launchdarkly_flutter_observability 0.2.0

The LaunchDarkly Observability and Session Replay plugin for Flutter. Get started using LaunchDarkly today!

LaunchDarkly Observability SDK for Flutter

launchdarkly_flutter_observability provides LaunchDarkly observability and session replay for Flutter through a single public facade, LDObserve: automatic and manual instrumentation for your application — including spans, logs, error reporting, feature flag correlation, and session replay.

Observability (spans, logs, errors) flows through a cross-platform Dart OpenTelemetry pipeline and works on mobile and web. Session replay uses a native bridge on mobile; web session replay is not yet available.

Early Access Preview

NB: APIs are subject to change until a 1.x version is released.

Supported platforms

Platform	Observability	Session replay
iOS	✅	✅ (native screenshot capture)
Android	✅	✅ (native screenshot capture)
Web	✅	🚧 Not yet available

Install

Add the package to your app's pubspec.yaml:

flutter pub add launchdarkly_flutter_observability

dependencies:
  launchdarkly_flutter_observability: ^0.0.0

Then fetch dependencies:

flutter pub get

On iOS, install the native pods (from your app's ios/ directory):

cd ios && pod install

No extra native setup is required for Android — Gradle resolves the plugin automatically.

Getting started

Initialize observability with LDObserve. There are two variants depending on whether you use a LaunchDarkly client. Both take an ObservabilityOptions and an optional SessionReplayOptions.

With a LaunchDarkly client

Pass your constructed LDClient to LDObserve.init. This registers the observability plugin on the client so feature flag evaluations are correlated with your telemetry, wires up the Dart OpenTelemetry pipeline, and boots the platform session replay:

import 'package:launchdarkly_flutter_client_sdk/launchdarkly_flutter_client_sdk.dart';
import 'package:launchdarkly_flutter_observability/launchdarkly_flutter_observability.dart';

final client = LDClient(
  LDConfig(
    CredentialSource.fromEnvironment(),
    AutoEnvAttributes.enabled,
  ),
  LDContextBuilder().kind('user', 'bob').build(),
);

client.start();

// Wires up observability + session replay and registers the plugin on the
// client. All instrumentation settings live on ObservabilityOptions.
LDObserve.init(
  client,
  observability: ObservabilityOptions(
    serviceName: 'flutter-sample-app',
    serviceVersion: const String.fromEnvironment('GIT_SHA',
        defaultValue: 'no-version'),
    instrumentation: InstrumentationOptions(
      networkRequests: true,
      launchTimes: true,
      debugPrint: DebugPrintSetting.always(),
    ),
  ),
  replay: const SessionReplayOptions(isEnabled: true),
);

Standalone (without a LaunchDarkly client)

If you are not using the LaunchDarkly client, pass your mobile key directly. This boots observability and session replay without registering a plugin:

import 'package:launchdarkly_flutter_observability/launchdarkly_flutter_observability.dart';

const mobileKey = String.fromEnvironment('LAUNCHDARKLY_MOBILE_KEY');

await LDObserve.initStandalone(
  mobileKey,
  observability: const ObservabilityOptions(
    serviceName: 'flutter-sample-app',
  ),
  replay: const SessionReplayOptions(
    isEnabled: true,
    privacy: PrivacyOptions(
      maskTextInputs: true,
      maskWebViews: false,
      maskLabels: false,
    ),
  ),
);

When replay is omitted, session replay is not started.

Automatic instrumentation

When enabled through InstrumentationOptions, the SDK automatically instruments:

• HTTP Requests: Outgoing HTTP requests (when InstrumentationOptions.networkRequests is enabled).
• Crash / Error Reporting: Uncaught errors captured through runZonedGuarded and FlutterError.onError.
• Feature Flag Evaluations: Evaluation events are added to your spans via the bundled hook.
• App Lifecycle / Launch Times: Session and launch-time tracking.
• debugPrint / print Capture: Console output forwarded as logs via the print-intercepting zone.

To forward uncaught errors and print/debugPrint output automatically, run your app inside a guarded zone:

runZonedGuarded(
  () {
    WidgetsFlutterBinding.ensureInitialized();

    FlutterError.onError = (details) {
      LDObserve.recordException(details.exception, stackTrace: details.stack);
    };

    runApp(const SessionReplayCapture(child: MyApp()));
  },
  (err, stack) => LDObserve.recordException(err, stackTrace: stack),
  zoneSpecification: LDObserve.zoneSpecification(),
);

Recording observability data

Use LDObserve to record spans, logs, and errors from your Dart code.

Logs

Use LDObserve.recordLog to emit a structured log record with a severity level and optional typed attributes. An optional stackTrace can be attached:

LDObserve.recordLog(
  'Checkout completed',
  severity: 'info',
  attributes: <String, Attribute>{
    'order_id': StringAttribute('ORD-9876'),
    'total': DoubleAttribute(42.99),
  },
);

LDObserve.recordLog(
  'This is an error log!',
  severity: 'error',
  stackTrace: StackTrace.current,
);

severity is a string; common levels are trace, debug, info, warn, error, and fatal. It defaults to info.

