Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
HMAC Generator
Generate Hash-based Message Authentication Codes with your secret key.
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Verify HMAC
Paste an HMAC signature to verify against the current message and secret key.
What is HMAC?
HMAC (Hash-based Message Authentication Code) is a mechanism for calculating a message authentication code using a hash function combined with a secret key. It provides both data integrity and authenticity.
Unlike regular hashing (which anyone can compute), only parties who know the secret key can generate or verify an HMAC. This makes it ideal for API authentication, webhook verification, and secure message exchange.
All HMAC generation is performed 100% client-side using the Web Crypto API. Your secret key never leaves your browser.
How to Use
- Enter your message — Type or paste the message you want to sign in the message field.
- Provide a secret key — Enter your secret key or click the random key button to generate one.
- Choose algorithm & encoding — Select SHA256, SHA1, SHA384, or SHA512 and choose hex, base64, or base64url output.
- Generate — Click Generate HMAC to create the signature.
- Verify — Paste an existing HMAC in the verify section to check if it matches your message and secret key.
Frequently Asked Questions
What is HMAC Generator?
1. This tool provides a free, online solution that works directly in your browser without requiring any installation or registration.
How do I use HMAC Generator?
Simply enter your input in the provided text area or form, configure any available options, and click the action button to get your result. The tool processes everything instantly and displays the output in the results section.
Is my data sent to a server or stored?
No. All processing is performed locally in your browser using JavaScript. Your data never leaves your device, is not stored, logged, or shared with any third party. This makes the tool completely safe for handling sensitive information.
How are security headers evaluated?
Each security header is checked for presence and correctness based on current security best practices. The overall grade reflects how many critical headers are present and properly configured. Missing or misconfigured headers reduce the grade.
Is this tool free to use?
Yes. This tool is completely free to use with no limitations, registration, or API key required. There are no usage caps, and you can use it as often as you need.
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Last updated: 17 Aug 2026
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