Firebase analytics

Firebase Analytics

Minimum viable example

import analytics from "@react-native-firebase/analytics";

await analytics().logEvent("post_created", { category: "blog", word_count: 450 });
await analytics().setUserProperty("tier", "pro");

Event names: lowercase_snake_case, ≤ 40 chars, ≤ 25 params per event. Violations are silently dropped — verify with DebugView before shipping.

1. Install

Web

npm install firebase

import { getAnalytics, isSupported } from "firebase/analytics";

let analytics: ReturnType<typeof getAnalytics> | null = null;
isSupported().then((ok) => {
  if (ok) analytics = getAnalytics(app);
});

isSupported() is required for SSR (Next.js) — getAnalytics throws in non-browser environments.

Expo / React Native

npx expo install @react-native-firebase/analytics

Add to app.json:

{
  "expo": {
    "plugins": ["@react-native-firebase/app", "@react-native-firebase/analytics"]
  }
}

Rebuild (npx expo prebuild --clean + EAS Build).

2. iOS App Tracking Transparency (ATT)

For any IDFA-based analytics (cross-app tracking, ad attribution), iOS 14.5+ requires explicit user consent via the ATT prompt. Without it, IDFA is zeroed out and ad measurement breaks.

npx expo install expo-tracking-transparency

app.json:

{
  "expo": {
    "ios": {
      "infoPlist": {
        "NSUserTrackingUsageDescription": "We use this to measure ad performance and personalize content."
      }
    }
  }
}

import { requestTrackingPermissionsAsync } from "expo-tracking-transparency";

const { status } = await requestTrackingPermissionsAsync();
// status is "granted" | "denied" | "restricted" | "undetermined"

Firebase Analytics still works without ATT for first-party events and aggregate metrics — only IDFA-linked features (Audiences for ads, attribution) are affected.

If shipping in the EEA, UK, or Switzerland, you also need Google Consent Mode v2 — see references/consent-mode.md. Without it, Google blocks all data from those regions.

3. Log events

import analytics from "@react-native-firebase/analytics";

await analytics().logEvent("post_created", {
  category: "blog",
  word_count: 450,
});

Reserved events (screen_view, login, sign_up, purchase, search, etc.) get richer reporting — use them when applicable:

await analytics().logLogin({ method: "google" });
await analytics().logSignUp({ method: "email" });
await analytics().logPurchase({
  currency: "USD",
  value: 9.99,
  items: [{ item_id: "pro_monthly", item_name: "Pro Monthly", price: 9.99 }],
});

Event naming rules

• Lowercase snake_case
• ≤ 40 characters
• ≤ 25 parameters per event
• Parameter names ≤ 40 chars, values ≤ 100 chars (string) or number

Events that violate these rules are silently dropped. Test in DebugView (next section).

4. Real-time debugging (DebugView)

The Analytics dashboard has a 24h delay. For development, use DebugView for real-time event verification:

# iOS Simulator
xcrun simctl spawn booted log stream --predicate 'subsystem == "com.google.firebase.analytics"'

# Or enable persistently:
adb shell setprop debug.firebase.analytics.app <your.package.name>

For iOS, in Xcode → Edit Scheme → Run → Arguments → add -FIRDebugEnabled to "Arguments Passed On Launch".

Open Firebase Console → Analytics → DebugView → your device appears, events stream in seconds.

5. User properties and IDs

await analytics().setUserId(user.uid);
await analytics().setUserProperty("tier", "pro");
await analytics().setUserProperty("signup_source", "google");

User properties are usable as Audiences for Remote Config targeting and Firebase Messaging campaigns. They're also dimensions in BigQuery exports.

Privacy: never set personally identifiable strings as user properties (email, name, phone). Use anonymous IDs only. The userId accepts an opaque string — your Firebase Auth uid is fine.

6. Screen tracking (React Navigation)

import analytics from "@react-native-firebase/analytics";
import { useRef } from "react";
import { NavigationContainer } from "@react-navigation/native";

const navigationRef = useRef<NavigationContainerRef<any>>(null);
const routeNameRef = useRef<string>();

<NavigationContainer
  ref={navigationRef}
  onReady={() => { routeNameRef.current = navigationRef.current?.getCurrentRoute()?.name; }}
  onStateChange={async () => {
    const previous = routeNameRef.current;
    const current = navigationRef.current?.getCurrentRoute()?.name;
    if (previous !== current) {
      await analytics().logScreenView({ screen_name: current, screen_class: current });
    }
    routeNameRef.current = current;
  }}
>

For Expo Router, hook into the useSegments() change instead.

7. BigQuery export

For raw event analysis beyond what the console offers, enable BigQuery export:

Firebase Console → Project Settings → Integrations → BigQuery → Link.

Events stream to a daily-partitioned table (events_YYYYMMDD) with ~1 hour delay. Pricing: free under 1M events/day; standard BigQuery beyond.

8. Common mistakes

• Calling getAnalytics in Next.js without isSupported. Throws during SSR.
• Expecting events in the dashboard immediately. 24h delay. Use DebugView for verification.
• Naming events in CamelCase or with spaces. Silently rejected.
• Setting PII as user properties. Violates Google's terms and risks account suspension.
• Forgetting to rebuild after adding the plugin. @react-native-firebase/analytics requires native code.
• Treating Analytics as a real-time event bus. It's batched. For real-time, write events to Firestore or Pub/Sub.