Service worker lifecycle
- Warm-up strategies, idempotent init, lazy imports, alarms for periodic work.
- Keep long work out of transient events; use queues/backoff.
Resources / Guide
Manifest V3 Guide
Everything you need to plan, build, and migrate MV3—without breaking workflows or performance.
Service Worker
declarativeNetRequest
Messaging
Publishing
TL;DR (Executive summary)
MV3 replaces background pages with service workers, shifts blocking to declarativeNetRequest (DNR), and tightens privacy & permissions. Design around lifecycle limits, quotas, and policy expectations.
Section snippets (examples)
DNR vs webRequest
- Map use-cases to declarative rules; handle limits; log rule hits for debugging.
Permissions & privacy
- Least-privilege host permissions, user triggers, clear consent flows; accurate privacy labels tied to real data paths.
Migration checklist
- Inventory features/permissions → Parity map
- Refactor to SW/DNR
- Add telemetry
- Harden CSP & permissions
- Update listing assets → Submit → Reviewer Q&A
Callouts
Pitfalls: relying on long-lived state in SW; over-broad host permissions.
Good patterns: message-based orchestration; explicit user action gates.
MV2 → MV3: what actually changed
Background pages → service workers, blocking → DNR, stricter privacy, tighter permissions, and new quotas.
Offscreen documents
Use offscreen docs for rendering/DOM operations you can’t do in a worker—create and close explicitly.
Storage & quotas
Prefer IndexedDB for volume; use chrome.storage for settings; respect sync limits.
Messaging patterns
Use one-off messages for simple RPC; ports or BroadcastChannel for streams/long-lived coordination.
Scheduling & background work
Alarms + fetch + queues handle periodic jobs; keep steps idempotent; add backoff.
Testing & QA
Unit + integration + e2e (Playwright). Capture runtime errors; assert CSP and permissions.
Publishing & reviewer Q&A
Accurate permissions, privacy labels, and proactive answers reduce rejections.
Troubleshooting
Cold starts: warm alarms; timeouts: split tasks + queues; CSP: tighten and document sources.