Security Utility
HMAC Signature Generator
Generate cryptographic Hash-based Message Authentication Codes for API requests, webhooks, and signatures.
100% In-Browser Client-Side — Zero Server Uploads
Calculated using native Web Crypto API. Zero server communication.
HMAC SHA-256 Signature (HEX)
(Enter message and secret key above)
Verifying Webhooks with HMAC Signatures
When receiving webhooks from payment gateways or external third-party services, computing an HMAC hash of the raw incoming payload with your webhook secret proves that the notification originated from the authentic provider and was not tampered with in transit.
Frequently Asked Questions
Helpful answers to common image compression questions.
HMAC (Hash-based Message Authentication Code) combines a cryptographic hash function with a secret shared key to verify both data integrity and sender authenticity.
Related Security & Web Utilities
JWT Decoder & Expiry Checker
Decode JWT tokens and check expiration claims.
Open tool
Password Strength & Entropy
Calculate Shannon entropy and crack times.
Open tool
Content Security Policy (CSP) Builder
Build Content Security Policy headers & tags.
Open tool
Image Compressor
Compress images to target file size in KB/MB.
Open tool