Unveiling the best debugger: top iOS debugging apps and iPhone remote debugging tools

Introduction

Debugging iOS applications is a nuanced process fraught with unique challenges. Developers and QA engineers often contend with issues like limited access to device internals, sandbox restrictions, and the notorious difficulty of reproducing bugs that occur in real-world user environments. The complexity of the iOS ecosystem necessitates robust tools that can navigate these obstacles efficiently. Identifying the best debugger and mastering iPhone remote debugging are essential steps in delivering high-quality apps. In this review, we'll explore the top iOS debugging apps, examining their strengths and weaknesses to help you make informed decisions.

Challenges in iOS app debugging

• Limited device access: Apple's strict security policies restrict low-level access to device internals, making it harder to diagnose certain issues.
• Sandbox environment: Each app operates in its own sandbox, isolating it from other apps and system resources, which complicates inter-process communication debugging.
• Reproducing user issues: Bugs that occur under specific conditions or in particular user environments can be difficult to replicate without physical access to the device.
• Performance monitoring limitations: Gathering real-time data on CPU usage, memory consumption, and network activity requires specialized tools.
• Complex crash reports: Interpreting crash logs and stack traces can be challenging without adequate tools, especially when dealing with obfuscated code.

What kinds of debugging tools for iOS exist?

iOS debugging tools are indispensable assets in the development process, helping developers identify and fix coding errors at various stages of application creation.

These tools assist in analyzing code, understanding execution flow, and resolving issues to ensure smooth app performance on Apple's platforms. The ecosystem of iOS debugging tools includes a variety of applications and utilities designed to address different aspects of app development and testing. The main types of iOS debugging tools are:

• Integrated Development Environment (IDE) Debuggers: Tools like Xcode Debugger and LLDB, which are integrated into Xcode, provide features such as breakpoints, variable inspection, and step-through execution to debug apps within the development environment.
• Remote Debugging Tools: Solutions that allow developers to debug applications running on remote devices, facilitating the diagnosis of issues occurring in real-world user environments without physical access to the device.
• Network Monitoring Tools: Applications like Charles Proxy and Wireshark enable inspection of network traffic, helping developers debug API calls and network-related issues by capturing HTTP and HTTPS requests and responses.
• Crash Reporting Tools: Services such as Firebase Crashlytics, Instabug, and Sentry collect crash reports and analytics from deployed applications, providing insights into issues experienced by end-users and helping prioritize fixes.
• Performance Profiling Tools: Tools like Instruments in Xcode help analyze app performance, memory usage, CPU load, and energy consumption to optimize efficiency and identify bottlenecks.
• UI Debugging Tools: Utilities that allow developers to inspect and debug the user interface, including view hierarchy and layout constraints. Xcode's View Debugger and Reveal are popular choices.
• Logging and Analytics Tools: Libraries and services that facilitate logging within the app and collect analytics data to understand user behavior and app performance, such as Firebase Analytics.
• Automated Testing Tools: Frameworks like XCTest and Appium support automated testing, helping ensure app reliability and performance across different scenarios and devices.

Features of iOS Debugging Tools

iOS debugging tools offer a wide array of features designed to facilitate the development and maintenance of high-quality applications.

Let's explore some of the key features to better understand their capabilities:

