HMAC Generator
Generate HMAC-SHA256, SHA-512, SHA-1 or MD5 signatures in hex and Base64. Free and private: runs in your browser.
Enter the message, a line with ---, then the secret key. Handy for testing webhook signatures from Stripe, GitHub or Razorpay.
Hashing runs locally in your browser. Your input never leaves this page.
Use cases
- Verify a download or file checksum.
- Create test fixtures for authentication code.
- Debug a hash mismatch between two systems.
Frequently asked questions
Why does my webhook signature not match?
Sign the raw request body exactly as received. Re-serialising JSON changes spacing and key order, which changes the HMAC.
Is the HMAC Generator free?
Yes. It is free with no sign-up, and it runs entirely in your browser, so your input is never uploaded or stored.
Is hashing the same as encryption?
No. A hash is one-way: you cannot get the input back. Encryption is reversible with a key. Use slow password hashes (bcrypt, Argon2, PBKDF2) for passwords and fast hashes (SHA-256) for integrity checks.
Related tools
Checking one snippet is a start. Scan your whole repository for free with CodeInspector.