Chapter 119 · Integration Angular
Subchapter 119.1
references/angular.mdMarkdown13 KBView on GitHub
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 (opens in a new tab).
Install posthog-js using your package manager:
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npm install --save posthog-jsyarn add posthog-jspnpm add posthog-jsbun add posthog-jsGenerate environment files for your project with ng g environments. Configure the following environment variables:
posthogKey: Your project token from your project settings (opens in a new tab).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.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:
posthog.service.ts
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// 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 (opens in a new tab) 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.
app.component.ts
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// 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 token and instance address. You can find both in your project settings (opens in a new tab).
main.ts
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// 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: '2026-01-30'
})
bootstrapApplication(AppComponent, appConfig)
.catch((err) => console.error(err));Identifying users is required. Call
posthog.identify('your-user-id')after login to link events to a known user. This is what connects frontend event captures, session replays (opens in a new tab), LLM traces (opens in a new tab), and error tracking (opens in a new tab) to the same person — and lets backend events link back too.See our guide on identifying users (opens in a new tab) for how to set this up.
Note: If you’re using Typescript, you might have some trouble getting your types to compile because we depend on
rrwebbut don’t ship all of their types. To accommodate that, you’ll need to add@rrweb/types@2.0.0-alpha.17andrrweb-snapshot@2.0.0-alpha.17as a dependency if you want your Angular compiler to typecheck correctly.Given the nature of this library, you might need to completely clear your
.npmcache 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(opens in a new tab) to understand what’s the exact version you need to depend on.
Set up a reverse proxy (recommended)
We recommend setting up a reverse proxy (opens in a new tab), so that events are less likely to be intercepted by tracking blockers.
We have our own managed reverse proxy service (opens in a new tab), which is free for all PostHog Cloud users, routes through our infrastructure, and makes setting up your proxy easy.
If you don’t want to use our managed service then there are several other options for creating a reverse proxy, including using Cloudflare (opens in a new tab), AWS Cloudfront (opens in a new tab), and Vercel (opens in a new tab).
Grouping products in one project (recommended)
If you have multiple customer-facing products (e.g. a marketing website + mobile app + web app), it’s best to install PostHog on them all and group them in one project (opens in a new tab).
This makes it possible to track users across their entire journey (e.g. from visiting your marketing website to signing up for your product), or how they use your product across multiple platforms.
Add IPs to Firewall/WAF allowlists (recommended)
For certain features like heatmaps (opens in a new tab), your Web Application Firewall (WAF) may be blocking PostHog’s requests to your site. Add these IP addresses to your WAF allowlist or rules to let PostHog access your site.
EU: 3.75.65.221, 18.197.246.42, 3.120.223.253
US: 44.205.89.55, 52.4.194.122, 44.208.188.173
These are public, stable IPs used by PostHog services (e.g., Celery tasks for snapshots).
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 2026-01-30.
To capture custom events (opens in a new tab), import posthog and call posthog.capture(). Below is an example of how to do this in a component:
app.component.ts
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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 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.
ngZone.runOutsideAngular (opens in a new tab).posthog.service.ts
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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 */
)
})
}
}To use PostHog with Angular server-side rendering (SSR), you need to:
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.
posthog.service.ts
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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(); //+
}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.
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npm install posthog-node --saveyarn add posthog-nodepnpm add posthog-nodebun add posthog-nodeThen, add the following code to the server.ts file:
server.ts
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// 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:
shutdown on the PostHog Node client to ensure all events are flushed.Using PostHog in server-side code
Angular SSR does not allow Node.js code to be bundled into client-side components. Even though resolvers and other server-side code can be written along with client-side components, you cannot use PostHog Node in those components.
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 (opens in a new tab).
Alternatively, the following tutorials can help you get started:
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