GA4 and Firebase Analytics share the same underlying Google infrastructure, which creates confusion about which one to use. In practice, they solve different needs, and the right answer depends on the type of product.
Same engine, different purposes
Firebase was built for mobile app product teams: technical events, crash reporting, remote config, native feature A/B testing. GA4 was built for marketing and combined web/app analytics teams: campaign attribution, conversion funnels, integration with Google Ads.
When to prioritize Firebase
If the product is a native app and the core questions are about in-product behavior (which feature gets used most, where the app crashes, which feature variant retains better), Firebase gives deeper, more native tools for that analysis, without going through a marketing analytics layer.
When to prioritize GA4
If the business needs to understand which marketing channel brings converting users, measure campaign ROI, or unify behavior across web and app in a single report, GA4 is the right tool, since it’s built on the same event model but focused on attribution and marketing.
The mistake of using both without a single event plan
It’s common to see implementations where Firebase and GA4 log events with different names and parameters for the same thing, creating two sources of truth that don’t match. Defining a single measurement plan, then deciding which events get sent to each tool, avoids that duplication.
The practical recommendation
For most products with app + web, the combination that works best is GA4 as the marketing and attribution layer, with Firebase (or its BigQuery export) as the deep product analysis layer, both fed by the same event plan.
If you have questions about what to implement for your product or how to integrate both tools, message me on WhatsApp.