Top 15 Common Bugs in Mobile Apps and How to Fix Them

In this article, we will explore the top 15 common bugs found in mobile apps and provide insights on how to fix them. By addressing these bugs, developers can create a seamless user experience and ensure their apps function flawlessly.

As experienced smartphone users, we have developed an eye for spotting defects in applications quickly. From frustrating interfaces to buttons that cause apps to crash, we have encountered various issues. While it is essential not to overlook the most glaring bugs, our team has compiled a list of common problems to highlight the significance of a mobile engineer's role for both developers and end-users.

SSL Certificate Handling Flaws

Despite the presence of built-in certificate handling code in iOS and Android, errors can still arise when app developers create their implementations. Exploiting this opportunity, hackers can manipulate the app into accepting counterfeit certificates that resemble the app's legitimate server. As a consequence, the presence of certificate handling flaws introduces vulnerabilities, such as man-in-the-middle attacks, which enable attackers to manipulate and tamper with incoming information.

Data Leakage

While the mobile operating system provides a certain level of protection, it is not sufficient to prevent determined individuals from examining the internals of mobile apps. Mobile developers must remain vigilant about the fact that mobile apps can be reverse-engineered. This process can potentially expose sensitive information, including leaked data such as API keys, social network API tokens, AWS credentials, and RSA private keys. Developers must prioritize security measures and adopt practices that safeguard against these risks.

Client-Side Validation

Security issues often arise when developers heavily rely on client-side validation for sensitive actions that require authentication. It is important to note that client-side validation bugs are more commonly found in mobile apps compared to web apps.

Client-side validation, while useful for improving user experience and providing immediate feedback, should never be solely relied upon for security purposes. Important security checks and validations should be performed on the server side to ensure the integrity and confidentiality of sensitive data and to prevent malicious activities.

Developers must prioritize a layered approach to security, implementing both client-side and server-side validation mechanisms, to effectively mitigate security risks and protect against potential vulnerabilities.

Insecure Direct Object Reference

IDOR vulnerabilities are frequently encountered within the REST API of an application. Sophisticated manipulations by malicious actors allow them to gain unauthorized access to confidential messages belonging to the victim.

Outdated Vulnerable Components

Despite the prominence of cybersecurity in the digital realm, app developers often overlook the potential vulnerabilities present in the components they utilize. This oversight can manifest in various ways, such as neglecting to promptly address or upgrade the foundational platform, frameworks, and dependencies, as well as failing to thoroughly test the compatibility of updated, upgraded, or patched libraries.

Compatibility Bugs

In the digital era, it is essential to prioritize ensuring the compatibility of mobile apps with a wide range of devices. However, this task poses a significant challenge due to the multitude of hardware and software functionalities packed into smartphones today, which can be combined in countless unforeseen combinations.

Inconsistencies in Page Layout Across Devices

When end-users access an app using devices of varying screen sizes, rendering inconsistencies, misalignments, and overlapping can occur. These issues, particularly in e-commerce applications, have the potential to result in substantial revenue losses. It's analogous to a shop window becoming blurry when a potential customer moves closer, potentially detracting them from making a purchase.

Unnecessary Navigation

If an app requires a guide, it can indicate a fundamental usability problem. Ideally, an app should be intuitive and user-friendly enough that users can navigate and understand its features without the need for explicit instructions or a separate guide. A well-designed app should provide clear and intuitive user interfaces, logical navigation pathways, and appropriate feedback to guide users through the application without confusion or difficulty. However, in some cases, a brief tutorial or onboarding process may be necessary to introduce unique or complex features to users. The key is to strike a balance between simplicity and functionality, ensuring that the app is accessible and understandable for the majority of users without excessive reliance on external guides.

Lacking Landscape Mode

A well-designed mobile app should be able to adapt seamlessly to both portrait and landscape orientations. Additionally, many experts suggest that different UI approaches should be considered for each orientation, particularly when the app includes video content.

“Work-as-designed” Performance Issues

Indeed, a group of issues can arise due to flaws in app design. These issues occur because the application operates exactly as intended but the design itself possesses inherent flaws. Some common examples include non-scalable architecture, improper loading techniques, excessive synchronization, and more.

Non-scalable architecture can hinder the app's ability to handle increased user traffic or growing data volumes efficiently. Improper loading techniques may result in slow loading times or an inefficient use of resources. Excessive synchronization can lead to delays or bottlenecks in data processing.

Addressing these design-related issues requires careful planning and consideration during the development process. Developers should strive to create scalable architectures, employ efficient loading techniques, and strike a balance with synchronization to ensure the app functions optimally and provides a seamless user experience.

