Install with Plasmo

Plasmo builds the manifest from your files and package.json. The AnalyticsTrend extension SDK needs nothing Plasmo-specific: start it in the background, and send from pages through it.

Tested with Plasmo 0.90.5 on Node 24. Plasmo's own releases have slowed since 2025; for a new project, WXT is the framework these guides cover most closely.

npm install @analyticstrend/extension

The background

// background.ts
import { initBackground } from "@analyticstrend/extension";

const analytics = initBackground({
  writeKey: process.env.PLASMO_PUBLIC_ANALYTICSTREND_WRITE_KEY,
  uninstallTracking: true,
});

analytics.track("background_started");

At the top level, so it runs on every background start, and not awaited: Chrome will not run a service worker that uses top-level await. Plasmo inlines variables that start with PLASMO_PUBLIC_ at build time, from your .env file or the environment.

From the popup

import { trackFromContentScript } from "@analyticstrend/extension";

trackFromContentScript("popup_opened");

The manifest

Plasmo reads manifest settings from manifest in package.json:

{
  "manifest": {
    "permissions": ["storage"],
    "browser_specific_settings": {
      "gecko": {
        "id": "your-extension@example.com",
        "strict_min_version": "140.0",
        "data_collection_permissions": {
          "required": ["none"],
          "optional": ["technicalAndInteraction", "locationInfo"]
        }
      }
    }
  }
}

Plasmo leaves browser_specific_settings out of the Chrome build by itself, so one package.json serves both browsers.

Build for Firefox

plasmo build --target=firefox-mv3

The build is in build/firefox-mv3-prod, with background scripts in place of Chrome's service worker. The SDK honours the person's data-collection choice itself, as the Firefox guide explains.

The Plasmo example builds for both browsers in CI.