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Free Online HMAC Generator

Generate HMAC signatures using SHA-1, SHA-256, SHA-384, or SHA-512. Client-side and private.

What is HMAC?

HMAC (Hash-based Message Authentication Code) is a specific type of message authentication code that uses a cryptographic hash function combined with a secret key. It provides both data integrity verification and authentication of the message sender.

HMAC is widely used in API authentication (e.g., AWS Signature V4), JWT signing, webhook verification, and secure communication protocols like TLS and IPsec.

Key Features

Multiple Algorithms

Supports SHA-1, SHA-256, SHA-384, and SHA-512 for different security levels.

Web Crypto API

Uses the browser's native cryptographic implementation for maximum security.

Output Formats

Get results in hexadecimal or Base64 encoding to match your use case.

100% Client-Side

Your secret key never leaves your browser. No server requests.

Frequently Asked Questions

What's the difference between HMAC and a regular hash?
A regular hash only provides integrity (detecting changes). HMAC additionally provides authentication - you can verify that the message came from someone who knows the secret key.
Which algorithm should I use?
HMAC-SHA256 is the most common choice and is recommended for most use cases. Use SHA-512 for higher security requirements.
Is my secret key safe?
Yes. All operations run entirely in your browser using the Web Crypto API. Your key is never transmitted anywhere.
Where is HMAC used?
HMAC is used in API authentication (AWS, Stripe), JWT tokens (HS256), webhook verification, OAuth signatures, and more.

Need more crypto tools?

Try our Hash Generator, AES Encryption, or RSA Key Generator tools.

All Tools

About the HMAC Generator

The HMAC Generator is a free online tool that lets you generate HMAC signatures with SHA-256, SHA-512, and more. It runs entirely in your browser with no sign-up required, so you get instant results while your data stays on your device. It is built for developers, designers, and anyone who needs a fast, reliable hmac generator without installing software.

How to use the HMAC Generator

  1. 1Open the HMAC Generator and enter or paste your input.
  2. 2Adjust the available options to match what you need.
  3. 3View the result instantly as you work.
  4. 4Copy or download the output to use in your project.

Frequently asked questions

Is the HMAC Generator free to use?

Yes. The HMAC Generator is completely free with no account, sign-up, or installation required.

Is my data private when I use the HMAC Generator?

This tool runs entirely in your browser. Your data is never uploaded to a server, which makes it safe to use with sensitive input.

Do I need to install anything?

No. The HMAC Generator works in any modern web browser on desktop or mobile, with nothing to download.

Can I use the HMAC Generator on mobile?

Yes. The tool is responsive and works on phones, tablets, and desktops.

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