Event Tracking (PostHog Facade)

Status: Shipped — vendor-agnostic facade over posthog-node. Last reviewed: 2026-05-28

What

A minimal, vendor-neutral analytics facade exposed as the global EventTrackingService. Today it wraps the PostHog Node SDK; the public methods (track, identify) keep callers from binding to PostHog directly.

Specifically NOT in this feature:

• No DB log of events (PostHog is the system of record).
• No webhook ingestion from PostHog back into FitKit.
• No client-side capture from web (PostHog browser SDK is configured separately, not in this module).
• No A/B testing / feature flag plumbing.

Why

• Funnel analytics: announcement publishes, signups, conversions, payments.
• Decouple call sites from the vendor — swapping to Segment / Amplitude / Snowflake would touch one file.
• Production-only by design — local dev events would pollute funnels. Non-prod runs as a log-only no-op.

Personas

System-internal. No user-facing surface. The data product team consumes PostHog dashboards.

Capabilities

• track(distinctId, event, properties?) — fire-and-forget capture. Logs at info level always; sends to PostHog when configured + in production.
• identify(distinctId, properties?) — set / update PostHog person properties.
• Auto-flush — 20-event batch or 10s interval (PostHog SDK defaults overridden).
• Lifecycle — onModuleDestroy shuts down the PostHog client; flushes pending events on app stop.

Capabilities (gaps)

• No backend-side queue between API call and PostHog send — a slow PostHog wouldn’t block (try/catch), but events could be lost on shutdown if onModuleDestroy doesn’t flush in time.
• No structured event taxonomy enforcement (any string event name accepted). Event names today: announcement_published, payment-related events from PaymentObservabilityService, others. A typed registry would be a useful follow-up.
• No PII redaction policy at this layer — callers are responsible for what they pass into properties.

Related

• ../announcements/ — captures announcement_published.
• ../payments/ — PaymentObservabilityService delegates here for PostHog calls.
• ../analytics/ — separate folder if it exists for client-side surfaces.

Source code

• API: apps/api/src/event-tracking/event-tracking.{service,module}.ts

Config