Developer Tools
HMAC Generator
Paste the message, add a secret, choose an algorithm, and generate an HMAC signature in seconds. This page is useful for API signing, webhook verification checks, auth debugging, and quick developer workflows.
Generate HMAC Signatures Online
Generate HMAC signatures online for API signing, webhook debugging, authentication flows, and request verification.
Why Use This HMAC Generator
- Inspect and transform developer-focused text quickly
- Copy results for debugging, documentation, and integrations
- Use sample input for quick testing
- Download the output as a file
Related Developer Tools
- Developer Tools Hub
- Markdown Editor & Preview
- Lorem Ipsum Generator
- UUID / ULID Generator
- Hash Generator
- Slug Generator
- Word & Character Counter
- Case Converter
- Text Sorter & Deduplicator
- JSON Diff & Merge
- JSON Schema Generator
- BCrypt Hash Generator
- BCrypt Hash Verifier
- Diff Checker
- JWT Decoder
- URL Parser
- Query String Parser
- Query String Builder
- JSON Minifier
Common Situations Where This Helps
- You need to reproduce an API request signature locally.
- A webhook integration asks you to compare an HMAC signature.
- You want to test how a different secret changes the output.
- You need both hex and Base64 outputs for different systems.
Which Tool Should You Choose?
HMAC-SHA256: Choose HMAC-SHA256 for the most common modern API signing and webhook verification workflows.
HMAC-SHA1: Choose HMAC-SHA1 only when an older integration explicitly requires it.
HMAC-SHA384 / HMAC-SHA512: Choose these when a system requires a longer digest or stronger keyed hash output.
Common Problems and Fixes
My generated signature does not match what the API expects.
Check that the secret, exact message body, line breaks, encoding, and HMAC algorithm all match the upstream system.
Another system expects Base64 instead of hex.
Use the Base64 output from this page instead of converting the hex digest manually.
I am not sure which HMAC algorithm to choose.
Use the exact algorithm named by the API or webhook provider. If the docs say HMAC-SHA256, choose SHA-256 here.
Related Guides
Frequently Asked Questions
How do I generate an HMAC signature?
Paste the message, enter the secret key, choose the HMAC algorithm, and run the tool to generate hex and Base64 outputs.
What is the difference between a hash and an HMAC?
A hash works on the input alone, while an HMAC combines the input with a secret key to produce a keyed signature.
Is this HMAC generator free?
Yes. It is free to use on the site.