Angular

PostHog makes it easy to get data about traffic and usage of your Angular app. Integrating PostHog into your site enables analytics about user behavior, custom events capture, session recordings, feature flags, and more.

This guide walks you through integrating PostHog into your Angular app using the JavaScript Web SDK.

Installation

Install posthog-js using your package manager:

npm install --save posthog-js

Initialize the PostHog client

Generate environment files for your project with ng g environments. Configure the following environment variables:

• posthogKey: Your project API key from your project settings.
• posthogHost: Your project's client API host. Usually https://us.i.posthog.com for US-based projects and https://eu.i.posthog.com for EU-based projects.

// 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: '2025-05-24',
      });
    });
  }
}

// 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) {}
}

Note: If you're using Typescript, you might have some trouble getting your types to compile because we depend on rrweb but don't ship all of their types. To accommodate that, you'll need to add @rrweb/types@2.0.0-alpha.17 and rrweb-snapshot@2.0.0-alpha.17 as a dependency if you want your Angular compiler to typecheck correctly.

Given the nature of this library, you might need to completely clear your .npm cache to get this to work as expected. Make sure your clear your CI's cache as well.

In the rare case the versions above get out-of-date, you can check our JavaScript SDK's package.json to understand what's the exact version you need to depend on.

Tracking pageviews

PostHog automatically tracks your pageviews by hooking up to the browser's navigator API as long as you initialize PostHog with the defaults config option set after 2025-05-24.

Capture custom events

To capture custom events, import posthog and call posthog.capture(). Below is an example of how to do this in a component:

import { Component } from '@angular/core';
import posthog from 'posthog-js'

@Component({
 // existing component code
})

export class AppComponent {
  handleClick() {
    posthog.capture(
      'home_button_clicked', 
    )
  }
}

Session replay

Session replay uses change detection to record the DOM. This can clash with Angular's change detection.

The recorder tool attempts to detect when an Angular zone is present and avoid the clash but might not always succeed.

• If you followed the installation instructions for Angular v17 and above, you don't need to do anything.
• If you followed the installation instructions for Angular v16 and below and you see performance impact from recording in an Angular project, ensure that you use ngZone.runOutsideAngular.

import { Injectable } from '@angular/core';
import posthog from 'posthog-js'

@Injectable({ providedIn: 'root' })
export class PostHogSessionRecordingService {
  constructor(private ngZone: NgZone) {}
initPostHog() {
    this.ngZone.runOutsideAngular(() => {
      posthog.init(
        /* your config */
      )
    })
  }
}

Angular with SSR

To use PostHog with Angular server-side rendering (SSR), you need to:

1. Update the PostHog web JS client to only initialize on the client-side.
2. Initialize PostHog Node on the server-side.

1. Update the PostHog web JS client

Update your posthog.service.ts to restrict the initialization of the PostHog web JS client to the client-side. The web SDK uses methods that are not available on the server side, so we need to check if we're on the client side before initializing PostHog.

Show full example
import { isPlatformBrowser } from "@angular/common"; 
import { PLATFORM_ID } from "@angular/core"; 
import { isPlatformBrowser } from "@angular/common"; 
import { PLATFORM_ID } from "@angular/core"; 

@Injectable({ providedIn: "root" })
export class PosthogService {
  constructor(
    private ngZone: NgZone,
    private router: Router,
    private destroyRef: DestroyRef,
    @Inject(PLATFORM_ID) private platformId: Object 
  ) {
    // Only initialize PostHog in browser environment
    if (isPlatformBrowser(this.platformId)) { 
      this.initPostHog(); //+
    } 
Show full example

2. Add server-side initialization

Angular SSR uses a server.ts file to handle requests. We can add any server-side initialization code to this file.

First, install the posthog-node package to run on the server side.

npm install posthog-node --save

Then, add the following code to the server.ts file:

// src/server.ts

import { environment } from './environments/environment';
import { PostHog } from 'posthog-node'

/**
 * Extract distinct ID from PostHog cookie
 */
function getDistinctIdFromCookie(cookieHeader: string | undefined): string | null {
  if (!cookieHeader) return null;
  
  const cookieMatch = cookieHeader.match(`ph_${environment.posthogKey}_posthog=([^;]+)`);
  if (cookieMatch) {
    try {
      const parsed = JSON.parse(decodeURIComponent(cookieMatch[1]));
      return parsed?.distinct_id || null;
    } catch (error) {
      console.error('Error parsing PostHog cookie:', error);
      return null;
    }
  }
  return null;
}

/**
 * Handle all other requests by rendering the Angular application.
 */
app.get('**', async (req, res, next) => {
  const { protocol, originalUrl, baseUrl, headers } = req;

  const distinctId = getDistinctIdFromCookie(headers.cookie);
  let isFeatureEnabled = false;
  const client = new PostHog(
      const client = new PostHog(
      environment.posthogKey,
      { host: environment.posthogHost }
  )
  )

  if (distinctId) {
    client.capture({
      distinctId: distinctId,
      event: 'test_ssr_event',
      properties: {
        message: 'Hello from Angular SSR!'
      }
    })

    isFeatureEnabled = await client.isFeatureEnabled(
      'your_feature_flag_key', distinctId) || false;
  }

  commonEngine
    .render({
      bootstrap,
      documentFilePath: indexHtml,
      url: `${protocol}://${headers.host}${originalUrl}`,
      publicPath: browserDistFolder,
      providers: [
        { provide: APP_BASE_HREF, useValue: baseUrl },
        { provide: 'FEATURE_FLAG_ENABLED', useValue: isFeatureEnabled }
      ],
    })
    .then((html) => res.send(html))
    .catch((err) => next(err));

  await client.shutdown() 
});

This code does the following:

• Extracts the distinct ID from the cookie header. This is set by the web JS client.
• Captures an event on the server side.
• Evaluates a feature flag on the server side. This can be passed as a provider to the Angular application.
• Calls shutdown on the PostHog Node client to ensure all events are flushed.

Next steps

For any technical questions for how to integrate specific PostHog features into Angular (such as feature flags, A/B testing, surveys, etc.), have a look at our JavaScript Web SDK docs.

Alternatively, the following tutorials can help you get started:

• How to set up Angular analytics, feature flags, and more
• How to set up A/B tests in Angular
• How to set up surveys in Angular