PostHog

---
description: PostHog analytics conventions
globs: ["src/**/*.ts", "src/**/*.tsx"]
alwaysApply: false
---

# PostHog

## Event naming

`object_action`, past tense, snake_case:

```ts
posthog.capture('subscription_started', { plan: 'annual', source: 'paywall' });
```

- Never put a value in the name. `plan_selected` with a `plan` property, not
  `plan_selected_annual`.
- Never invent a second convention. Renaming events later does not backfill
  history, so inconsistency is permanent.

## What to track

- Track decisions and outcomes, not every tap. If you cannot name the question
  an event answers, do not add it.
- Analytics calls go through `src/services/analytics/`, never directly from a
  component.

## Privacy

- No personal data in properties: no email, name, phone number, address, or
  message content.
- Identify by internal user id only.
- `posthog.reset()` on sign-out — without it the next user on a shared device
  inherits the previous person's identity.

## Feature flags

- Never block first render on a flag. Render the default and update when the
  flag arrives.
- Always handle the "flag unavailable" case explicitly; the fetch can fail.
- Remove a flag from the code once it has fully rolled out. Stale flags become
  permanent dead branches.

## Never

- Never let an analytics failure break a user flow. Wrap it, and let it fail
  silently.
- Never send an event containing a token, key or session id.
- Never point a development build at the production project.