What needs to be implemented to capture interactions from a mobile app in Google Analytics 4?

To capture interactions from a mobile app in Google Analytics 4, it is essential to implement the Firebase SDK. The Firebase SDK is specifically designed to enable developers to collect analytics data from mobile applications seamlessly. This SDK provides a range of features, including automatic event tracking and user engagement metrics, which are vital for understanding user behavior within mobile apps.

By integrating the Firebase SDK, developers can track various user interactions and events that occur within the app, allowing for in-depth analysis of user engagement and conversion pathways. This data is then transmitted to Google Analytics 4 for reporting and insights, helping businesses optimize their app and improve user experience.

In contrast, using JavaScript tracking code is suitable for web environments, while HTML5 tracking tags also pertain primarily to web applications and would not be effective in capturing mobile app interactions. Mobile web optimization focuses on enhancing the performance and usability of websites on mobile devices, which does not directly facilitate the tracking of app-specific interactions. Hence, the Firebase SDK is the definitive solution for this requirement.