How to Integrate Firebase With GA4 Without Losing Valuable Data

Working as a Senior Data Specialist, I’ve come across a series of common mistakes that prevent enterprises from leveraging this tool to its full potential—and consequently, accessing the true value of their data. During a series of panels at Melbourne MeasureCamp, I was lucky enough to host a session on these observations and some recommendations so that brands can bank on actionable insights into user behavior and application performance. If you missed it, continue reading for the main takeaways.

Learning #1: Only one Firebase project can be linked to one GA4 property.

An important thing to consider when it comes to integrating Firebase with GA4 is that only one Firebase project can be linked to one GA4 property. This means that if there are multiple Firebase projects, it’s necessary to transfer all applications—regardless of operating systems or development cycles—into one project and link it to the main GA4 property. 

This requires careful planning and a deep understanding of how Firebase projects are set up.  Keep in mind the potential technical challenges and limitations in migrating apps from one project to another. For example, certain app developers may have their own preferences in terms of project setups, so you need to talk to your development team and understand what that looks like. 

Also, be aware of dependencies such as Crashlytics or BigQuery exports setup when moving apps from one project to another. Each Firebase project can have multiple stack integrations, and we should be ready to reconfigure all of them. Make sure you have historical data and map out timelines for these app migrations.

Learning #2: Standard naming unlocks customer insights. 

The main reason why you’d want to integrate Firebase with GA4 is that it provides valuable insights about user journeys across web and app platforms. However, the only way to unlock those insights is by ensuring standard naming conventions for web and app events. 

First, you’ll need to create a Google Sheet or an Excel spreadsheet to standardize the naming of events and parameters. Here’s an example:

As you can see, we recommend having standardized event names and parameters across web and app platforms in GA4. It may seem simple, but it's not uncommon for organizations to use different conventions on different platforms, making it harder to cross-reference the data.  

Other tips to make the process easier include:

• If you have a website, but no app implementation yet, rely on your web and GA4 Recommended Events to name the event and implement these for the app.
• If you already have an app implemented with Firebase, use the mapping sheet to understand which events from the app can be mapped to web. It is easier to rename web events with GTM than doing so for the app.
• Align with both web and app development teams for naming conventions. For example, using camelcase (e.g. SignUp) vs snake case (sign_up)

Learning #3: Be Aware of Data Collection Limits.

When you use Firebase to collect data from your apps, it’s important to be mindful of the data collection and configuration limits. Firebase Analytics does not log events, event parameters, and user properties that exceed certain limits—which means that the platform will drop the events and stop tracking valuable data even if you exceed the limit by a few characters. 

In my experience, this mistake is especially common among developers who implement the Firebase SDK without really knowing about the limits. These are some of the main caveats and my respective recommendations for them:

• Event parameters limits: 25 parameters per event may seem a lot, but it may add up if you’re sending ecommerce events. GA4 and Firebase will drop the events and event parameters if you exceed this limit.
• Be careful not to go over the maximum length of the event parameter value, which currently stands at 100 characters. Be aware of user-generated values (e.g. listing name in marketplaces)
• Remember that Firebase does not accept array type parameters.
• When setting up BigQuery export for GA4 (with both app and web streams), check the usage in advance so that you don’t get shocked with the cost for the storage and querying the data. Pro tip: Set up daily aggregated tables for important metrics instead of querying directly from raw export tables.

In conclusion, it is essential to be aware of limitations around linking Firebase projects with GA4 property and plan ahead for your migration. Create a mapping sheet to map the events across the website and apps and standardize app and web events naming. Take note of Firebase data collection limits and make sure you are not going over the limits and risk losing your data. Finally, learn how to debug apps using Firebase Debug Mode, a bonus tip that can save you time and headaches.