1. Remote Debugging is a crucial feature in iOS debugging tools. It allows developers to connect to and debug applications running on remote devices, which is essential for replicating and resolving issues that occur in specific user environments. Tools like AppSpector provides this capability, enabling developers to inspect and modify the code, network activity, and user interface of their apps in real-time without physical access to the device.
2. Breakpoints and Watchpoints are fundamental features that let developers pause the execution of app code at specific points to analyze variable values, expressions, and memory in detail. These tools help identify logic errors, memory leaks, and data corruption. They can be set using IDEs like Xcode or debugging tools like LLDB.
   • Breakpoints: Set based on lines of code, allowing developers to halt execution at critical points to inspect the state of the application.
   • Watchpoints: Set based on variables or memory addresses, useful for monitoring changes and identifying unintended modifications.
3. Simulators and Emulators are vital software tools that replicate the behavior and environment of real iOS devices on a computer. They allow developers to test app functionality, compatibility, and responsiveness across various platforms, devices, and configurations without needing physical devices. Xcode comes with a built-in iOS Simulator that supports different device models and iOS versions.
4. Crash Reporting and Analytics tools gather and analyze data regarding app performance, errors, and user behavior. They assist in identifying errors, monitoring trends, and improving app quality and usability. These tools provide information like crash logs, stack traces, device details, user feedback, and usage statistics. Examples include Firebase Crashlytics, Instabug, and Sentry.
5. Logging and Tracing record and display messages, events, or data relevant to the app's execution. They help track and debug the flow, state, and output of the app's code, network, and UI. Features include filtering, searching, highlighting, or exporting logs and traces. Tools like Xcode's Console, CocoaLumberjack, and OSLog offer robust logging capabilities.
6. Performance Profiling tools analyze the app's performance in terms of CPU usage, memory consumption, network activity, and energy impact. Instruments in Xcode are a primary tool for this purpose, helping developers optimize their apps for better efficiency and responsiveness.
7. UI Inspection and Debugging tools allow developers to visualize and debug the app's user interface, including view hierarchies and layout constraints. Xcode's View Debugger and third-party tools like Reveal enable developers to inspect UI components, identify layout issues, and ensure a consistent user experience across different devices.
8. Network Traffic Inspection and analyzing network requests and responses is essential for debugging API interactions and network-related issues. Tools like Charles Proxy and Wireshark enable developers to view HTTP/HTTPS traffic between the app and the server, helping identify and resolve communication problems.
9. Automated Testing and Continuous Integration support for writing and running automated tests help ensure code changes do not introduce new bugs. Frameworks like XCTest allow developers to create unit tests, UI tests, and performance tests. Integration with continuous integration systems like Jenkins or GitHub Actions automates the testing process.
10. Security Analysis tools help identify and fix vulnerabilities within the app, ensuring data protection and compliance with privacy regulations. Tools like iOS Security Suite and MobSF (Mobile Security Framework) assist in performing security assessments.

By leveraging these features, iOS developers can efficiently identify and resolve issues, optimize app performance, and deliver a high-quality user experience. The right combination of tools enhances productivity and helps overcome the inherent challenges of iOS app development.

Top 10 iOS debugging apps

When it comes to finding the best debugger for iOS development, several tools stand out for their ability to simplify and enhance the debugging process.

Below is a curated list of the top iOS debugging apps, each with its own set of features, pros, and cons to help you choose the right tool for your needs, including options for iPhone remote debugging.

1. Xcode Debugger

Description: Xcode Debugger is part of Apple's official Integrated Development Environment (IDE) for macOS, providing comprehensive tools for developing and debugging iOS applications.

Pros:

- Deep integration with the development environment.

- Supports breakpoints, step execution, and variable inspection.

- Visualizes UI elements and offers view hierarchy debugging.

- Provides memory and CPU usage profiling.

Cons:

- Limited to local debugging; cannot perform effective iOS remote debugging without physical device connection.

- Steep learning curve due to the complexity of features.

- Wireless debugging can be unstable and slower compared to wired connections.

2. LLDB (Low-Level Debugger)

Description: LLDB is a high-performance, command-line debugger that's part of the LLVM project and integrated into Xcode.

Pros:

- Powerful for low-level debugging tasks.

- Supports advanced features like watchpoints and thread debugging.

- Excellent for inspecting application state at a granular level.

- Requires proficiency with command-line interfaces.

Cons:

- Not beginner-friendly.

- Has a steep learning curve.

- No built-in support for remote debugging without additional setup.

3. Charles Proxy

Description: Charles Proxy is an HTTP proxy and monitoring tool that allows developers to view all HTTP and HTTPS traffic between their devices and the Internet.

Pros:

- Decrypts SSL traffic to inspect HTTPS requests and responses.

- Useful for debugging network calls and API interactions.

- User-friendly interface and cross-platform support.

- Requires manual proxy configuration on the device.

Cons:

- Not specifically designed for remote; best used during development.

- Can introduce latency, affecting app performance during debugging sessions.

4. TestFlight

Description: TestFlight is Apple's online service for over-the-air installation and testing of mobile applications.

Pros:

- Facilitates beta testing with real users on actual devices.

- Simplifies distribution of test builds.

- Collects basic crash reports and user feedback.

Cons:

- Limited debugging capabilities; mainly a distribution tool.

- Crash reports are less detailed compared to specialized tools.

- Does not support real-time debugging or in-depth inspection.

5. Bugsee

Description: Bugsee captures video of user interactions, network traffic, and system logs when a bug or crash occurs.

Pros:

- Provides context by recording events leading up to a crash.

- Captures console logs, network traffic, and device details.

- Easy integration with various bug-tracking systems.

Cons:

- Potential privacy concerns due to recording user sessions.

- Continuous monitoring may impact app performance.

- Lacks interactive debugging capabilities for immediate issue resolution.

6. Instruments

Description: Instruments is a performance analysis and testing tool integrated into Xcode.

Pros:

- Offers detailed profiling of CPU, memory, disk, and network usage.

