HMAC Generator
Free HMAC generator. Create HMAC signatures with SHA-1, 256, 384 or 512 and any secret. Hex and Base64 output. For webhook signing, API auth.
Runs in your browserUpdated Apr 26, 2026
Input
Output
Hex
Base64
Frequently asked questions
›What is HMAC?
Hash-based Message Authentication Code — a way to verify a message hasn't been tampered with using a shared secret. Common in webhook signing.
›Is HMAC encryption?
No — HMAC is authentication. The message itself is in cleartext; HMAC just lets the receiver verify it came from someone with the same secret.
›Which algorithm should I use?
HMAC-SHA256 is the modern default. HMAC-SHA1 is still common in older systems but should be avoided for new work.
›Is my secret sent to a server?
No — generation runs entirely in your browser via the Web Crypto API.
›Is the generator free?
Yes — fully free, no signup.