Community WXT Browser Extensions Best Practices

Comprehensive performance optimization guide for WXT browser extension development. Contains 49 rules across 8 categories, prioritized by impact to guide automated refactoring and code generation. Updated for WXT v0.20+.

When to Apply

Reference these guidelines when:

• Writing new WXT browser extension code
• Implementing service worker background scripts
• Injecting content scripts into web pages
• Setting up messaging between extension contexts
• Configuring manifest permissions and resources

Rule Categories by Priority

svc-

inject-

msg-

store-

bundle-

manifest-

ui-

ts-

Quick Reference

1. Service Worker Lifecycle (CRITICAL)

• svc-register-listeners-synchronously

  - Register listeners synchronously to prevent missed events

• svc-avoid-global-state

  - Use storage instead of in-memory state

• svc-keep-alive-patterns

  - Keep service worker alive for long operations

• svc-handle-install-update

  - Handle install and update lifecycle events

• svc-offscreen-documents

  - Use offscreen documents for DOM operations

• svc-declarative-net-request

  - Use declarative rules for network blocking

2. Content Script Injection (CRITICAL)

• inject-use-main-function

  - Place runtime code inside main() function

• inject-choose-correct-world

  - Select ISOLATED or MAIN world appropriately

• inject-run-at-timing

  - Configure appropriate runAt timing

• inject-use-ctx-invalidated

  - Handle context invalidation on update

• inject-dynamic-registration

  - Use runtime registration for conditional injection

• inject-all-frames

  - Configure allFrames for iframe handling

• inject-spa-navigation

  - Handle SPA navigation with wxt:locationchange

3. Messaging Architecture (HIGH)

• msg-type-safe-messaging

  - Use @webext-core/messaging for type-safe protocols

• msg-return-true-for-async

  - Return true for async message handlers (raw API)

• msg-use-tabs-sendmessage

  - Use tabs.sendMessage for content scripts

• msg-use-ports-for-streams

  - Use ports for streaming communication

• msg-handle-no-receiver

  - Handle missing message receivers

• msg-avoid-circular-messages

  - Prevent circular message loops

4. Storage Patterns (HIGH)

• store-use-define-item

  - Use storage.defineItem for type-safe access

• store-choose-storage-area

  - Select appropriate storage area

• store-batch-operations

  - Group related data into single defineItem

• store-watch-for-changes

  - Use watch() for reactive updates

• store-handle-quota-errors

  - Handle storage quota errors

• store-versioned-migrations

  - Use versioning for schema migrations

5. Bundle Optimization (MEDIUM-HIGH)

• bundle-split-entrypoints

  - Split code by entrypoint

• bundle-analyze-size

  - Analyze and monitor bundle size

• bundle-tree-shake-icons

  - Use direct imports for icon libraries

• bundle-externalize-wasm

  - Load WASM dynamically

• bundle-minify-content-scripts

  - Minimize content script size

6. Manifest Configuration (MEDIUM)

• manifest-minimal-permissions

  - Request minimal permissions

• manifest-use-optional-permissions

  - Use optional permissions progressively

• manifest-web-accessible-resources

  - Scope web accessible resources

• manifest-content-security-policy

  - Configure CSP correctly

• manifest-cross-browser-compatibility

  - Support multiple browsers

7. UI Performance (MEDIUM)

• ui-use-shadow-dom

  - Use Shadow DOM for injected UI

• ui-defer-rendering

  - Defer popup rendering until needed

• ui-cleanup-on-unmount

  - Clean up UI on unmount

• ui-sidepanel-persistence

  - Preserve sidepanel state

• ui-position-fixed-iframe

  - Use iframe for complex UI

• ui-avoid-layout-thrashing

  - Batch DOM reads and writes

8. TypeScript Patterns (LOW-MEDIUM)

• ts-use-imports-module

  - Use #imports virtual module and auto-imports

• ts-use-browser-not-chrome

  - Use browser namespace over chrome

• ts-type-entrypoint-options

  - Type entrypoint options explicitly

• ts-augment-browser-types

  - Augment types for missing APIs

• ts-strict-null-checks

  - Enable strict null checks

• ts-import-meta-env

  - Use import.meta for build info

• ts-avoid-any

  - Avoid any type in handlers

• ts-path-aliases

  - Use path aliases for imports

How to Use

Read individual reference files for detailed explanations and code examples:

• Section definitions - Category structure and impact levels
• Rule template - Template for adding new rules

Reference Files