Third-Party Script Monitoring

An ad partner swaps a creative, an analytics vendor ships a new tag, a chat widget auto-updates — and your layout breaks. You don't find out until a customer complains. Frontguard's third-party script plugin inventories the scripts on each page and reports when third-party origins appear or disappear between runs.

How it works

During rendering, the plugin parses each page's DOM snapshot for <script src> origins and classifies them as first-party (same origin as your baseUrl) or third-party. It persists the third-party inventory per route+viewport and diffs the current run against the previous one:

• The first run for a page establishes a baseline (no diff reported).
• Subsequent runs report any added or removed third-party origins.

Enabling it

import { createThirdPartyScriptPlugin } from '@frontguard/cli/plugins';

export default {
  baseUrl: 'https://shop.example.com',
  plugins: [
    createThirdPartyScriptPlugin({
      historyDir: '.frontguard/script-inventory', // default
    }),
  ],
};

In reports

When third-party origins change, a 🧩 Third-party scripts section lists what appeared (➕) and disappeared (➖) per page:

🧩 THIRD-PARTY SCRIPTS
    /            @ 1440px
      + https://ads.network
      - https://old-analytics.io

The same findings are available on RunResult.thirdPartyScripts in the JSON output, and rendered in the HTML and PR reports.