Flutter support reference

Use this page when you need the exact Flutter SDK behavior and option surface. For setup instructions, start with the Flutter SDK guide.

Support matrix

Area	Flutter SDK behavior
Package	`lucent_flutter`
Supported platforms	iOS and Android
Deferred platforms	Flutter Web and macOS are not in the MVP
Replay mode	Screenshot-mode mobile replay
Backend classification	`lucent-flutter` maps to `mobile_flutter`
iOS packaging	CocoaPods is verified
Android packaging	Flutter plugin with Android min SDK `23`; release apps need `android.permission.INTERNET`
Example app	`sdk-flutter-lucent/example` in the SDK repo

Replay envelope

Flutter replay is always sent as mobile screenshot replay:

{
  "snapshotSource": "mobile",
  "snapshotLibrary": "lucent-flutter",
  "snapshotMode": "screenshot"
}

The SDK captures a masked RepaintBoundary image from LucentWidget, encodes it as a mobile screenshot wireframe, and posts batches to /api/sdk/replay. The backend classifies these sessions as mobile_flutter.

Persistence and retry

Replay batches are persisted on disk before upload on iOS and Android. Failed uploads remain queued for retry.

Limit	Value
Maximum queued batch files	`100`
Maximum queued bytes	`50 MB`
Maximum queued age	`7 days`

Android also persists current in-memory replay events between flushes, so active events can survive a process restart before they become an upload batch. flush() is best effort. If the network request fails, the persisted batch stays queued and is retried later. When LucentWidget sees the app pause or become inactive, it emits Application Backgrounded and requests a flush. When the app resumes, it emits Application Became Active.

Configuration

Pass LucentConfig to Lucent().setup(...).

await Lucent().setup(
  const LucentConfig(
    publicKey: 'luc_pk_...',
    ingestBaseUrl: 'https://ingest-api.lucenthq.com',
    environment: LucentEnvironment.production,
    autoStart: true,
    remoteConfig: true,
    sessionReplaySampleRate: 1,
    privacy: LucentPrivacyConfig(
      maskAllText: true,
      maskAllImages: true,
    ),
    capture: LucentCaptureConfig(
      touches: true,
      appLifecycle: true,
      errors: true,
      unhandledRejections: true,
      nativeCrashes: true,
      logs: true,
      network: true,
    ),
    batching: LucentBatchingConfig(
      flushInterval: Duration(seconds: 10),
      maxEventsPerBatch: 500,
      maxBatchBytes: 1048576,
    ),
    replay: LucentReplayConfig(
      minimumDuration: Duration.zero,
      screenshotThrottle: Duration(seconds: 1),
      screenshotBackgroundCapture: false,
      eventTriggers: [],
    ),
    metadata: LucentMetadataConfig(
      app: 'Acme Mobile',
      namespace: 'com.acme.mobile',
      version: '1.2.3',
      build: '123',
      release: '1.2.3+123',
      properties: {'tier': 'pro'},
    ),
  ),
);

Core

Option	Default	Notes
`publicKey`	Required	Your Lucent public key. Safe to expose in client code.
`ingestBaseUrl`	`https://ingest-api.lucenthq.com`	Override only for self-hosted or internal testing.
`environment`	`LucentEnvironment.production`	Use `staging` or `development` for non-production apps.
`autoStart`	`true`	Set to `false` when you need to wait for consent.
`remoteConfig`	`true`	Fetches `/api/sdk/init` before auto-starting when enabled.
`sessionReplaySampleRate`	`1`	Clamped between `0` and `1`.

When remoteConfig is enabled, native replay waits for /api/sdk/init before auto-starting. If the request fails, the SDK falls back to local config. Remote config can disable recording, override session sample rate, update batching limits, change minimumDuration, toggle log/network telemetry, and replace eventTriggers.

Privacy

Option	Default	Notes
`privacy.maskAllText`	`true`	Masks `Text`, `RichText`, and editable text widgets by default.
`privacy.maskAllImages`	`true`	Masks rendered image widgets by default.

LucentMask forces masking for a subtree. LucentNoMask makes its subtree visible, so keep sensitive widgets outside any LucentNoMask region.

Flutter does not have browser-style CSS selectors. Review any LucentNoMask subtree carefully before shipping.

Capture

Option	Default	Captures
`capture.touches`	`true`	Pointer-down coordinates and `$touch` events.
`capture.appLifecycle`	`true`	`Application Opened`, `Application Became Active`, and `Application Backgrounded`.
`capture.errors`	`true`	Flutter framework errors.
`capture.unhandledRejections`	`true`	`PlatformDispatcher` async errors.
`capture.nativeCrashes`	`true`	Native uncaught exceptions on next launch.
`capture.logs`	`true`	`debugPrint`, `print` inside `runZoned`, and manual logs.
`capture.network`	`true`	`dart:io` network breadcrumbs inside `runZoned` and manual network breadcrumbs.

