SvelteKit Error Tracking installation

Install with the wizard

Run this command in your project directory to add PostHog to your SvelteKit project. The wizard detects your framework, installs the SDK, and sets up your first events.

Learn more

Or set it up manually by following the rest of this guide.

  1. Install the package

    Required

    Install the PostHog JavaScript library using your package manager:

    npm install posthog-js

  2. Initialize PostHog

    Required

    If you haven't created a root layout already, create a new file called +layout.js in your src/routes folder. Check the environment is the browser, and initialize PostHog if so:

    src/routes/+layout.js
    import posthog from 'posthog-js'
    import { browser } from '$app/environment';
    import { onMount } from 'svelte';
    

    export const load = async () => {
      if (browser) {
        posthog.init(
          '<ph_project_token>',
          {
            api_host: 'https://us.i.posthog.com',
            defaults: '2026-08-30'
          }
        )
      }
    

      return
    };
    SvelteKit layout

    Learn more about SvelteKit layouts in the official documentation.

  3. Server-side setup

    Optional

    Install posthog-node using your package manager:

    npm install posthog-node --save

    Then, initialize the PostHog Node client where you'd like to use it on the server side. For example, in a load function:

    routes/+page.server.js
    import { PostHog } from 'posthog-node';
    

    export async function load() {
      const posthog = new PostHog('<ph_project_token>', { host: 'https://us.i.posthog.com' });
    

      posthog.capture({
        distinctId: 'distinct_id_of_the_user',
        event: 'event_name',
      })
    

      await posthog.shutdown()
    }
    Note

    Make sure to always call posthog.shutdown() after capturing events from the server-side. PostHog queues events into larger batches, and this call forces all batched events to be flushed immediately.

  4. Send events

    Click around and view a couple pages to generate some events. PostHog automatically captures pageviews, clicks, and other interactions for you.

    If you'd like, you can also manually capture custom events:

    JavaScript
    posthog.capture('my_custom_event', { property: 'value' })

  5. Set up client-side exception capture

    Required

    SvelteKit Hooks can be used to capture exceptions in the client and server-side.

    Capture exceptions in the handleError callback in your client-side hooks file:

    src/hooks.client.js
    import posthog from 'posthog-js';
    import type { HandleClientError } from '@sveltejs/kit';
    export const handleError = ({ error, status }: HandleClientError) => {
      // SvelteKit 2.0 offers a reliable way to check for a 404 error:
      if (status !== 404) {
          posthog.captureException(error);
      }
    };

  6. Set up server-side exception capture

    Required

    To capture exceptions on the server-side, you will also need to implement the handleError callback:

    src/hooks.server.ts
    import type { HandleServerError } from '@sveltejs/kit';
    import { PostHog } from 'posthog-node';
    const client = new PostHog(
      '<ph_project_token>',
      { host: 'https://us.i.posthog.com' }
    )
    export const handleError = async ({ error, status }: HandleServerError) => {
      if (status !== 404) {
          client.captureException(error);
          await client.shutdown();
      }
    };

  7. Verify error tracking

    Recommended
    Confirm events are being sent to PostHog
    Before proceeding, let's make sure exception events are being captured and sent to PostHog. You should see events appear in the activity feed.
    Activity feed with events
    Check for exceptions in PostHog

  8. Upload source maps

    Required

    Great, you're capturing exceptions! If you serve minified bundles, the next step is to upload source maps to generate accurate stack traces.

    Let's continue to the next section.

    Upload source maps

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