Firebase / Google Analytics 4

Your players: new players by first-open day, where they came from (first-user source and medium) and country; how far they get in your funnel; whether they come back; and the ad and purchase revenue each first-open cohort has earned so far. This is the source that ties spend to players, so set it up first.

"ga4": { "enabled": true, "properties": ["123456789"], "auth": "service-account" }

Access

Service account (recommended): use the same key as for Google Ads (google-ads.md), enable the Google Analytics Data API in that Cloud project, and in GA4 open Admin → Property access management → + and add the service account’s email as Viewer.

Your own login: set "auth": "oauth" and run earnback connect google (see admob.md).

Funnel

The funnel in the config lists the events that make up your funnel, in order. first_open (logged by Firebase automatically) marks a new player and must come first. Add the events your game logs:

"funnel": [
  { "event": "first_open", "label": "Opened" },
  { "event": "tutorial_begin", "label": "Started tutorial" },
  { "event": "tutorial_complete", "label": "Finished tutorial" },
  { "event": "level_up", "label": "Reached level 2" }
]

A step counts players of a first-open day who logged that event at any time since, so the numbers of recent days still grow.

Channels

Players are credited to the channel of their first-user source / medium in GA4. The defaults:

Add your own rules under channels in the config; they are checked first. source and medium are case-insensitive regular expressions matched against the whole value:

"channels": [{ "source": "partner-network", "medium": "referral", "channel": "partner" }]

Revenue

• Ad revenue per cohort needs AdMob’s impression-level ad revenue in Firebase: link each AdMob app to its Firebase project and turn on impression-level ad revenue in AdMob’s settings. Firebase then logs an ad_impression event with its value, and GA4’s totalAdRevenue can be split by the player’s first-open day and source, which is what payback curves are built from.
• Purchase revenue comes from GA4’s purchaseRevenue (Firebase logs Play and App Store purchases with in_app_purchase).

Without impression-level ad revenue, use the AdMob connector for totals; payback per channel then counts purchases only.

Caveats

• Players who don’t allow analytics (consent declined, EEA consent mode) are missing, so cost per player for one channel is an upper bound.
• GA4 needs about two days to settle. Earnback re-reads the last 35 days and marks data complete up to two days ago.
• GA4 withholds small numbers when Google Signals is on (data thresholds). If the report says so, switch Admin → Reporting identity to Device-based.
• (direct) / (none) is common for store installs whose referrer Google didn’t pass on. It lands in Unknown, in plain view.

Errors