Flutter feature flags installation

  1. Install the package

    Required

    Add the PostHog Flutter SDK to your pubspec.yaml:

    pubspec.yaml
    posthog_flutter: ^5.0.0

  2. Android setup

    Required

    Add these values to your AndroidManifest.xml:

    android/app/src/main/AndroidManifest.xml
    <application>
        <activity>
            [...]
        </activity>
        <meta-data android:name="com.posthog.posthog.API_KEY" android:value="<ph_project_api_key>" />
        <meta-data android:name="com.posthog.posthog.POSTHOG_HOST" android:value="https://us.i.posthog.com" />
        <meta-data android:name="com.posthog.posthog.TRACK_APPLICATION_LIFECYCLE_EVENTS" android:value="true" />
        <meta-data android:name="com.posthog.posthog.DEBUG" android:value="true" />
    </application>

    Update the minimum Android SDK version to 21 in android/app/build.gradle:

    android/app/build.gradle
    defaultConfig {
        minSdkVersion 21
        // rest of your config
    }

  3. iOS/macOS setup

    Required

    Add these values to your Info.plist:

    ios/Runner/Info.plist
    <dict>
        [...]
        <key>com.posthog.posthog.API_KEY</key>
        <string><ph_project_api_key></string>
        <key>com.posthog.posthog.POSTHOG_HOST</key>
        <string>https://us.i.posthog.com</string>
        <key>com.posthog.posthog.CAPTURE_APPLICATION_LIFECYCLE_EVENTS</key>
        <true/>
        <key>com.posthog.posthog.DEBUG</key>
        <true/>
    </dict>

    Update the minimum platform version to iOS 13.0 in your Podfile:

    Podfile
    platform :ios, '13.0'
    # rest of your config

  4. Web setup

    Add these values in index.html:

    web/index.html
    <!DOCTYPE html>
    <html>
        <head>
            ...
            <script>
                !function(t,e){var o,n,p,r;e.__SV||(window.posthog=e,e._i=[],e.init=function(i,s,a){function g(t,e){var o=e.split(".");2==o.length&&(t=t[o[0]],e=o[1]),t[e]=function(){t.push([e].concat(Array.prototype.slice.call(arguments,0)))}}(p=t.createElement("script")).type="text/javascript",p.async=!0,p.src=s.api_host.replace(".i.posthog.com","-assets.i.posthog.com")+"/static/array.js",(r=t.getElementsByTagName("script")[0]).parentNode.insertBefore(p,r);var u=e;for(void 0!==a?u=e[a]=[]:a="posthog",u.people=u.people||[],u.toString=function(t){var e="posthog";return"posthog"!==a&&(e+="."+a),t||(e+=" (stub)"),e},u.people.toString=function(){return u.toString(1)+".people (stub)"},o="init capture register register_once register_for_session unregister opt_out_capturing has_opted_out_capturing opt_in_capturing reset isFeatureEnabled getFeatureFlag getFeatureFlagPayload reloadFeatureFlags group identify setPersonProperties setPersonPropertiesForFlags resetPersonPropertiesForFlags setGroupPropertiesForFlags resetGroupPropertiesForFlags resetGroups onFeatureFlags addFeatureFlagsHandler onSessionId getSurveys getActiveMatchingSurveys renderSurvey canRenderSurvey getNextSurveyStep".split(" "),n=0;n<o.length;n++)g(u,o[n]);e._i.push([i,s,a])},e.__SV=1)}(document,window.posthog||[]);
                posthog.init('<ph_project_api_key>', {
                    api_host: 'https://us.i.posthog.com',
                    defaults: '2025-11-30',
                })
            </script>
        </head>
        <body>
            ...
        </body>
    </html>

  5. Send events

    Recommended

    Once installed, PostHog will automatically start capturing events. You can also manually send events to test your integration:

    Dart
    import 'package:posthog_flutter/posthog_flutter.dart';
    

    await Posthog().capture(
        eventName: 'button_clicked',
        properties: {
          'button_name': 'signup'
        }
    );

    By default, for backwards compatibility reasons, events are sent with person profile processing enabled. This means a person profile will be created for each user who triggers an event.

    If you want to disable person profile processing for certain events, send the event with the following property:

    Dart
    "$process_person_profile": false

  6. Evaluate boolean feature flags

    Required

    Check if a feature flag is enabled:

    Dart
    final isMyFlagEnabled = await Posthog().isFeatureEnabled('flag-key');
    if (isMyFlagEnabled) {
        // Do something differently for this user
        // Optional: fetch the payload
        final matchedFlagPayload = await Posthog().getFeatureFlagPayload('flag-key');
    }

  7. Evaluate multivariate feature flags

    Optional

    For multivariate flags, check which variant the user has been assigned:

    Dart
    final enabledVariant = await Posthog().getFeatureFlag('flag-key');
    if (enabledVariant == 'variant-key') { // replace 'variant-key' with the key of your variant
        // Do something differently for this user
        // Optional: fetch the payload
        final matchedFlagPayload = await Posthog().getFeatureFlagPayload('flag-key');
    }

  8. Running experiments

    Optional

    Experiments run on top of our feature flags. Once you've implemented the flag in your code, you run an experiment by creating a new experiment in the PostHog dashboard.

  9. Next steps

    Recommended

    Now that you're evaluating flags, continue with the resources below to learn what else Feature Flags enables within the PostHog platform.

    ResourceDescription
    Creating a feature flagHow to create a feature flag in PostHog
    Adding feature flag codeHow to check flags in your code for all platforms
    Framework-specific guidesSetup guides for React Native, Next.js, Flutter, and other frameworks
    How to do a phased rolloutGradually roll out features to minimize risk
    More tutorialsOther real-world examples and use cases

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