How to Implement Effective Error Handling and Crash Reporting in Your Mobile App

When apps crash, users quickly lose patience. A sudden app failure interrupts their workflow, erases unsaved progress, or causes them to miss out on content. These negative experiences lead to frustration, which is reflected in online reviews and ratings. For app developers, crashes directly translate to unhappy customers, negative brand perception, and reduced revenue.  

In fact, a study found that nearly 37% of users stop using an app after severe issues, such as crashes. With mobile app markets being extremely competitive, developers simply cannot afford to let crashes continually plague their apps. Proactive stability management is critical.

The Promise of Proactive Prevention

Thankfully, app crashes are highly preventable through robust error handling and stability monitoring using crash reporting tools. 

Error handling involves gracefully catching errors, providing context for users, and recovering to keep the app running smoothly. Crash reporting gives developers visibility into real-world crashes, along with the insights needed to fix reoccurring issues.

Together, these capabilities allow developers to find and address problems before they have a widespread impact. Issues can be prioritized based on severity and frequency and then patched rapidly. Over time, apps become more resilient.

Why This Matters to Your Business 

For app-based businesses, investing in stability pays dividends over the long run. Apps with crash rates of just 1-2% tend to have vastly higher user retention and better reviews. With the cost of acquiring new customers being 5-25x higher than retaining them, there is a clear financial incentive to focus on error handling early on.

Overall, proactively optimizing stability saves money and protects your reputation with users. It should be a priority for any quality-focused mobile team.

What Are Errors?

Errors refer to problems that disrupt the normal flow of app execution. On a technical level, they manifest as exceptions that the code isn’t equipped to handle by default. Common error types include:

• Runtime errors: Thrown when issues occur during execution, like invalid operations, IO problems, access violations, and more. 
• Logical errors – Flaws in program logic that cause unintended behavior. Hard to detect.
• Resource errors: Lack of system resources like memory, storage, and network connectivity.
• User errors: Invalid inputs from users outside expected parameters. 

Why Errors Happen 

Errors generally stem from unanticipated edge cases, system-level problems out of the app’s control, or incorrect assumptions in business logic. Specific triggers include:

• Poor network connectivity causing failed API calls
• Buggy device drivers or firmware versions 
• Users entering invalid data into input forms
• Memory limitations on mobile devices
• Race conditions from asynchronous code
• Improper exception handling, allowing cascade failures

The Importance of Graceful Handling

Instead of showing users ugly stack traces, well-structured error handling provides clear visibility into issues while allowing the app to recover. Key capabilities include:

• Preventing crashes through catch blocks and contingency code paths
• Translating error codes into user-friendly messages 
• Allowing users to correct problems with contextual guidance
• Logging details to help developers investigate and debug
• Enabling temporary solutions like showing cached data

Implementing Error Handling in Mobile Apps

While error-handling concepts are universal, the implementation varies across platforms. 

On iOS, developers can leverage try-catch blocks to catch and handle exceptions. For custom errors, Apple recommends creating NSError objects with domain, code, and userInfo properties. These get passed through the chain of method calls via delegates. iOS apps can also define custom exception types when needed.

For Android apps, try-catch blocks form the core of exception handling. Developers can extend the Exception class to create custom exceptions that add more context. Another option is implementing the UncaughtExceptionHandler interface to catch unhandled exceptions globally and perform actions like logging before the app crashes. 

Common Strategies

In addition to platform-specific syntax, certain error-handling strategies work extremely well across mobile apps:

Input Validation

Check all incoming data from forms, APIs, and files against expected types, formats, ranges, and business rules. Validate as early as possible, like when data enters the app.

Defensive Programming

Add explicit checks before executing major components like network calls, database operations, and OS integrations. Check for null values, valid states, permissions–anything that could go wrong. 

Retry Mechanisms

For transient failures like network blips or timed-out operations, automatically retry the operation 2-3 times before treating it as a failure. Exponential backoff is a good strategy.

Fallback Options

Prepare contingency solutions upfront for when portions of the app fail. For example, showing cached data when the API is unreachable. Make degradations graceful.

Leveraging these patterns helps apps anticipate issues and handle them elegantly to maintain continuity of service.

Why Crash Reports Are Crucial

While error handling aims to prevent crashes, even the most robust apps suffer the occasional failure in production. Crash reporting gives insight into these real-world crashes – invaluable data for developers to address issues affecting users. 

Reports contain full stack traces plus contextual device data like OS version, memory state, and repro steps. Aggregated anonymously, they help identify crash trends and high-impact problems. Teams can then prioritize fixes based on frequency and severity. Over time, apps become far more stable through ongoing crash insights.

Crash Reporting Tools

Popular cross-platform crash reporting tools include:

Firebase Crashlytics

Provides real-time crash alerts, grouping and metrics in the Google Firebase console. Integrates tightly with other Firebase services for attribution and segmentation. Offers deobfuscation for mapping production crashes to your original source.