- Visualizes performance data over time.

- Helps identify memory leaks and performance bottlenecks.

Cons:

- Complex interface that can be overwhelming for new users.

- Not designed for traditional debugging like code stepping.

- Requires tethered device connection.

7. CocoaLumberjack

Description: CocoaLumberjack is a fast, simple, and versatile logging framework for macOS and iOS.

Pros:

- Provides extensive logging capabilities with different log levels.

- High-performance and efficient, suitable for production environments.

- Easy to integrate and configure.

Cons:

- Logging only; does not offer interactive debugging features.

- Requires manual setup to collect and analyze logs remotely.

8. Reveal

Description: Reveal is a powerful runtime view debugging tool for iOS developers, allowing inspection and modification of views in real-time.

Pros:

- Visualizes view hierarchies and layout constraints.

- Enables real-time editing of UI elements.

- Helps identify and fix UI issues quickly.

Cons:

- Commercial software with a licensing fee.

- Requires integration into the app, which may not be feasible for all projects.

- Focused on UI debugging; does not cover code-level debugging or iOS remote debugging.

9. Firebase Crashlytics

Description: Firebase Crashlytics is a real-time crash reporter that helps track, prioritize, and fix stability issues in your app.

Pros:

- Real-time crash reporting with detailed stack traces.

- Helps identify the cause of crashes and prioritize fixes.

- Integrates well with other Firebase services.

Cons:

- Focused solely on crash reporting; lacks interactive debugging features.

- Does not support real-time iPhone remote debugging.

- May require additional setup for advanced features.

10. Instabug

Description: Instabug provides in-app feedback, bug reporting, and crash reporting for mobile applications.

Pros:

- Easy in-app bug reporting with annotated screenshots and screen recordings.

- Real-time crash reporting with detailed logs and user steps.

- Offers user feedback mechanisms for direct insights.

Cons:

- Potential privacy concerns due to user data collection.

- Additional SDK integration may increase app size.

- Primarily a bug reporting tool; lacks capabilities for interactive iPhone remote debugging.

By evaluating these top iOS debugging apps, developers can choose the best debugger that fits their specific needs.

While each tool has its strengths, they often have limitations when it comes to comprehensive debugging.

AppSpector: a companion for solving tricky issues

While the tools listed above provide valuable features, they may not fully address the challenges of remote debugging and real-time monitoring in complex, real-world environments.

AppSpector emerges as a powerful companion to these tools, enhancing your debugging capabilities by offering:

Remote debugging capability: Enables real-time iPhone remote debugging without physical device access.

Comprehensive monitoring: Provides live data on network requests, database operations, and UI rendering.

Two-way communication: Allows you to execute commands and interact with the app remotely.

Easy integration: Simple SDK setup that doesn't disrupt your existing workflow.

AppSpector doesn't aim to replace your existing tools but complements them, filling in the gaps where traditional debuggers fall short.

It excels in solving tricky issues that are hard to reproduce and require observation in a live environment, making it an invaluable addition to your development arsenal.

AppSpector monitors

AppSpector offers a comprehensive suite of monitors that provide deep insights into your application's behavior, enabling efficient debugging and performance optimization. Here are some of the most useful monitors:

Performance Monitor

The Performance Monitor is essential for developers who understand the critical importance of performance metrics in app development. It provides real-time data on CPU and memory load, network traffic, disk writes, and battery usage, all presented in easy-to-understand charts. By using the Performance Monitor, you can quickly identify bottlenecks in your code before they impact your users, ensuring your app runs smoothly and efficiently.

Network Monitor

The Network Monitor is a critical tool for any modern app that relies on backend services. It allows you to monitor all HTTP traffic in your app in real-time. You can examine any request, view request and response headers and bodies, and highlight XML and JSON responses with formatting and folding options.

Even for large responses, it's easy to navigate and analyze the data.

The Network Monitor also lets you view request status codes, sort and filter requests, and quickly find specific requests with a powerful search function.

Think of it as a remote, real-time Charles Proxy. You can also share or save problematic requests by exporting them to cURL or HAR, streamlining your app development process.

Logs Monitor

The Logs Monitor displays all the logs generated by your app. It allows you to see everything you print to stdout within seconds, with capabilities to filter, search, and save your logs.

AppSpector's SDK seamlessly integrates with popular logging frameworks like CocoaLumberjack, ensuring all your logs are displayed with respect to their logging levels. It also offers an SDK-level logger and sanitizing utilities to filter sensitive user data and highlight important information.

With the Logs Monitor, you'll never miss a critical log message again, streamlining your logging process and giving you the insights you need for optimal app performance.

