HMAC Generator
Last updated: 2026 · Free online tool
What is HMAC Generator?
Free online HMAC generator to create keyed message authentication codes with HMAC-SHA256 or HMAC-SHA512. Enter a message and secret key to compute a signature and verify webhooks and APIs.
How to Use
- 1 Select Mode — Choose generation or verification mode.
- 2 Enter Input — Enter the message and secret key.
- 3 View Result — Copy the generated HMAC or check the verification result (match/mismatch).
Related Tools
SHA-256 Hash Generator Free online SHA-256 hash generator that computes secure SHA-256 digests from text or uploaded files using the Web Crypto API, supports HMAC-SHA256 with a secret key, and lets you verify hashes by comparison.
MD5 Hash Generator Free online tool to generate MD5 hashes from text or files with a pure JavaScript implementation based on RFC 1321, for integrity checks and data verification.
Hash Compare Free online hash compare tool to verify file integrity and checksums. Paste two hash values or compute MD5, SHA-1 and SHA-256 of a file and instantly see whether they match.
Frequently Asked Questions
HMAC (Hash-based Message Authentication Code) is a method that generates message authentication codes using a secret key and hash function.
HMAC-SHA256 and HMAC-SHA512 are supported, using the Web Crypto API.
Presets for commonly used API signatures like Stripe, GitHub, and Slack webhooks are provided.
Yes, verification mode uses constant-time comparison to prevent timing attacks.
No. All calculations are performed in the browser via Web Crypto API.