Batching

Option	Default	Notes
`batching.flushInterval`	`10 seconds`	Native flush loop interval.
`batching.maxEventsPerBatch`	`500`	Reaching this triggers a flush.
`batching.maxBatchBytes`	`1048576`	Reaching this triggers a flush.

Native code clamps flush interval, event count, and byte limits to bounded ranges so misconfiguration does not create extremely small or huge batches.

Replay

Option	Default	Notes
`replay.minimumDuration`	`Duration.zero`	Final flushes shorter than this are dropped.
`replay.screenshotThrottle`	`1 second`	How often `LucentWidget` attempts a screenshot.
`replay.screenshotBackgroundCapture`	`false`	Screenshots stop while the app is backgrounded by default.
`replay.eventTriggers`	`[]`	When set, recording starts after one of these events is tracked.

snapshotMode is not configurable. It is always screenshot.

Metadata and properties

Option	Event property
`metadata.app`	`$app_name`
`metadata.namespace`	`$app_namespace`
`metadata.version`	`$app_version`
`metadata.build`	`$app_build`
`metadata.release`	`release`
`metadata.properties`	Merged into event metadata

Use Lucent().setSessionProperties(...) and Lucent().setUserProperties(...) when values change during a session. The native payload also includes common mobile context: userAgent, language, snapshotSource, snapshotLibrary, snapshotMode, os, deviceType, and environment.

Public API

Method	Use for
`Lucent().setup(config)`	Initialize the SDK and native modules.
`Lucent().stop()`	Stop native recording, uninstall Dart hooks, and perform a final native flush.
`Lucent().track(name, properties?)`	Capture a custom event.
`Lucent().identify(user)`	Associate future events with a known user.
`Lucent().resetIdentity()`	Clear the known user and generate a new anonymous ID.
`Lucent().screen(name, properties?)`	Emit `$screen` and update replay screen context.
`Lucent().setSessionProperties(properties)`	Attach session-level properties.
`Lucent().setUserProperties(properties)`	Attach user-level properties.
`Lucent().captureLog(message, level, properties)`	Capture a manual log breadcrumb.
`Lucent().captureNetwork(...)`	Capture a manual network breadcrumb.
`Lucent().captureNetworkRequest(...)`	Wrap an async request and capture timing/status.
`Lucent().captureException(error, stackTrace?, properties?)`	Capture a handled exception.
`Lucent().addExceptionStep(message, properties?)`	Add an exception breadcrumb.
`Lucent().startSessionRecording(resumeCurrent: true)`	Resume screenshot replay.
`Lucent().stopSessionRecording()`	Pause screenshot replay and final flush.
`Lucent().isSessionReplayActive()`	Check whether replay is currently active.
`Lucent().flush(finalFlush: false)`	Flush queued events. Set `finalFlush: true` for a final flush.
`Lucent().getSessionInfo()`	Read `sessionId`, `windowId`, and recording state.
`Lucent().runZoned(body, onError?)`	Capture `print`, async errors, and `dart:io` network inside a zone.

getSessionInfo() returns sessionId, windowId, and recordingEnabled. Use runZoned(..., onError: handler) if your app already has its own top-level async error handler. LucentObserver accepts two optional callbacks:

Callback	Use for
`nameExtractor(RouteSettings settings)`	Convert route settings into a screen name. Defaults to `settings.name`.
`routeFilter(Route<dynamic>? route)`	Decide which routes should emit screens. Defaults to `route is PageRoute`.

For routers that do not expose named PageRoutes, call Lucent().screen(...) from your router listener instead.

Network privacy

Automatic network capture is limited to dart:io HttpClient traffic created inside Lucent().runZoned(...). Other HTTP clients need a wrapper or interceptor that calls captureNetworkRequest or captureNetwork. Lucent captures:

Field	Captured
HTTP method	Yes
URL origin and path	Yes
URL user info, query, and fragment	No
Status code	Yes, when available
Duration	Yes, when available
Transfer size	Yes, when available
Request headers	No
Response headers	No
Request body	No
Response body	No

Because headers and bodies are not captured, there are no per-field masking rules for them. Sanitize URLs before manual capture if a path segment contains sensitive data.

