Create and verify HMAC signatures (SHA-256, SHA-384, SHA-512) in your browser. Input message and secret key, get the HMAC signature. All local, no data sent.
Open HMAC Generator → free, no sign-inHMAC — Hash-based Message Authentication Code — is the standard way to verify that a message hasn't been tampered with and comes from someone who knows the secret key. It's used in API authentication, webhook validation, and secure data exchange. The HMAC Generator creates and verifies HMAC-SHA256, SHA-384, and SHA-512 signatures directly in the browser — paste your message, enter your key, get the signature.
Developers validating webhook payloads, building API authentication, implementing HMAC signatures for secure data exchange, or debugging HMAC verification failures by comparing expected vs actual signatures.
No tutorials. No learning curve. Open it and get started.
No server uploads. Supports HMAC-SHA256, SHA-384, and SHA-512 — the three variants used by the majority of real-world HMAC implementations.
Completely free. No trial period. No premium tier for basic functionality. No account required. Use it as often as you need.
One job, done well. HMAC Generator was built to solve a specific problem cleanly. No feature bloat, no ads, no distractions.
What is HMAC used for?
HMAC verifies that a message came from someone with the secret key and hasn't been tampered with. Used in API authentication, webhook security, and JWT signing.
What algorithm should I choose?
HMAC-SHA256 is the most widely used. Use SHA-384 or SHA-512 for higher security requirements.
Is the secret key safe?
It never leaves your browser — all computation is local.
What format is the signature?
Both hex and Base64 output are provided.
Can I verify an existing HMAC?
Yes — the verify mode computes the expected HMAC and compares it to one you provide.
Free. Instant. No sign-in. Open it and get the job done.
Open HMAC Generator on Doathingy.com →