This tutorial walks through a minimal Manifest V3 extension you can hand to an AI builder or extend yourself. Payhook tutorials assume you already have this skeleton before wiring payments.

What you will build

• manifest.json with MV3 fields
• A service worker (background.js) for long-lived logic
• A popup (popup.html + popup.js) for user-facing controls

manifest.json

{
  "manifest_version": 3,
  "name": "My Extension",
  "version": "0.1.0",
  "description": "Starter MV3 extension",
  "action": {
    "default_popup": "popup.html",
    "default_title": "My Extension"
  },
  "background": {
    "service_worker": "background.js"
  },
  "permissions": ["storage"]
}

Load unpacked in chrome://extensions with Developer mode enabled.

Popup vs background

Surface	Use for
Popup	Buttons, upgrade CTA, quick settings
Service worker	Entitlement checks, messaging, alarms

Next steps

1. Firefox extension Manifest V3 starter - gecko ID and about:debugging
2. Safari Web Extension Manifest V3 starter - web layer + Xcode wrapper
3. Stripe Connect for extension builders - products and checkout concepts
4. Monetize a browser extension without a payment backend - hosted checkout without a custom payment backend

Related: Payhook docs, acme-extension sample.