> ## Documentation Index
> Fetch the complete documentation index at: https://vlyai-1c28d863.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# PostHog

> Open-source product analytics with session replay, feature flags, and experimentation.

[PostHog](https://posthog.com) is an open-source product analytics platform. Strong on funnels, retention, session replay, and feature flags.

<Note>
  Full walkthrough being written.
</Note>

## Common uses

* Track user actions to understand product usage
* Session replay to debug user-reported issues
* Feature flags for gradual rollouts
* A/B test experiments

## Setup

`VITE_POSTHOG_KEY` (client-visible) and `VITE_POSTHOG_HOST` in vly env vars. Server-side capture optional via `POSTHOG_API_KEY` (server-only).

## Related

<CardGroup cols={3}>
  <Card title="Mixpanel" icon="chart-bar" href="/integrations/mixpanel">
    Adjacent product analytics.
  </Card>

  <Card title="Amplitude" icon="chart-bar" href="/integrations/amplitude">
    Adjacent product analytics.
  </Card>

  <Card title="Sentry" icon="alert-triangle" href="/integrations/sentry">
    For error tracking.
  </Card>
</CardGroup>


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