Capacitor Expert

Comprehensive reference for building cross-platform apps with Capacitor. Covers architecture, CLI, plugins, framework integration, best practices, and Capawesome Cloud.

Core Concepts

Capacitor is a cross-platform native runtime for building web apps that run natively on iOS, Android, and the web. The web app runs in a native WebView, and Capacitor provides a bridge to native APIs via plugins.

Architecture

A Capacitor app has three layers:

Web layer -- HTML/CSS/JS app running inside a native WebView (WKWebView on iOS, Android System WebView on Android).
Native bridge -- Serializes JS plugin calls, routes them to native code, and returns results as Promises.
Native layer -- Swift/ObjC (iOS) and Kotlin/Java (Android) code implementing native functionality.

Data passed across the bridge must be JSON-serializable. Pass files as paths, not base64.

Project Structure

my-app/
  android/                  # Native Android project (committed to VCS)
  ios/                      # Native iOS project (committed to VCS)
    App/
      App/                  # iOS app source files
      App.xcodeproj/
  src/                      # Web app source code
  dist/ or www/ or build/   # Built web assets
  capacitor.config.ts       # Capacitor configuration
  package.json

The

android/

and

ios/

directories are full native projects -- they are committed to version control and can be modified directly.

Capacitor Config

capacitor.config.ts

(preferred) or

capacitor.config.json

controls app behavior:

typescript

import type { CapacitorConfig } from '@capacitor/cli';

const config: CapacitorConfig = {
  appId: 'com.example.app',
  appName: 'My App',
  webDir: 'dist',
  server: {
    // androidScheme: 'https', // default in Cap 6+
  },
};

export default config;

For details, see App Configuration.

Creating a New App

Quick Start

bash

# 1. Create a web app (React example with Vite)
npm create vite@latest my-app -- --template react-ts
cd my-app && npm install

# 2. Install Capacitor
npm install @capacitor/core
npm install -D @capacitor/cli

# 3. Initialize Capacitor
npx cap init "My App" com.example.myapp --web-dir dist

# 4. Build web assets
npm run build

# 5. Add platforms
npm install @capacitor/android @capacitor/ios
npx cap add android
npx cap add ios

# 6. Sync and run
npx cap sync
npx cap run android
npx cap run ios

Web asset directories by framework:

Angular:
```
dist/<project-name>/browser
```
(Angular 17+ with application builder)
React (Vite):
```
dist
```
Vue (Vite):
```
dist
```
Vanilla:
```
www
```

For the full guided creation flow, see capacitor-app-creation.

Capacitor CLI

All commands:

npx cap <command>

. Most important commands:

Command	Purpose
`npx cap init <name> <id>`	Initialize Capacitor in a project
`npx cap add <platform>`	Add Android or iOS platform
`npx cap sync`	Copy web assets + update native dependencies (run after every plugin install, config change, or web build)
`npx cap copy`	Copy web assets only (faster, no native dependency update)
`npx cap run <platform>`	Build, sync, and deploy to device/emulator
`npx cap run <platform> -l --external`	Run with live reload
`npx cap open <platform>`	Open native project in IDE
`npx cap build <platform>`	Build native project
`npx cap doctor`	Diagnose configuration issues
`npx cap ls`	List installed plugins
`npx cap migrate`	Automated upgrade to newer Capacitor version

For the full CLI reference, see CLI Reference.

Framework Integration

Capacitor works with any web framework. Framework-specific patterns:

Angular

Wrap Capacitor plugins in Angular services for DI and testability.
Plugin event listeners run outside NgZone -- always wrap callbacks in
```
NgZone.run()
```
.
Register listeners in
```
ngOnInit
```
, remove in
```
ngOnDestroy
```
.

For details, see capacitor-angular.

React

Create custom hooks (
```
useCamera
```
,
```
useNetwork
```
) that wrap Capacitor plugins.
Use
```
useEffect
```
for listener registration with cleanup to prevent memory leaks.
React 18 strict mode double-mounts -- ensure cleanup functions work correctly.

For details, see capacitor-react.

Vue

Create composables (
```
useCamera
```
,
```
useNetwork
```
) using Vue 3 Composition API.
Register listeners in
```
onMounted
```
, remove in
```
onUnmounted
```
.
Vue reactivity picks up
```
ref
```
changes automatically (no NgZone equivalent needed).

