@capgo/capgo-skills
capacitor-deep-linking
Implements and debugs deep links in Capacitor apps - custom URL schemes, iOS Universal Links (apple-app-site-association, Associated Domains entitlement), Android App Links (assetlinks.json, autoVerify), and routing via @capacitor/app `appUrlOpen` + `App.getLaunchUrl()`. Covers the Capacitor 8.5+ UIScene change where AppDelegate `application(_:open:options:)` and `continue userActivity` stop being called and custom handling must move to SceneDelegate, plus cold vs warm launch testing. Use when links open Safari/Chrome instead of the app, `appUrlOpen` never fires, the launch URL is lost on cold start, or OAuth redirects do not return to the app. Do not use for the full UIScene migration (capacitor-uiscene-migration), push notification taps (capacitor-push-notifications), or social login plugin setup (capacitor-plugins).
Deep Linking in Capacitor
Route custom-scheme links, iOS Universal Links, and Android App Links into the web app.
When to Use
TRIGGER when:
- Adding myapp:// schemes, Universal Links, or App Links to a Capacitor app
- Links open the browser instead of the app, or open the app but land on the home page
- appUrlOpen fires on warm open but the URL is missing on cold launch (or the reverse)
- Deep links broke after updating to Capacitor 8.5+ / adopting SceneDelegate.swift
- OAuth / magic-link / payment redirects must come back into the app
- adb shell pm get-app-links shows none or 1024 instead of verified
Do not use:
- Full AppDelegate -> SceneDelegate migration of an app: capacitor-uiscene-migration
- Notification tap routing: capacitor-push-notifications
- Native log capture while debugging: ios-android-logs
- Sign in with Apple / Google plugin config: capacitor-plugins
Link Types
| Type | Platform | Format | Needs hosted file | Verified ownership |
|---|---|---|---|---|
| Custom scheme | both | myapp://product/123 | no | no (any app can claim it) |
| Universal Links | iOS | https://example.com/product/123 | /.well-known/apple-app-site-association | yes |
| App Links | Android 6+ | https://example.com/product/123 | /.well-known/assetlinks.json | yes |
Prefer verified https links for anything security-sensitive (OAuth, magic links). Custom schemes can be hijacked by another app.
Workflow
- Inspect first. Read capacitor.config.*, ios/App/App/Info.plist, ios/App/App/*.entitlements, ios/App/App/AppDelegate.swift, ios/App/App/SceneDelegate.swift (if present), android/app/src/main/AndroidManifest.xml, and the @capacitor/app version in package.json.
- Decide the iOS lifecycle path.
- UIApplicationSceneManifest present in Info.plist (Capacitor 8.5+ template or migrated app) -> URL events arrive in SceneDelegate. Any custom code in AppDelegate application(_:open:options:) or application(_:continue:restorationHandler:) is dead code. See references/ios-scene-delegate.md.
- No scene manifest -> AppDelegate path still works on 8.5 core, but Xcode 27 / Capacitor 9 require the scene lifecycle. Hand the migration to capacitor-uiscene-migration.
- Install @capacitor/app (npm install @capacitor/app && npx cap sync).
- Register the JS handler once, at app bootstrap (before the router renders), using both appUrlOpen and getLaunchUrl(). See below.
- Configure platforms: custom scheme (Info.plist CFBundleURLTypes, Android <intent-filter>), then verified links per platform:
- iOS Universal Links: references/ios-universal-links.md
- Android App Links: references/android-app-links.md
- Route in the framework router: references/routing-patterns.md (React, Vue, Angular, OAuth callbacks, deferred links).
- Verify with the cold/warm matrix below on a real device.
Only load a reference when its topic is in play.
JS Handler (the part every app needs)
import { App, type URLOpenListenerEvent } from '@capacitor/app';
let lastHandled: string | undefined;
function route(rawUrl: string) {
if (rawUrl === lastHandled) return; // cold start can deliver the same URL to both paths
lastHandled = rawUrl;
const url = new URL(rawUrl);
// myapp://product/123 -> host "product", pathname "/123"
// https://example.com/product/123 -> pathname "/product/123"
const path = url.protocol.startsWith('http')
? url.pathname
: `/${url.host}${url.pathname}`;
router.navigate(path + url.search); // your router
}
export async function initDeepLinks() {
await App.addListener('appUrlOpen', (event: URLOpenListenerEvent) => route(event.url));
const launch = await App.getLaunchUrl(); // resolves undefined or { url }
if (launch?.url) route(launch.url);
}Traps:
- Custom scheme URLs parse with the first segment as host, not pathname. Normalize both forms as above.
