Extension Migration (MV2 → MV3)

Official migration guide: https://developer.chrome.com/docs/extensions/develop/migrate

Consider framework adoption: When migrating MV2→MV3, consider adopting WXT or Plasmo for built-in MV3 support, auto-manifest generation, and modern tooling.

Workflow Overview

1. Audit existing MV2 extension (APIs, permissions, background scripts)
2. Update manifest_version to 3
3. Convert background page → service worker
4. Replace deprecated APIs (see Quick Reference below)
5. Update permissions, CSP, web_accessible_resources format
6. Migrate webRequest → declarativeNetRequest (if blocking)
7. Bundle any remote code locally
8. Test all functionality across Chrome versions
9. Submit to Chrome Web Store

Key Breaking Changes