A log recorded while a span is active is automatically associated with that span through the OpenTelemetry context:

final span = LDObserve.startSpan('checkout-flow');
LDObserve.recordLog(
  'Processing on the same trace',
  severity: 'warn',
  attributes: <String, Attribute>{'source': StringAttribute('checkout')},
);
span.end();

Errors

Use LDObserve.recordException to capture an error. In Dart the stack trace is independent of the exception, so capture both together:

try {
  // something that throws
} catch (e, stack) {
  LDObserve.recordException(e, stackTrace: stack);
}

Traces

Use LDObserve.startSpan to create spans for tracing operations. Spans are backed by OpenTelemetry and must be ended when the operation completes.

final span = LDObserve.startSpan('api_request');
span.setAttribute('endpoint', StringAttribute('/api/users'));
span.setAttribute('method', StringAttribute('GET'));
span.addEvent('cache.miss');
span.setStatus(SpanStatusCode.ok);
span.end();

Nested spans

startSpan automatically creates parent-child relationships — each new span becomes a child of the currently active span:

final parent = LDObserve.startSpan('ProcessOrder');
final child = LDObserve.startSpan('ValidatePayment');
final grandchild = LDObserve.startSpan('ChargeCard');

await httpClient.post(Uri.parse('https://api.example.com/charge'));

grandchild.end();
child.end();
parent.end();

Sequential spans

End each span before starting the next so they are recorded independently rather than nested:

final span1 = LDObserve.startSpan('SequentialOperation1');
span1.setAttribute('sequence', StringAttribute('1'));
span1.end();

final span2 = LDObserve.startSpan('SequentialOperation2');
span2.setAttribute('sequence', StringAttribute('2'));
span2.end();

API reference

Method	Description
LDObserve.startSpan(name, {kind, attributes})	Start a span that nests under the current active span. Returns a Span.
LDObserve.recordLog(message, {severity, stackTrace, attributes})	Record a structured log.
LDObserve.recordException(exception, {stackTrace, attributes})	Record an error/exception.
LDObserve.shutdown()	Shut down observability. It cannot be restarted afterward.
LDObserve.zoneSpecification()	A zone spec that forwards print/debugPrint output as logs.
span.setAttribute(name, attribute)	Set a single typed attribute on a span.
span.setAttributes(map)	Set multiple attributes on a span.
span.addEvent(name, {attributes})	Record a named event on a span.
span.setStatus(SpanStatusCode)	Set the span status (ok, error, unset).
span.recordException(exception, {stackTrace, attributes})	Record an exception on the span.
span.end()	End the span.

SpanKind supports internal (default), client, server, producer, and consumer.

Attributes

Attribute values are strongly typed. Use the type-safe constructors, or Attribute.fromDynamic when the value's type is not known ahead of time:

span.setAttribute('count', IntAttribute(42));
span.setAttribute('name', StringAttribute('flutter'));
span.setAttribute('ratio', DoubleAttribute(3.14));
span.setAttribute('enabled', BooleanAttribute(true));
span.setAttribute('samples', DoubleListAttribute([3.14, 6.28]));
span.setAttribute('dynamic', Attribute.fromDynamic(someValue));

Available types: StringAttribute, IntAttribute, DoubleAttribute, BooleanAttribute, and their list variants (StringListAttribute, IntListAttribute, DoubleListAttribute, BooleanListAttribute).

Session replay

Session Replay captures screen recordings to help you understand how users interact with your application. Enable it by passing SessionReplayOptions to LDObserve.init / LDObserve.initStandalone, and wrap the part of your app you want recorded in a SessionReplayCapture widget:

runApp(const SessionReplayCapture(child: MyApp()));

On mobile, SessionReplayCapture provides Flutter-rendered screenshots to the native session replay SDK over a method channel; without it, the native SDK has no Flutter frames to record. On web, session replay is not yet available, so SessionReplayCapture is a no-op pass-through — wrapping your app with it is safe on every platform.

Privacy options

Control what is captured during a session with PrivacyOptions:

• maskTextInputs: (Default: true) Masks all text input fields.
• maskWebViews: (Default: false) Masks all web view content.
• maskLabels: (Default: false) Masks all text labels.
• maskImages: (Default: false) Masks all images.

const SessionReplayOptions(
  isEnabled: true,
  privacy: PrivacyOptions(
    maskTextInputs: true,
    maskWebViews: false,
    maskLabels: false,
    maskImages: false,
  ),
);

Per-widget masking

Beyond the screen-wide PrivacyOptions, you can redact individual widgets by wrapping them in LDMask — the Flutter equivalent of MAUI's view.LDMask(), expressed as a wrapper widget rather than a method call. The wrapped subtree's on-screen bounds are painted over in every captured frame, and the mask follows the widget as it lays out and scrolls:

LDMask(
  child: Text(creditCardNumber),
)

Use LDUnmask to exempt a subtree from global masking — the screen-wide PrivacyOptions rules such as maskTextInputs. For example, to reveal one non-sensitive field on a page where every input is masked:

// maskTextInputs masks every field; reveal just this one.
LDUnmask(
  child: TextField(controller: searchController),
)

Precedence: LDUnmask only overrides global masking — it does not override an explicit LDMask. An LDUnmask nested inside an LDMask stays masked, because an explicit per-widget mask always wins.

LDMask / LDUnmask are active on iOS and Android. On web they render their child unchanged for now, since web session replay is not yet available.

Identifying users

Use the LaunchDarkly client to identify or switch user contexts. This ties observability data to the correct user:

final userContext = LDContextBuilder()
    .kind('user', 'user-key')
    .name('Bob Smith')
    .build();
await client.identify(userContext);

Example

A complete, runnable sample app lives in example/. See its README for how to configure credentials and launch it on each platform.

LaunchDarkly overview

LaunchDarkly is a feature management platform that serves trillions of feature flags daily to help teams build better software, faster. Get started using LaunchDarkly today!

Contributing

We encourage pull requests and other contributions from the community. Check out our contributing guidelines for instructions on how to contribute to this SDK.