Memory-related Issues

Design-related issues in app development can indeed encompass memory leakage, improper caching, and insufficient memory allocation.

Memory leakage occurs when the app does not properly release memory resources, leading to a gradual reduction in available memory over time. Improper caching refers to inefficient or ineffective storage of temporary data, leading to performance degradation or incorrect data retrieval. Insufficient memory allocation can result in application crashes or poor performance due to limited available memory for the app to operate.

Addressing these design issues requires careful memory management practices, implementing efficient caching mechanisms, and ensuring adequate memory allocation for optimal app performance. Developers should prioritize proper memory handling and caching strategies to avoid these detrimental issues in their app design.

Interfacing Performance Issues

Indeed, a range of issues can be triggered by various factors such as using outdated drivers or libraries, neglecting regular database housekeeping, missing database indexes, or encountering logging issues.

Using outdated drivers or libraries can introduce compatibility issues or security vulnerabilities, impacting the overall functionality and stability of the application. Neglecting regular database housekeeping, such as archiving or purging old data, can lead to increased storage usage, slower database performance, and potential data corruption. Missing database indexes can affect query performance and result in slower response times. Logging issues, such as excessive logging or inadequate error handling, can impact system performance, cause storage bloat, or potentially expose sensitive information.

To mitigate these issues, developers must ensure they are using up-to-date drivers and libraries, maintain regular database housekeeping routines, implement appropriate database indexing strategies, and establish robust logging practices. Proactive monitoring and regular maintenance can help identify and rectify potential issues, ensuring the smooth operation of the application.

Slow Response Time

Indeed, there are several common reasons why a mobile app may experience slowness. These include:

1. Network latency: Slow network connections or high latency can significantly impact the app's performance.

2. Unoptimized encrypted connections: If encrypted connections are not properly optimized, it can lead to increased overhead and slower data transmission.

3. Sluggish server speed: If the server that the app interacts with is slow in processing requests, it can cause delays in data retrieval or updates.

4. Chatty conversations: Excessive back-and-forth communication between the app and the server, such as making frequent API calls, can introduce delays and impact performance.

5. App overcrowdedness with data: If the app's data storage becomes cluttered or overloaded with excessive data, it can slow down data retrieval and processing operations.


Indeed, apps can crash due to unnoticed bugs, and it is crucial to thoroughly test any added feature or functionality. Testing helps identify and resolve software defects before they affect the end users. By conducting comprehensive testing, including unit testing, integration testing, and user acceptance testing, developers can uncover and fix potential issues that could lead to crashes. Additionally, implementing regular quality assurance processes and utilizing automated testing tools can further enhance the app's stability and reliability.

App development is indeed a complex process and ensuring the quality of your app is crucial for maintaining your reputation and providing a positive user experience. The checklist you provided covers some important aspects of bug detection.

However, here are a few additional points you may want to consider:


1. Test the app on various devices: It's essential to test your app on a wide range of devices to ensure compatibility and functionality across different screen sizes, hardware configurations, and manufacturers.

2. Test different data scenarios: Evaluate how your app handles different data scenarios such as low network connectivity, slow internet speeds, and large data volumes to ensure optimal performance.

3. Test for usability and user experience: Conduct user testing to gather feedback on the app's usability, navigation, and overall user experience. This can help identify and address any potential issues or areas of improvement.

4. Security testing: Verify the app's security features by conducting penetration testing and vulnerability assessments to identify any potential security risks and ensure the app's data protection.

5. Test for edge cases: Test the app under unusual or extreme conditions, such as low battery, low storage space, or high resource usage, to uncover any unexpected bugs or issues.

6. Regression testing: Perform regression testing to ensure that new updates or changes to the app have not caused any previously fixed bugs to resurface.

Remember that the checklist you provided is a starting point, and the specific testing requirements may vary depending on the complexity and functionality of your app. Regular testing and continuous improvement are essential to deliver a high-quality app to your users.


Mobile app development is a complex process that requires attention to detail and thorough testing. By addressing these top 15 common bugs, developers can deliver high-quality apps that provide a seamless and enjoyable user experience. Prioritizing security, performance optimization, compatibility, and usability will help create apps that meet user expectations and stand out in a competitive market.

To ensure comprehensive testing and bug detection, developers can rely on WeTest Mobile App Testing. WeTest integrates cutting-edge tools such as automated testing, compatibility testing, functionality testing, remote device testing, performance testing, and security testing. With WeTest, developers can cover all testing stages of their apps throughout their entire lifecycle, ensuring optimal performance and reliability.

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