HMAC SHA-256 Generator Online (Free, Private)
Generate HMAC-SHA256 signatures in the Hash/HMAC workbench. SHA-384 and SHA-512 included — secrets never uploaded.
HMAC (Hash-based Message Authentication Code) combines a secret key with a message to produce a signature. APIs like Stripe, Shopify, and GitHub webhooks use HMAC-SHA256 so receivers can verify requests were not tampered with.
HMAC tab in the workbench
- Enter secret key and message — output updates live
- Switch between HMAC-SHA256, SHA-384, and SHA-512
- Hash tab available on the same page for plain digests
- Link to JWT workbench for token verification
Never upload your secret key
Server-side HMAC tools receive your API secret on their servers. Utiliio computes HMAC entirely in your browser using the Web Crypto API.
Open Hash/HMAC workbench →Compare Utiliio vs online hash tools →