What is an App Event?
An app event is a tracked user action inside a mobile app or SPA (single-page app). It’s the atomic unit of behavioral data: each event has a name and optional parameters (key–value pairs). In event-based analytics, everything—install, screen view, purchase, even errors—is an event.
How do app events work?
SDKs send event payloads from the client (or server) with a timestamp, user/device identifiers (e.g., a hashed ID), and parameters. Tools like GA4, Matomo, Plausible, Simple Analytics, Mixpanel, or Snowplow store these and compute metrics such as engagement rate, conversion rate, and LTV (lifetime value). Unlike a web-only model centered on the pageview, app analytics treats the event as the source of truth—sessions are derived, not primary. See also session.
Why it matters
App events power funnels, cohorts, and attribution. They let you answer: Which features drive retention? What parameters correlate with a conversion? Which campaign produced value after install (see UTM and attribution model)? Events also enable streamed analysis in warehouses (e.g., BigQuery) and via APIs (Measurement Protocol).
Naming & implementation tips
- Use a clear schema: lowercase, snake_case names (
add_to_cart,purchase). - Keep parameters consistent (e.g.,
value,currency,item_id). - Mark the few events that define business success as conversions (not everything).
- QA in staging and monitor in real-time data to catch missing params.
- Route through a tag management layer or server endpoint when possible for stability.
Common examples
| Event name | Typical parameters | Purpose |
|---|---|---|
first_open | source, campaign | Install attribution & onboarding health |
screen_view | screen_name, screen_class | Navigation & user flow |
add_to_cart | item_id, value, currency | Micro-step toward a goal |
purchase | transaction_id, value, currency | Revenue tracking & ROI (attribution) |
Pitfalls to avoid
Over-logging (noise), redefining event names mid-flight, inconsistent currency handling, and missing identifiers. Keep a schema doc, version it, and deprecate safely.
Related terms: Event, Conversion, Session, Screen View, Pageview, Attribution Model, UTM