Angular experiments installation

Install the package

Required

Install the PostHog JavaScript library using your package manager:

npm install posthog-js
yarn add posthog-js
pnpm add posthog-js

Initialize PostHog

Required

In your src/main.ts, initialize PostHog using your project API key and instance address:

For Angular v17 and above, you can set up PostHog as a singleton service. To do this, start by creating and injecting a PosthogService instance.

Create a service by running ng g service services/posthog. The service should look like this:

src/main.ts
// src/app/services/posthog.service.ts
import { DestroyRef, Injectable, NgZone } from "@angular/core";
import posthog from "posthog-js";
import { environment } from "../../environments/environment";
import { Router } from "@angular/router";
@Injectable({ providedIn: "root" })
export class PosthogService {
  constructor(
    private ngZone: NgZone,
    private router: Router,
    private destroyRef: DestroyRef,
  ) {
    this.initPostHog();
  }
  private initPostHog() {
    this.ngZone.runOutsideAngular(() => {
      posthog.init(environment.posthogKey, {
        api_host: environment.posthogHost,
        defaults: '2026-01-30',
      });
    });
  }
}

The service is initialized outside of the Angular zone to reduce change detection cycles. This is important to avoid performance issues with session recording. Then, inject the service in your app's root component app.component.ts. This will make sure PostHog is initialized before any other component is rendered.

src/app/app.component.ts
// src/app/app.component.ts
import { Component } from "@angular/core";
import { RouterOutlet } from "@angular/router";
import { PosthogService } from "./services/posthog.service";
@Component({
  selector: "app-root",
  styleUrls: ["./app.component.scss"],
  template: `
    <router-outlet />`,
  imports: [RouterOutlet],
})
export class AppComponent {
  title = "angular-app";
  constructor(posthogService: PosthogService) {}
}

In your src/main.ts, initialize PostHog using your project API key and instance address. You can find both in your project settings.

src/main.ts
// src/main.ts
import { bootstrapApplication } from '@angular/platform-browser';
import { appConfig } from './app/app.config';
import { AppComponent } from './app/app.component';
import { environment } from "./environments/environment";
import posthog from 'posthog-js'
posthog.init(environment.posthogKey, {
  api_host: environment.posthogHost,
  defaults: '2025-11-30'
})
bootstrapApplication(AppComponent, appConfig)
  .catch((err) => console.error(err));

Implement your experiment

Required

Experiments run on top of our feature flags. You can define which version of your code runs based on the return value of the feature flag:

if (posthog.getFeatureFlag('your-experiment-feature-flag') === 'test') {
    // Do something differently for this user
} else {
    // It's a good idea to let control variant always be the default behaviour,
    // so if something goes wrong with flag evaluation, you don't break your app.
}

// Test that it works
posthog.featureFlags.overrideFeatureFlags({ flags: {'your-experiment-feature-flag': 'test'} })

4
Run your experiment
Required
Once you've implemented the feature flag in your code, you'll enable it for a target audience by creating a new experiment in the PostHog dashboard.

Next steps

Recommended

Now that you're running experiments, continue with the resources below to learn what else Experiments enables within the PostHog platform.

Resource	Description
Creating an experiment	How to create an experiment in PostHog
Adding experiment code	How to implement experiments for all platforms
Statistical significance	Understanding when results are meaningful
Experiment insights	How to analyze your experiment data
More tutorials	Other real-world examples and use cases

Angular experiments installation

Install the package

Initialize PostHog

Implement your experiment

Run your experiment

Next steps

Community questions

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