Performance monitoring is a service we offer that helps us to gain insight into the performance characteristics of your app. Key capabilities We use performance monitoring to collect performance data from your app, and then review and analyze that data. Performance monitoring helps us understand where and when the performance of your app can be improved so that we can use that information to fix performance issues. Automatically measure app startup time, HTTPS network requests, and more As soon as your app goes live it starts automatically monitoring several critical aspects of performance. We log aspects like first contentful paint, ability for users to interact with your app, and more. Gain insight into situations where app performance could be improved Optimizing the performance of your app can be challenging when you don’t know exactly why it is falling short of user expectations. That’s why our performance monitoring lets you see performance metrics broken down by attributes, like country, device, app version, and OS level. Customize monitoring for your app In certain situations we can create custom traces to capture your app’s performance in specific situations, like when your users load a new screen or display a new interactive feature. And, we can create custom metrics to count events that we define (like cache hits) during those traces. User data Your app’s performance monitoring does not permanently store any personally identifiable information (such as names, email addresses, or phone numbers). While monitoring HTTPS network requests, Performance Monitoring uses URLs (not including URL parameters) to build aggregated and anonymous URL patterns that are eventually persisted and shown in the Firebase console.