Nuxt.js (v3.0 to v3.6)

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

These docs are for Nuxt v3.0 to v3.6. You can see a working example of the Nuxt v3.0 integration in our Nuxt.js demo app

Setting up PostHog on the client side

1. Install posthog-js using your package manager:

npm install --save posthog-js

yarn add posthog-js

pnpm add posthog-js

bun add posthog-js

If your site sets a Content-Security-Policy, it needs to allow PostHog. This applies to the snippet and to package installs alike: the SDK lazy-loads extra bundles (session replay, surveys) from PostHog's CDN, and sends events to the ingestion host. PostHog serves from subdomains of posthog.com that change over time, so allow the wildcard:

PostHog AI

script-src 'self' https://*.posthog.com;
connect-src 'self' https://*.posthog.com;
worker-src 'self' blob: data:;

script-src covers the snippet and the lazy-loaded bundles, connect-src covers event ingestion and feature flags, and worker-src covers session replay. The toolbar needs a few more, or use a reverse proxy so everything is first-party. Failing to do so causes silent failures where capture and identify calls never send, so the integration looks complete while zero events arrive. Remember connect-src falls back to default-src, so default-src 'self' blocks event delivery even when the script itself is bundled.

2. Store your PostHog key and host in environment variables rather than hard-coding them. Add them to a .env file (and to your hosting provider). You can find these in your project settings.

NUXT_PUBLIC_POSTHOG_PROJECT_TOKEN=<ph_project_token>
NUXT_PUBLIC_POSTHOG_HOST=https://us.i.posthog.com

Then reference them in your nuxt.config.js file:

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      posthogToken: process.env.NUXT_PUBLIC_POSTHOG_PROJECT_TOKEN || '<ph_project_token>',
      posthogHost: process.env.NUXT_PUBLIC_POSTHOG_HOST || 'https://us.i.posthog.com',
      posthogDefaults: '2026-05-30',
    },
  }
})

3. Create a new plugin by creating a new file posthog.client.js in your plugins directory.

import { defineNuxtPlugin, useRuntimeConfig } from '#imports'

import posthog from 'posthog-js'

export default defineNuxtPlugin(() => {
  const runtimeConfig = useRuntimeConfig()
  const posthogClient = posthog.init(runtimeConfig.public.posthogToken, {
    api_host: runtimeConfig.public.posthogHost,
    defaults: runtimeConfig.public.posthogDefaults,
    loaded: (posthog) => {
      if (import.meta.env.MODE === 'development') posthog.debug()
    },
  })

  return {
    provide: {
      posthog: () => posthogClient,
    },
  }
})

PostHog can then be accessed throughout your Nuxt.js using the provider accessor, for example:

<script setup>
   const { $posthog } = useNuxtApp()
   if ($posthog) {
      const posthog = $posthog()
      posthog.capture('<event_name>')
   }
</script>

See the JavaScript SDK docs for all usable functions, such as:

• Capture custom event capture, identify users, and more.
• Feature flags including variants and payloads.

If your app calls your own backend, tracing_headers adds X-POSTHOG-DISTINCT-ID and X-POSTHOG-SESSION-ID to matching fetch and XMLHttpRequest requests. This lets server-side SDKs link backend events, errors, and LLM traces back to frontend sessions and replays. Use hostnames only, without protocols or paths.

posthog.init('<ph_project_token>', {
  api_host: 'https://us.i.posthog.com',
  // Optional: send PostHog session/user context to your backend
  tracing_headers: ['api.example.com'],
})

This works in local development too, but match on the hostname alone: use 'localhost', not 'localhost:3000'. Ports are never part of a hostname, so a value with one in it never matches anything. localhost and 127.0.0.1 are also different hostnames — use whichever your app actually calls.

Tracing headers help you attribute events across front and backend consistently. When this isn't available, use your server-side stable IDs to deduce the matching distinctId, and pass it in when capturing the event.

Setting up PostHog on the server side

Install posthog-node using your package manager:

npm install posthog-node --save

yarn add posthog-node

pnpm add posthog-node

bun add posthog-node

Add your PostHog API key and host to your nuxt.config.js file, reading them from environment variables. If you've already done this when adding PostHog to the client side, you can skip this step.

export default defineNuxtConfig({
  runtimeConfig: {
    public: {
      posthogToken: process.env.NUXT_PUBLIC_POSTHOG_PROJECT_TOKEN || '<ph_project_token>',
      posthogHost: process.env.NUXT_PUBLIC_POSTHOG_HOST || 'https://us.i.posthog.com',
      posthogDefaults: '2026-05-30',
    }
  }
})

Initialize the PostHog Node client where you'd like to use it on the server side. For example, in a server route:

Show full example
  const runtimeConfig = useRuntimeConfig()

  const posthog = new PostHog(
    runtimeConfig.public.posthogToken,
    { 
      host: runtimeConfig.public.posthogHost, 
    }
  );

  posthog.capture({
    event: 'api_call',
    distinctId: distinctID,
    properties: {
      $current_url: url,
      query: query
    }
  })
  posthog.shutdown()

  return {
    message: "example response"
Show full example

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.

See the Node SDK docs for all usable functions, such as:

• Capture custom event capture, identify users, and more.
• Feature flags including variants and payloads.

Next steps

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

Alternatively, the following tutorials can help you get started:

• How to set up analytics in Nuxt
• How to set up feature flags in Nuxt
• How to set up A/B tests in Nuxt
• How to set up surveys in Nuxt