Last Updated: February 19, 2026
A/B Test Detector ("we", "our", or "the extension") is an open-source browser extension designed to help developers and marketers detect A/B testing experiments on websites.
We do not collect, store, or transmit your personal data.
The extension operates entirely locally on your device.
The extension scans the websites you visit (<all_urls>) to identify active A/B testing scripts (such as Optimizely, VWO, Convert, etc.) and extract experiment data from the global window object.
- This data is displayed to you in the extension popup or DevTools panel.
- This data is never sent to our servers or third parties.
- The data is temporarily stored in your browser's local storage (
chrome.storage.local) for the duration of your session and is cleared when you close the tab.
The extension monitors network requests (webRequest permission) solely to detect the presence of A/B testing tools (e.g., detecting a request to cdn.optimizely.com).
- We do not read the content of your requests, headers, or cookies.
- We do not track your browsing history.
- This detection happens locally on your device.
The extension does not use any third-party analytics services (like Google Analytics) to track your usage of the extension itself.
If you have questions about this policy, please contact us via email at team@brillmark.com.