HMAC generator
Generate HMAC digests using a secret key and various hash algorithms. Verify existing HMACs for webhook and API signature checking.
- Free, no sign-up
- No data stored
- Reviewed 2026-01-15
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About the HMAC Generator
Generate a Hash-based Message Authentication Code (HMAC) from an input message and a secret key. Choose the hash algorithm (SHA-256, SHA-384, SHA-512, SHA-1, MD5) and output encoding (hex or Base64). Paste an expected HMAC to verify a match.
How to use the HMAC Generator
- Enter the message.
- Enter the secret key.
- Select the algorithm.
- Choose output encoding.
- Optionally paste an HMAC to verify.
Frequently asked questions
What is HMAC used for?
Verifying message integrity and authenticity. Common uses: webhook signatures (Stripe, GitHub), API request signing (AWS Signature v4), JWT signatures.
Is HMAC-SHA256 secure?
Yes. HMAC-SHA256 is the industry standard for most applications. It is resistant to length-extension attacks that affect plain SHA-256.
What if my key contains special characters?
Enter the key as-is. If your API provides a Base64-encoded key, decode it first before using here.