Invalid key format for selected type.
Result will appear here...
CALCULATED INSTANTLY
Securely generate HMAC signatures using the Web Crypto API. Private, fast, and entirely client-side.
This HMAC generator uses the browser's native Web Crypto API. Your secret key and message never leave your device. We do not store, track, or transmit any data entered into this tool.
Instantly toggle between UTF-8, Hex, and Base64 key formats. Generate standard HMAC-SHA256 signatures for API authentication, webhooks, and secure handshakes.
HMAC (Hash-based Message Authentication Code) is a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. It may be used to simultaneously verify both the data integrity and the authenticity of a message.
SHA-256 is a 256-bit (32-byte) hashing algorithm which is part of the SHA-2 family. When combined, HMAC-SHA256 provides a robust mechanism for verifying that a message has not been altered and that it originated from a trusted source who possesses the secret key.