- Register the listener at bootstrap, not inside a lazily loaded page. A listener added after the event fired never sees it; getLaunchUrl() is the fallback for cold start.
- Wrap state updates from the listener in your framework's zone/run loop (Angular NgZone.run) or navigation silently does nothing.
- Dedupe: on cold start the URL can be reachable via both getLaunchUrl() and appUrlOpen.
- Validate and allow-list paths before navigating; a deep link is untrusted input.
Custom Scheme Config
iOS ios/App/App/Info.plist:
<key>CFBundleURLTypes</key>
<array>
<dict>
<key>CFBundleURLName</key>
<string>com.example.app</string>
<key>CFBundleURLSchemes</key>
<array><string>myapp</string></array>
</dict>
</array>Android AndroidManifest.xml, inside the existing MainActivity (keep the template's android:launchMode="singleTask" so warm opens reuse the activity):
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="myapp" />
</intent-filter>Verification
Run every row on a physical device (Universal Links do not work reliably from the Simulator address bar; tap from Notes/Messages instead).
| Scenario | iOS | Android |
|---|---|---|
| Custom scheme, warm | xcrun simctl openurl booted "myapp://product/123" | adb shell am start -W -a android.intent.action.VIEW -d "myapp://product/123" com.example.app |
| Custom scheme, cold | kill app, then same command | adb shell am force-stop com.example.app, then same command |
| Verified link, warm | tap https://example.com/product/123 in Notes | adb shell am start -W -a android.intent.action.VIEW -c android.intent.category.BROWSABLE -d "https://example.com/product/123" |
| Verified link, cold | swipe app away, tap link | force-stop, then same command |
| Ownership check | curl -sI https://example.com/.well-known/apple-app-site-association (200, no redirect) | adb shell pm get-app-links com.example.app shows verified |
Pass criteria: each case lands on the right route, appUrlOpen logs once, and on cold start getLaunchUrl() returns the URL. After a Capacitor 8.5 scene migration, re-run the full matrix: cold launch takes a different native path (scene(_:willConnectTo:options:)) than warm open (scene(_:openURLContexts:) / scene(_:continue:)).
Grep for dead handlers after migration:
grep -n "open url: URL\|continue userActivity" ios/App/App/AppDelegate.swift
grep -n "SceneDelegateProxy" ios/App/App/SceneDelegate.swiftError Handling
| Symptom / message | Cause | Fix |
|---|---|---|
| Link opens in Safari, app installed | AASA not fetched, wrong appID, entitlement missing, or user long-pressed and chose "Open in Safari" | Check AASA via Apple CDN, TEAMID.bundleId, applinks: entitlement; long-press link and choose "Open in App" to reset |
| Custom AppDelegate URL code stopped running after 8.5 update | Scene manifest exists; iOS calls SceneDelegate instead | Move logic to SceneDelegate (reference: ios-scene-delegate) |
| Warm opens work, cold launch lands on home | Listener registered late, or custom SceneDelegate code ignores connectionOptions | Call getLaunchUrl() at bootstrap; keep SceneDelegateProxy.shared.scene(_:willConnectTo:options:) |
| Safari cannot open the page because the address is invalid | Custom scheme not registered in installed build | Add CFBundleURLTypes, rebuild (not just cap sync) |
| Error: Activity not started, unable to resolve Intent | No intent-filter matches scheme/host | Fix <data> entries; reinstall app |
| pm get-app-links shows 1024 or none | assetlinks.json unreachable, wrong package, or wrong SHA-256 (often the Play App Signing key) | Fix file, then adb shell pm verify-app-links --re-verify com.example.app |
| Android shows app chooser for https link | Domain not verified (autoVerify missing or failed) | Add android:autoVerify="true", re-verify |
| OAuth redirect returns to browser tab, not app | Redirect URI does not match registered scheme / verified domain | Register exact redirect URI; prefer verified https link |
Resources
- Capacitor deep links guide: https://capacitorjs.com/docs/guides/deep-links
- App plugin API: https://capacitorjs.com/docs/apis/app
- Updating to 8.5 (UIScene): https://capacitorjs.com/docs/updating/8-5
- Apple Universal Links: https://developer.apple.com/documentation/xcode/supporting-associated-domains
- Android App Links: https://developer.android.com/training/app-links/verify-android-applinks