Analytics Monitor

Tracking every user interaction is crucial for effective product marketing, and the Analytics Monitor ensures you never miss an analytics event. With AppSpector, you can see all analytics events in real-time, without waiting for services like Google Analytics to update their views.

You can check initialization parameters, all sent events, and their attributes, ensuring that you've sent everything needed. If there's a problem, you can be confident it's not on your side. The Analytics Monitor provides the insights you need to make informed decisions and optimize your product marketing strategy.

Commands Monitor

The Commands Monitor complements AppSpector's other monitors by providing even more control over your app. It allows you to send predefined actions from the dashboard back to your app, giving you true freedom for debugging and introspection of your code.

You can build custom data structures and send them to your app at any time, handle them on the app side, and send back a response—successful or failed. All commands are stored in history and are available for re-run, providing a true two-way connection with your app. With the Commands Monitor, you can, for example, pass stubs for API responses at runtime and see how your app behaves, extending your debugging capabilities even further.

Custom Events Monitor

The Custom Events Monitor provides ultimate freedom and flexibility in monitoring your app's performance. It allows you to define a custom event structure and add the fields you want to pass to the AppSpector frontend, giving you complete control over what you monitor and how.

You can send your custom events at any point in your app's lifecycle and see the results in real-time on our web dashboard.

All events are stored in history and are available for ended sessions as well. This monitor provides an additional abstraction layer, offering a context where you can gather any info you need—errors, requests, user actions, environment changes, and more.

Environment Monitor

The Environment Monitor gathers all your environment variables and arguments in one place, including info.plist, CLI arguments, OS info, and much more. As a developer, you know that the environment in which your app runs can have a significant impact on its behavior. With the Environment Monitor, you can easily pinpoint any issues that arise due to environmental factors and streamline your app development process.

FileSystem (FS) Monitor

The FileSystem Monitor provides a powerful remote file manager for your app. It allows you to navigate your app's file structure, including the app bundle itself. Whether you're checking if temporary files were created or need to download an SQLite file to load into a database viewer, the FS Monitor has you covered.

You have read/write access wherever possible, so you can not only examine files but also upload or create new files within your app's sandbox container. This gives you greater control over your app's file management and helps streamline your development process.

CoreData Monitor

The CoreData Monitor unlocks the full potential of your Core Data usage. It provides a complete solution for working with Core Data, including features that make data management more intuitive.

You can view the model schema just like in Xcode's editor, navigate your data, follow relationships, and examine store and entity properties. There's no need to struggle with contexts and threading—you can switch contexts easily and view even unsaved data.

You can run custom fetch requests against any model or context and get results instantly. The monitor updates all errors in real-time and supports iCloud stores, making it an indispensable tool for any iOS developer working with Core Data.

Location Monitor

The Location Monitor streamlines the testing of location-based features in your app. Instead of physically moving to test your location code, you can simply point to a location on the map, and the monitor will inject into the Apple SDK to mock the location information completely for the whole app, including third-party SDKs and Apple Maps. This saves you time and ensures your app's location-based features are working as expected without the need for manual testing in different geographic locations.

Notification Center Monitor

The Notification Center Monitor offers a convenient way to track all posted notifications and notification subscriptions in your app.

You can examine notification user info, sender/receiver objects, and other important details. Additionally, you can post notifications to your app remotely from the frontend, eliminating the need to write debug code to test if notifications are working properly. This monitor enhances your ability to debug and test notification-related features efficiently.

Screenshots Monitor

The Screenshots Monitor provides a simple and useful way to capture screenshots from your device in real-time. You can take screenshots yourself without relying on your QA team, and save them for future reference. This feature is especially helpful for documenting app states during testing and debugging, ensuring that you have visual records of your app's behavior at various stages.

SQLite Monitor

The SQLite Monitor is a powerful tool for browsing and tracking SQLite databases in your app. It automatically finds database files and connects to them, allowing you to track all queries and view your database schema and data. You can issue custom SQL queries on any database and see the results immediately in the browser. All queries are tracked and measured in real-time, and you can easily switch between databases and view their schemas with just a few clicks.

The monitor supports views and triggers, making it a comprehensive solution for working with SQLite databases and ensuring data integrity.

User Defaults Monitor

The User Defaults Monitor provides a dedicated tool for examining all data stored in NSUserDefaults in real time. It's invaluable for storing app metadata, environment state, and more.

The monitor supports native data types and offers a handy UI for collections, as well as editing capabilities. Need to switch to another boolean flag to test your app's behavior? With AppSpector, you can do it remotely without needing to recompile the app. This monitor streamlines your development process by allowing you to modify settings on the fly.