What makes HMAC more secure than a plain hash?

A plain hash can be forged — anyone can compute the hash of any message. An HMAC requires knowing the secret key to produce a valid authentication code. Without the key, you cannot compute or verify the HMAC.

Which algorithm should I use for HMAC?

Use HMAC-SHA256 as the default — it is the industry standard used by AWS, Stripe, GitHub webhooks, and most modern APIs. HMAC-SHA512 provides stronger security at a small performance cost. Avoid HMAC-MD5 and HMAC-SHA1 for new systems.

How do I verify an incoming webhook signature with HMAC?

Compute the HMAC of the raw request body using your shared secret. Compare it byte-by-byte (using a timing-safe comparison) against the signature provided in the webhook header. If they match, the payload is authentic.

Home ToolsHMAC Generator

HMAC Generator

Name: HMAC Generator
Rating: 4.8 (120 reviews)
Author: DailyDevTools

Generate keyed-hash message authentication codes

Message

Secret

Algorithm

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What is HMAC Generator?

HMAC (Hash-based Message Authentication Code) provides message integrity and authenticity by combining a cryptographic hash function with a secret key. HMACs are used to sign API requests (AWS Signature, Stripe webhooks), verify webhook payloads, and authenticate JWT tokens. DailyDevTools' HMAC Generator computes HMAC-SHA256, HMAC-SHA512, HMAC-SHA1, and HMAC-MD5 using the Web Crypto API.

How to use HMAC Generator

1Enter the message you want to authenticate in the Message field
2Enter your secret key in the Key field — this is the shared secret between sender and receiver
3Select the hash algorithm: HMAC-SHA256 (recommended), SHA512, SHA1, or MD5
4The HMAC signature is generated instantly and displayed in both hex and Base64 formats

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