Error and crash behavior

Error source	Behavior
Flutter framework errors	Captured through `FlutterError.onError` when `capture.errors` is enabled.
Async platform errors	Captured through `PlatformDispatcher.instance.onError` when `capture.unhandledRejections` is enabled.
Handled exceptions	Capture manually with `Lucent().captureException(...)`.
Native uncaught exceptions	Stored synchronously and emitted as `$native_crash` on the next launch.

Native crash delivery is best effort. If the process cannot write the pending crash payload before termination, there may be no next-launch crash event.

Parity checklist

Capability	Flutter SDK	Notes
iOS replay	Supported	Screenshot-mode mobile replay.
Android replay	Supported	Screenshot-mode mobile replay.
Flutter Web replay	Deferred	No web/canvas capture path in the MVP.
Root replay wrapper	Supported	Use `LucentWidget`.
Route tracking	Supported	Use `LucentObserver` or `Lucent().screen(...)`.
Custom events	Supported	Use `Lucent().track(...)`.
Identify/reset	Supported	Use `LucentUser` and `resetIdentity`.
Touch capture	Supported	Pointer-down coordinate events.
Privacy defaults	Supported	Text, inputs, and images mask by default.
Logs	Supported	`debugPrint`, `print` in `runZoned`, and manual logs.
Network breadcrumbs	Supported	`dart:io` in `runZoned` plus manual APIs.
Handled errors	Supported	`captureException` and exception steps.
Native crashes	Supported	Next-launch `$native_crash`, best effort.
Persistent replay queue	Supported	iOS and Android batch queues with bounded retention.
Android current-event persistence	Supported	Current events persist between flushes.
Remote config	Supported	`/api/sdk/init` when enabled.
Event-triggered replay	Supported	`LucentReplayConfig.eventTriggers`.
CocoaPods	Supported	Verified iOS packaging path.
Swift Package Manager	Deferred	Use CocoaPods for the MVP.

Not in the Flutter MVP

These browser or React Native capabilities are not available in lucent_flutter 0.1.0:

Capability	Status
Flutter Web replay	Deferred until a web/canvas capture path exists.
CSS selector privacy rules	Not applicable to Flutter widget trees. Use `LucentMask` and `LucentNoMask`.
`networkIgnoreUrls`	Not exposed. Sanitize URLs manually before manual capture if needed.
Console level filtering	Not exposed. `debugPrint`, zoned `print`, and manual logs use the configured capture toggle.
Rage-click and dead-click detection	Browser-only today. Flutter touch capture is coordinate-level.
Alias/group APIs	Not in the Flutter MVP.
Persistent super-property registry	Not in the Flutter MVP. Use metadata, session properties, and user properties.
Source maps or native symbolication	External to the Flutter SDK docs today.
Expo/Metro tooling	React Native only.

Troubleshooting

Symptom	Check
No replay appears	Confirm `LucentWidget` wraps the app root and `sessionReplaySampleRate` is greater than `0`.
No screen names	Add named routes, customize `LucentObserver`, or call `Lucent().screen(...)` manually.
`print` logs are missing	Make sure `runApp` runs inside `Lucent().runZoned(...)`.
Network calls are missing	Confirm the client uses `dart:io` inside `runZoned`, or add manual/interceptor capture.
iOS build fails around pods	Run `flutter pub get`, then `cd ios && pod install`.
iOS SPM warnings appear	Use CocoaPods for the MVP; Swift Package Manager support is deferred.
A physical iOS device will not run	Enable Developer Mode and trust the development certificate/device pairing.
Android release uploads fail	Add `<uses-permission android:name="android.permission.INTERNET" />` to `android/app/src/main/AndroidManifest.xml`.
Android device install fails	Confirm USB debugging is enabled and the device trusts the development machine.
Replay is too sparse	Lower `replay.screenshotThrottle`, but watch bandwidth and battery use.

Get started

Browser SDK

Mobile SDK

Integrations

Configure Lucent

Signals

MCP

AI tools

Flutter support reference

Support matrix

Replay envelope

Persistence and retry

Configuration

Core

Privacy

Capture

Batching

Replay

Metadata and properties

Public API

Navigation reference

Network privacy

Error and crash behavior

Parity checklist

Not in the Flutter MVP

Troubleshooting

​Support matrix

​Replay envelope

​Persistence and retry

​Configuration

​Core

​Privacy

​Capture

​Batching

​Replay

​Metadata and properties

​Public API

​Navigation reference

​Network privacy

​Error and crash behavior

​Parity checklist

​Not in the Flutter MVP

​Troubleshooting

Support matrix

Replay envelope

Persistence and retry

Configuration

Core

Privacy

Capture

Batching

Replay

Metadata and properties

Public API

Navigation reference

Network privacy

Error and crash behavior

Parity checklist

Not in the Flutter MVP

Troubleshooting