Sentry 

Features customizable event grouping, user tracking to recreate crashes, release health metrics, and advanced integrations. Has its own triage workflow for collaboration. Supports all major platforms.  

Bugsnag

Allows tracking error rates over time, alerting for new issues, user demographics per crash, and integration with communication tools like Slack and Jira. Provides codeless crash symbolication.

Beyond the Basics: Advanced Error Handling

A/B Testing Error Handling

Sophisticated mobile teams use A/B testing to experiment with different error-handling flows. For example, testing error message copy, recovery options, fallback behaviors, and more. This provides data on how changes impact key metrics like crash rates, conversions, and retention. Teams can iterate to optimize stability and user experience.

Advanced Monitoring 

Sentry, Bugsnag, and other tools allow tracking of overall error rates and trends at the code level. Teams can slice and dice by device, OS, and geography to identify high-error user segments. Funnel and cohort analysis shows how errors relate to user behavior over time. These insights guide engineering priorities and product improvements.

Custom Error Reporting

For additional flexibility, apps can route errors to internally-managed monitoring systems. This allows complete control over data management, routing logic and tool integrations. Requires more effort to build and maintain. Useful for complex setups or regulatory compliance needs.

Proactive Prevention

Static analysis tools like SonarQube and Lint can automatically scan code for hidden crash risks like null pointers, race conditions and memory leaks. This allows developers to address many failure scenarios proactively during development, before users are ever impacted. Proactive analysis complements runtime crash reporting.

Together these practices enable highly mature error handling for critical applications like banking, healthcare, and transportation.

Analyzing and Utilizing Crash Reports

The key to stability improvements lies in effectively analyzing crash report data and collaborating cross-functionally to address underlying issues. Best practices include:

Prioritizing Crash Fixes 

Leverage crash grouping to understand the breadth of impact for each issue. Combine with frequency data and business impact analysis to objectively prioritize engineering efforts on fixes that improve experience for the largest user segments.

Identifying Trends

Slice crash data along different dimensions like device type, OS version, geo, etc. Identify if crashes concentrate in particular user segments. Track trends over time to gauge if crashes are increasing or decreasing.

Collaborating on Resolutions

Share crash details and trends with product managers, engineers, and QA teams. Brainstorm potential reasons and solutions. Capture repro steps and other actionable data to accelerate fixes. Consider adding user experience tweaks to complement engineering fixes. 

Monitoring Stability 

Continuously track crash rates, affected users, and quality metrics pre and post-fixes to confirm stability improvements over time. Measure results across builds to quantify the ROI of reliability investments. Expand monitoring to include errors and performance metrics.

Taking a metrics-driven, collaborative approach ensures crash insights get translated into meaningful stability gains that improve user experience.

Testing and Quality Assurance

Testing is crucial for identifying edge cases and reliability issues before software reaches end users. Key aspects include:

Importance of Testing

Apps should incorporate unit, integration, performance, security, and usability testing to catch various error conditions. Test coverage directly correlates with stability. Prioritizing testing delivers outsized reliability gains per engineering hour invested.

Automated Testing 

Automated UI tests, API testing, crash testing, and unit test suites make testing more reliable and efficient. Tests can be run frequently and effortlessly to catch regressions. Useful frameworks include Appium, Espresso, XCTest, and JUnit.

Beta Testing

Real-world testing with a small set of users helps discover bugs that slipped through testing. Beta builds can collect additional analytics to measure crash rates, usage flows, network conditions, and other variables. 

User Feedback

Crowdsourced user feedback via app store reviews and support channels provides indications of real-world issues. Trends can inform development priorities and stability testing criteria before major releases.

Overall, testing sets the quality baseline, while user-reported issues and crash analytics reveal the quality threshold actually achieved. Both are essential for engineering teams to systematically improve reliability.

Continuous Improvement

Stability management is an ongoing discipline requiring continuous investments. Key aspects include:

Reviewing Error Handling  

Revisit the error handling code at least once a quarter to address technical debt. Refactor redundant logic, upgrade outmoded practices, and optimize usability. Evaluate if business logic changes necessitate new error flows.

Updating Best Practices

Evolve error-handling playbooks as platforms release new capabilities, tools get updated, and innovations emerge. Attend conferences, read blogs, and discuss learnings with peers to stay updated.

Incorporating Insights

Prioritize changes that address usability pain points highlighted in app reviews and support tickets. Let crash trends uncovered during monitoring guide the engineering roadmap. User feedback loops fuel continuous enhancement.

Proactive self-examination coupled with user insights will help development teams achieve exponentially greater stability and reliability over time. The compounding benefits are well worth the incremental effort.

By following the strategies outlined in this guide, mobile developers can meet and exceed user reliability expectations. The business upside from enhanced stability and user trust is too big to ignore. It’s time to declare war on crashes!