HMAC Generator
Create keyed HMAC-SHA signatures from a message and secret key locally.
Keyed HMAC signatures
An HMAC proves a message was created by someone holding a shared secret, which is how webhooks and API requests are verified. This generator computes HMAC-SHA signatures from a message and key using the browser’s Web Crypto, so you can reproduce or check a signature.
Because it uses SubtleCrypto, the signing is real and standards-based. It is handy for debugging webhook verification and understanding how a provider signs requests — though for genuine production secrets, be mindful of where you paste them.
Signatures, kept private
An HMAC combines your message with a shared secret, which is how a webhook receiver confirms a request is genuine. Both are processed in your browser, so the secret never leaves your device.
Frequently Asked Questions
What does the hmac generator do?
It processes pasted developer text in your browser and writes a usable result to the output panel.
Does this send code or data to a server?
No. The tool runs client-side in your browser and does not upload your input.
What are the limits?
It is designed for everyday snippets, configuration values, and small files rather than huge production datasets.
Is this free?
Yes. It is a free browser utility with no account required.
Practical utilities for everyday web development work.