What are the best ways to debug a slow or unresponsive mobile application?

Use Profiling Tools (Android Profiler, Instruments), integrate Firebase Performance Monitoring for real-time insights. Analyze network with Charles Proxy, optimize requests. Memory profiling tools for leaks, UI profiling for rendering bottlenecks. Code profiling (CPU Profiler, Time Profiler), monitor battery usage, test on various devices, analyze app size with APK Analyzer, implement detailed logging and analytics, set up benchmarks (JUnit, XCTest), gather user feedback and crash reports, regular code reviews, implement caching, use asynchronous operations for tasks, test under various conditions, ensure compatibility with the latest SDKs and OS versions and simulate heavy loads for performance stress testing.

Use tools like Android Profiler and Instruments, and integrate Firebase. Utilize Charles Proxy to analyze and optimize network requests. Employ memory profiling tools to identify leaks and address UI rendering bottlenecks. Conduct code profiling using CPU Profiler and Time Profiler, monitor battery usage, and test on diverse devices. Analyze app size with APK Analyzer, implement detailed logging and analytics, establish benchmarks using JUnit and XCTest, gather user feedback and crash reports. Conduct regular code reviews, implement caching, employ asynchronous operations, test under various conditions, ensure compatibility with the latest SDKs and OS versions, and simulate heavy loads for performance stress testing.

Performance Profiling: Use mobile application profiling tools like Android Profiler or Instruments (for iOS) to identify performance bottlenecks and resource usage. Network Monitoring: Check for slow or blocked network requests using tools like Chrome DevTools (for WebView-based apps) or native network monitoring tools on the respective platforms. Memory Management: Analyze memory usage and identify memory leaks with tools like Xcode's Instruments (for iOS) or Android Studio's Memory Profiler to ensure efficient memory management in your mobile application.

In certain instances, the API might return a substantial amount of data. To address this, we can enhance the API's efficiency by incorporating pagination into the list

While optimising code, prioritize offloading less important tasks for later in a non-blocking way. Avoid task overload at startup, as an unresponsive app right at the start is much worse than later somewhere.

In my experience, the most common cause of unresponsive UI is performing I/O work on the UI thread. For Android, investigate if your function calls to SharedPreferences, SQLite databases, and any file operations are not running on the UI thread. Kotlin's inbuilt support for coroutines and flows comes in handy here.

To Enhance app performance mostly you need to work on App startup time, Slow rendering (jank), Smooth Screen transitions, Long running work. Android Studio provides profiling tools like CPU profiler, Memory profiler and Energy profiler are helpful to find these problems. The Jetpack Microbenchmark library help to inspect and monitor the performance of your app such as startup, interacting with the UI, and animations.

To effectively monitor a mobile application's behavior, employ tools that provide real-time insights into events, metrics, and user feedback. In an iOS development environment, Xcode Organizer serves as a central hub for managing crashes and performance data. App Store Connect Analytics complements these tools by providing additional insights into app usage and user engagement.

Not only keep your dependencies of your App up-to-date, but rather minimize the amount of dependencies you need to have. Because to many dependencies can be cause of unexpected behavior like low performence or other issues.

Always check the changelog to ensure issues from previous versions are fixed. Don't rush to implement updates, especially those with new features, can introduce new issues. Even alpha, beta, and nightly releases may not cover all potential issues or edge cases.