For details, see capacitor-vue.

Plugins

Plugins are Capacitor's extension mechanism. Each plugin exposes a JS API backed by native implementations.

Plugin Sources

Official (
```
@capacitor/*
```
) -- Camera, Filesystem, Geolocation, Preferences, etc.
Capawesome (
```
@capawesome/*
```
,
```
@capawesome-team/*
```
) -- SQLite, NFC, Biometrics, Live Update, etc.
Community (
```
@capacitor-community/*
```
) -- AdMob, BLE, SQLite, Stripe, etc.
Firebase (
```
@capacitor-firebase/*
```
) -- Analytics, Auth, Messaging, Firestore, etc.
MLKit (
```
@capacitor-mlkit/*
```
) -- Barcode scanning, face detection, translation.
RevenueCat (
```
@revenuecat/purchases-capacitor
```
) -- In-app purchases.

Installing a Plugin

bash

npm install @capacitor/camera
npx cap sync

After installation, apply any required platform configuration (permissions in

AndroidManifest.xml

Info.plist

entries, etc.) as documented by the plugin.

Using a Plugin

typescript

import { Camera, CameraResultType } from '@capacitor/camera';

const photo = await Camera.getPhoto({
  quality: 90,
  resultType: CameraResultType.Uri,
});

For the full plugin index (160+ plugins) and setup guides, see capacitor-plugins.

Plugin Development

Create custom Capacitor plugins with native iOS (Swift) and Android (Java/Kotlin) implementations:

Scaffold with
```
npm init @capacitor/plugin@latest
```
.
Define the TypeScript API in
```
src/definitions.ts
```
.
Implement the web layer in
```
src/web.ts
```
.
Implement iOS plugin in
```
ios/Sources/
```
.
Implement Android plugin in
```
android/src/main/java/
```
.
Verify with
```
npm run verify
```
.

Key rules:

The

registerPlugin()

name in

src/index.ts

must match

jsName

on iOS and

@CapacitorPlugin(name = "...")

on Android.

iOS methods need
```
@objc
```
and must be listed in
```
pluginMethods
```
(CAPBridgedPlugin).
Android methods need
```
@PluginMethod()
```
annotation and must be
```
public
```
.

For full details, see capacitor-plugin-development.

Cross-Platform Best Practices

Platform Detection

typescript

import { Capacitor } from '@capacitor/core';

const platform = Capacitor.getPlatform(); // 'android' | 'ios' | 'web'
if (Capacitor.isNativePlatform()) { /* native-only code */ }
if (Capacitor.isPluginAvailable('Camera')) { /* plugin available */ }

Permissions

Follow the check-then-request pattern:

typescript

const status = await Camera.checkPermissions();
if (status.camera !== 'granted') {
  const requested = await Camera.requestPermissions();
  if (requested.camera === 'denied') {
    // Guide user to app settings -- cannot re-request on iOS
    return;
  }
}
const photo = await Camera.getPhoto({ ... });

Performance

Minimize bridge calls -- batch operations instead of many individual calls.
Use file paths over base64 for binary data.
Lazy-load plugins with dynamic imports for code splitting.

Error Handling

Always wrap plugin calls in try-catch:

typescript

try {
  const photo = await Camera.getPhoto({ resultType: CameraResultType.Uri });
} catch (error) {
  if (error.message === 'User cancelled photos app') {
    // Not an error
  } else {
    console.error('Camera error:', error);
  }
}

For full details, see Cross-Platform Best Practices.

Deep Links

Deep links open specific content in the app from external URLs.

iOS: Universal Links via

apple-app-site-association

hosted at

https://<domain>/.well-known/

Android: App Links via

assetlinks.json

hosted at

https://<domain>/.well-known/

Listener Setup

typescript

import { App } from '@capacitor/app';

App.addListener('appUrlOpen', (event) => {
  const path = new URL(event.url).pathname;
  // Route to the appropriate page
});

Platform Configuration

iOS: Add

applinks:<domain>

to Associated Domains capability in

ios/App/App/App.entitlements

Android: Add

<intent-filter android:autoVerify="true">

android/app/src/main/AndroidManifest.xml

For full setup, see Deep Links.

