React Router V7 Declarative Mode

1. 1

   Install client-side SDKs

   Required

   First, you’ll need to install posthog-js (opens in a new tab) and @posthog/react using your package manager. These packages allow you to capture client-side events.

   PostHog AI

   npm

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   npm install --save posthog-js @posthog/react

   Yarn

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   yarn add posthog-js @posthog/react

   pnpm

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   pnpm add posthog-js @posthog/react

   Bun

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   bun add posthog-js @posthog/react

2. 2

   Add your environment variables

   Required

   Add your environment variables to your .env.local file and to your hosting provider (e.g. Vercel, Netlify, AWS). You can find your project token and host in your project settings (opens in a new tab). If you’re using Vite, including VITE_PUBLIC_ in their names ensures they are accessible in the frontend.

   .env.local

   PostHog AI

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   VITE_PUBLIC_POSTHOG_TOKEN=<ph_project_token>
   VITE_PUBLIC_POSTHOG_HOST=https://us.i.posthog.com

3. 3

   Add the PostHogProvider to your app

   Required

   In declarative mode, you’ll need to wrap your BrowserRouter with the PostHogProvider context. This passes an initialized PostHog client to your app.

   src/main.tsx

   PostHog AI

   jsxCopy

   import { StrictMode } from "react";
   import ReactDOM from "react-dom/client";
   import
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

4. Verify client-side events are captured

   Checkpoint

   Confirm that you can capture client-side events and see them in your PostHog project

   At this point, you should be able to capture client-side events and see them in your PostHog project. This includes basic events like page views and button clicks that are autocaptured (opens in a new tab).

   You can also try to capture a custom event to verify it’s working. You can access PostHog in any component using the usePostHog hook.

   TSX

   PostHog AI

   jsxCopy

   import { usePostHog } from '@posthog/react'
   function App() {
   
   
   

5. 4

   Access PostHog methods

   Required

   On the client-side, you can access the PostHog client using the usePostHog hook. This hook returns the initialized PostHog client, which you can use to call PostHog methods. For example:

   TSX

   PostHog AI

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   import { usePostHog } from '@posthog/react'
   function App() {
     const posthog = usePostHog()
     return <button onClick={() =>
   

6. 5

   Identify your user

   Recommended

   Now that you can capture basic client-side events, you’ll want to identify your user so you can associate users with captured events.

   Generally, you identify users when they log in or when they input some identifiable information (e.g. email, name, etc.). You can identify users by calling the identify method on the PostHog client:

   TSX

   PostHog AI

   jsxCopy

   export default function Login() {
     const { user, login } = useAuth
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

7. 6

   Create an error boundary

   Recommended

   PostHog can capture exceptions thrown in your app through an error boundary. PostHog provides a PostHogErrorBoundary component that you can use to capture exceptions. You can wrap your app with this component to capture exceptions.

   TSX

   PostHog AI

   jsxCopy

   ReactDOM.createRoot(root).render(
     <StrictMode>
       <PostHogProvider client={posthog}>
       <
   
   
   
   
   
   
   
   
   
   
   

8. 7

   Tracking element visibility

   Recommended

   The PostHogCaptureOnViewed component enables you to automatically capture events when elements scroll into view in the browser. This is useful for tracking impressions of important content, monitoring user engagement with specific sections, or understanding which parts of your page users are actually seeing.

   The component wraps your content and sends a $element_viewed event to PostHog when the wrapped element becomes visible in the viewport. It only fires once per component instance.

   Basic usage:

   React

   PostHog AI

   jsxCopy

   import { PostHogCaptureOnViewed } from '@posthog/react'
   function App() {
       return (
           <PostHogCaptureOnViewed name
   
   
   
   

9. 8

   Set up server-side analytics

   Recommended

   Now that you’ve set up PostHog for React Router V7 in declarative mode, you can continue to set up server-side analytics. You can find our other SDKs in the SDKs page (opens in a new tab).

   To help PostHog track your user sessions across the client and server, you’ll need to add the __add_tracing_headers: ['your-backend-domain1.com', 'your-backend-domain2.com', ...] option to your PostHog initialization:

   TSX

   PostHog AI

   jsxCopy

   posthog.init(import.meta.env.VITE_PUBLIC_POSTHOG_TOKEN, {
   
   
   
   

10. 9

    Next steps

    Recommended

    Now that you’ve set up PostHog for React Router, you can start capturing events and exceptions in your app.

    To get the most out of PostHog, you should familiarize yourself with the following:

    • PostHog Web SDK docs (opens in a new tab): Learn more about the PostHog Web SDK and how to use it on the client-side.
    • PostHog Node SDK docs (opens in a new tab): Learn more about the PostHog Node SDK and how to use it on the server-side.
    • Identify users: Learn more about how to identify users in your app.

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This initializes PostHog and passes it to your app through the PostHogProvider context.

TypeError: Cannot read properties of undefined

If you see the error TypeError: Cannot read properties of undefined (reading '...') this is likely because you tried to call a posthog function when posthog was not initialized (such as during the initial render). On purpose, we still render the children even if PostHog is not initialized so that your app still loads even if PostHog can’t load.

To fix this error, add a check that posthog has been initialized such as:

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Typescript helps protect against these errors.

You should see these events in a minute or two in the activity tab (opens in a new tab).

For a complete list of available methods, see the posthog-js documentation (opens in a new tab).

PostHog automatically generates anonymous IDs for users before they’re identified. When you call identify, a new identified person is created. All previous events tracked with the anonymous ID link to the new identified distinct ID, and all future captures on the same browser associate with the identified person.

This automatically captures exceptions thrown in your React Router app using the posthog.captureException() method.

With custom properties:

You can include additional properties with the event to provide more context:

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Tracking multiple children:

Use trackAllChildren to track each child element separately. This is useful for galleries or lists where you want to know which specific items were viewed:

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When trackAllChildren is enabled, each child element sends its own event with a child_index property indicating its position.

Custom intersection observer options:

You can customize when elements are considered “viewed” by passing options to the IntersectionObserver:

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The component passes all other props to the wrapper div, so you can add styling, classes, or other HTML attributes as needed.

This adds the X-POSTHOG-DISTINCT-ID and X-POSTHOG-SESSION-ID headers to your requests, which you can later use on the server-side.