Environment Variables

Replaces your new tab page with a page showing the extension's environment values.

Runs on Chrome, Edge, Firefox · Manifest V3 · Surfaces: new tab, background service worker · Styling: CSS · Level: beginner

Create this project

npx extension@latest create my-new-env --template new-env
cd my-new-env
npm install
npm run dev

What it is for

  • Inject build-time configuration without leaking secrets
  • Switch behavior per browser, mode, or deployment target
  • Reference for safe env-var usage across JS, JSON, and HTML

First steps

  • Copy .env.example to .env and edit the values
  • Run npm run dev to launch the extension
  • Open a new tab and the page reads injected EXTENSION_PUBLIC_* values

Permissions it asks for

This template requests no permissions.

Source on GitHubDocumentation

extension.devDocumentation for extension.dev