing & Crypto tools
Comments