Storage

Requirement	Solution
App settings, preferences	`@capacitor/preferences` (native key-value, persists reliably)
Sensitive data (tokens, credentials)	`@capawesome-team/capacitor-secure-preferences` (Keychain/Keystore)
Relational data, offline-first	SQLite ( `@capawesome-team/capacitor-sqlite` or `@capacitor-community/sqlite` )
Files, images, documents	`@capacitor/filesystem`

Do NOT use

localStorage

IndexedDB

, or cookies for persistent data -- the OS can evict them (especially on iOS).

For details, see Storage.

Security

Never embed secrets (API keys with write access, OAuth secrets, DB credentials) in client code -- move to a server API.

Use secure storage (

@capawesome-team/capacitor-secure-preferences

) for tokens and credentials, not

localStorage

@capacitor/preferences

HTTPS only -- never allow cleartext HTTP in production.
Content Security Policy -- add a
```
<meta>
```
CSP tag in
```
index.html
```
.

Disable WebView debugging in production: set

webContentsDebuggingEnabled: false

capacitor.config.ts

Prefer Universal/App Links over custom URL schemes (verified via HTTPS).
iOS Privacy Manifest (
```
PrivacyInfo.xcprivacy
```
) -- required for iOS 17+ when using privacy-sensitive APIs.

For details, see Security.

Testing

Unit Testing

Mock Capacitor plugins in Jest/Vitest since tests run in Node.js, not a WebView:

typescript

vi.mock('@capacitor/camera', () => ({
  Camera: {
    getPhoto: vi.fn().mockResolvedValue({
      webPath: 'https://example.com/photo.jpg',
    }),
  },
}));

E2E Testing

Web E2E: Cypress or Playwright (tests web layer, plugins must be mocked).
Native E2E: Appium (cross-platform) or Detox (iOS-focused).

Debugging

Android: Enable

webContentsDebuggingEnabled: true

, open

chrome://inspect

in Chrome.

iOS: Enable
```
webContentsDebuggingEnabled: true
```
, use Safari > Develop menu > select device.

For details, see Testing.

Troubleshooting

Android

npx cap sync
fails: Verify

@capacitor/core

and

@capacitor/cli

versions match. Run

cd android && ./gradlew clean

Build fails after config changes: Clean with
```
cd android && ./gradlew clean
```
, then rebuild.
Plugin not found at runtime: Run
```
npx cap sync
```
after plugin installation. Verify Gradle sync completed.
SDK errors: Verify
```
ANDROID_HOME
```
is set. Install missing SDK versions via Android Studio SDK Manager.
White square notification icon: Push notification icons must be white pixels on transparent background.

iOS

Build fails with "no such module": Run

npx cap sync ios

. For CocoaPods:

cd ios/App && pod install --repo-update

Build fails after config changes: Clean build folder (Xcode Product > Clean Build Folder) or delete
```
ios/App/Pods
```
and re-run
```
pod install
```
.
Simulator cannot receive push notifications: Use a physical device for push notification testing.
Permission denied permanently: Cannot re-request on iOS. Guide user to Settings > App > Permissions.
WebView not loading: Verify
```
webDir
```
in
```
capacitor.config.ts
```
matches the actual build output directory.

General

Live reload not connecting: Ensure device and dev machine are on the same network. Use
```
--external
```
flag.
Plugin not found: Run
```
npx cap sync
```
. Verify plugin is in
```
package.json
```
dependencies.

Capacitor is not defined
: Install

@capacitor/core

(

npm install @capacitor/core

For full troubleshooting, see Android Troubleshooting and iOS Troubleshooting.

Upgrading

Capacitor supports upgrades across major versions (4 through 8). Apply each major version jump sequentially -- do not skip intermediate versions.

Current to Target	Node.js	Xcode	Android Studio
to 5	16+	14.1+	Flamingo 2022.2.1+
to 6	18+	15.0+	Hedgehog 2023.1.1+
to 7	20+	16.0+	Ladybug 2024.2.1+
to 8	22+	26.0+	Otter 2025.2.1+

Quick automated upgrade:

bash

npx cap migrate
npx cap sync

npx cap migrate

fails partially, apply manual steps from the upgrade guides.

For app upgrades, see capacitor-app-upgrades. For plugin upgrades, see capacitor-plugin-upgrades.

Capawesome Cloud

Capawesome Cloud provides cloud infrastructure for Capacitor apps: native builds, live updates, and automated app store publishing.

