Flutter feature flags installation

Install the package

Required

Add the PostHog Flutter SDK to your pubspec.yaml:

pubspec.yaml
posthog_flutter: ^5.0.0

Platform 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
}

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

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: '2026-01-30',
      })
    </script>
  </head>
  <body>
    ...
  </body>
</html>

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'
    }
);

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');
}

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');
}

6
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.

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.

Resource	Description
Creating a feature flag	How to create a feature flag in PostHog
Adding feature flag code	How to check flags in your code for all platforms
Framework-specific guides	Setup guides for React Native, Next.js, Flutter, and other frameworks
How to do a phased rollout	Gradually roll out features to minimize risk
More tutorials	Other real-world examples and use cases

Flutter feature flags installation

Install the package

Platform setup

Send events

Evaluate boolean feature flags

Evaluate multivariate feature flags

Running experiments

Next steps

Community questions

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