Feature Flag Scanner is a free Chrome extension designed for developers and QA professionals to inspect visible feature flags on websites. This tool scans the current web page for feature flags and traces from feature flag SDKs, allowing users to analyze various browser-visible sources such as page markup, inline scripts, and cookies. The extension provides detailed results that include detected flag names, their current values, sources, and evidence, as well as patterns and confidence levels for each flag.

This extension facilitates common tasks such as QA rollout verification, frontend branch testing, and debugging experiments. Users can also save local overrides for flags that need testing, with the ability to reload the page and reapply overrides for specific site origins. However, it is important to note that the tool cannot inspect server-side flags or read HttpOnly cookies.