Svelte

1. 1

   Install the package

   Required

   Install the PostHog JavaScript library using your package manager:

   npm

   bashCopy

   npm install posthog-js

   yarn

   bashCopy

   yarn add posthog-js

   pnpm

   bashCopy

   pnpm add posthog-js

   bun

   bashCopy

   bun add posthog-js

2. 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

   javascriptCopy

   import posthog from 'posthog-js'
   import { browser } from '$app/environment';
   import { onMount } from 'svelte';
   
   export const load
   
   
   
   
   
   
   
   
   
   
   
   

3. 3

   Server-side setup

   Optional

   Install posthog-node using your package manager:

   npm

   bashCopy

   npm install posthog-node --save

   yarn

4. 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

   javascriptCopy

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

5. 5

   Set up client-side exception capture

   Required

   SvelteKit Hooks (opens in a new tab) 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

   javascriptCopy

   import posthog from 'posthog-js';
   import type { HandleClientError } from '@sveltejs/kit';
   
   
   
   
   
   

6. 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

   javascriptCopy

   import type { HandleServerError } from '@sveltejs/kit';
   import { PostHog } from 'posthog-node';
   const client = new PostHog(
   
   
   
   
   
   
   
   
   

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.

   

   Check for exceptions in PostHog (opens in a new tab)

8. 7

   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 (opens in a new tab)

Still have questions?

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SvelteKit layout

Learn more about SvelteKit layouts (opens in a new tab) in the official documentation.

pnpm

bun

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

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.