Website: capawesome.io | Cloud Services: cloud.capawesome.io

Getting Started

bash

# Install and authenticate
npx @capawesome/cli login

# Create an app
npx @capawesome/cli apps:create

Live Updates

Deploy over-the-air (OTA) web updates to Capacitor apps without going through the app stores. Users receive updates immediately on next app launch.

Setup:

bash

# Install the live update plugin
npm install @capawesome/capacitor-live-update
npx cap sync

Configure in

capacitor.config.ts

typescript

const config: CapacitorConfig = {
  plugins: {
    LiveUpdate: {
      appId: '<APP_ID>',
      autoUpdate: true,
    },
  },
};

Deploy an update:

bash

npm run build
npx @capawesome/cli apps:liveupdates:upload --app-id <APP_ID>

Native Builds

Build iOS and Android apps in the cloud without local build environments. Supports signing certificates, environments, and build configuration.

bash

# Trigger a build
npx @capawesome/cli apps:builds:create --app-id <APP_ID> --platform android

# Download the artifact
npx @capawesome/cli apps:builds:download --app-id <APP_ID> --build-id <BUILD_ID>

App Store Publishing

Automate submissions to Apple App Store (TestFlight) and Google Play Store.

bash

# Create a deployment destination
npx @capawesome/cli apps:destinations:create --app-id <APP_ID>

# Deploy a build
npx @capawesome/cli apps:deployments:create --app-id <APP_ID> --build-id <BUILD_ID>

CI/CD Integration

Use token-based auth for CI/CD pipelines:

bash

npx @capawesome/cli login --token <TOKEN>
npx @capawesome/cli apps:builds:create --app-id <APP_ID> --platform ios --detached

For full Capawesome Cloud setup, see capawesome-cloud. For the Capawesome CLI reference, see capawesome-cli.

Push Notifications

Set up push notifications using Firebase Cloud Messaging (FCM) via

@capacitor-firebase/messaging

bash

npm install @capacitor-firebase/messaging firebase
npx cap sync

Requires Firebase project setup, platform-specific configuration (APNs for iOS,

google-services.json

for Android), and permission handling.

For the full setup guide, see capacitor-push-notifications.

In-App Purchases

Set up in-app purchases and subscriptions with either:

Capawesome Purchases (
```
@capawesome-team/capacitor-purchases
```
) -- lightweight, no third-party backend, requires Capawesome Insiders license.
RevenueCat (
```
@revenuecat/purchases-capacitor
```
) -- full managed backend with receipt validation, analytics, and integrations.

Both require App Store Connect (iOS) and/or Google Play Console (Android) product configuration.

For the full setup guide, see capacitor-in-app-purchases.

Related Skills

capacitor-app-creation -- Create a new Capacitor app from scratch.
capacitor-app-development -- General Capacitor development topics, configuration, and troubleshooting.
capacitor-angular -- Angular-specific Capacitor patterns.
capacitor-react -- React-specific Capacitor patterns.
capacitor-vue -- Vue-specific Capacitor patterns.
capacitor-plugins -- Install and configure 160+ Capacitor plugins.
capacitor-plugin-development -- Create custom Capacitor plugins.
capacitor-app-upgrades -- Upgrade Capacitor apps across major versions.
capacitor-plugin-upgrades -- Upgrade Capacitor plugins across major versions.
capacitor-push-notifications -- Push notifications with FCM.
capacitor-in-app-purchases -- In-app purchases and subscriptions.
capawesome-cloud -- Live updates, native builds, app store publishing.
capawesome-cli -- Capawesome CLI reference.

capacitor-expert

NPX Install

Tags

SKILL.md Content

Capacitor Expert

Core Concepts

Architecture

Project Structure

Capacitor Config

Creating a New App

Quick Start

Capacitor CLI

Framework Integration

Angular

React

Vue

Plugins

Plugin Sources

Installing a Plugin

Using a Plugin

Plugin Development

Cross-Platform Best Practices

Platform Detection

Permissions

Performance

Error Handling

Deep Links

Listener Setup

Platform Configuration

Storage

Security

Testing

Unit Testing

E2E Testing

Debugging

Troubleshooting

Android

iOS

General

Upgrading

Capawesome Cloud

Getting Started

Live Updates

Native Builds

App Store Publishing

CI/CD Integration

Push Notifications

In-App Purchases

Related Skills