GTM99 · Privacy Policy

GTM99 is a Chrome DevTools extension for diagnosing a web page's analytics and tag-management setup.

What GTM99 accesses

While its DevTools panel is open, GTM99 observes the outgoing analytics and advertising network requests of the tab you are inspecting (and, for some pixels, their request bodies) in order to display them to you.
It reads the page's tag-management state (for example window.dataLayer and window.google_tag_manager) via the standard Chrome DevTools API.
It stores two small preferences: your chosen color theme and a first-run (“intro seen”) flag.

It does not transmit, sell, or share any data. All captured request data stays in your browser's memory, grouped by the site it came from, and is discarded when the tab is closed or when you clear it from the panel.
It does not use analytics, tracking, or any external servers.
It does not load any remote code or remote resources. All code and fonts are bundled in the extension.
It does not modify the pages you visit or change their tracking behavior.

Captured request data is held in memory only and is never written to disk.
Preferences are stored locally via chrome.storage and contain no personal information.

GTM99 is built by Carlos Pinto. Questions or concerns:

Last updated: 11 July 2026.