GTM Phantom

👻 Load YOUR Google Tag Manager container on any website - a client's staging site, a third-party-hosted checkout, a page whose container is broken or missing. Paste the snippet once; GTM Phantom injects it on every page load of the domains you choose. ⚡ WHAT IT DOES 🎯 Inject on any site: your snippet runs in the page (MAIN world) at document_start - the same effect as pasting it in the site's <head>. 📋 Multiple rules: one per site, each with its own snippet. Pause, edit, delete independently. 🌐 Subdomain coverage per rule (*.example.com). 🔄 REPLACE MODE: block the container(s) the site already loads at the network level, so your container runs INSTEAD of the site's one - no double tags, no double hits. Only the GTM id found in your snippet stays allowed, and blocking is active only while your rule is actually injecting. 🟣 Toolbar badge: ON on every covered tab. ♻️ Auto-reload of open tabs when you save a rule. 👥 BUILT FOR Web analysts, tag-management consultants, agencies and developers who need their own container running on a page they don't control yet. 🛡️ HOW IT WORKS (AND WHY IT'S POLICY-COMPLIANT) Phantom never ships or builds a GTM loader itself. You paste the container snippet exactly as Tag Manager hands it out, and Phantom registers it through chrome.userScripts - the Chrome API made precisely for running user-provided scripts. The code that runs is yours, not the extension's. That's also why Chrome asks you to enable "Allow user scripts" once on the extension's details page (Chrome 138+). 🔒 PRIVACY No analytics, no remote calls, no accounts. Rules and snippets live in chrome.storage.local and never leave your browser. Host access is granted by you, per domain, when you save a rule. ✅ VERIFYING On a covered page, DevTools → Object.keys(google_tag_manager) shows your GTM-XXXX. Tag Assistant and GTM preview mode work normally.