Web applications have become an integral part of our lives, from online banking and social media to online stores and enterprise systems. But behind the convenience and functionality lies the complex work of quality assurance. Web application testing is not just about finding bugs, but about ensuring security, performance, and user satisfaction.

In this article, we will explore:

• How and why testing became a necessity;
• The most challenging moments in testing;
• Interesting cases from practice that changed approaches to testing.

1.1. The early days of the Internet: chaos and lack of standards
In the 1990s, when the Internet was just beginning to develop, websites were simple and static. However, even then, there were problems:

• incorrect display in different browsers (Netscape Navigator vs. Internet Explorer).
• broken links due to manual content management.
• errors in forms (such as incorrect processing of user data).

These issues led to a loss of users and revenue, prompting developers to consider a systematic approach to quality assurance.

1.2. The First Commercial Web Applications: When Mistakes Cost Millions
With the advent of e-commerce (Amazon, eBay) and online banking in the late 1990s and early 2000s, testing became critical.

The Amazon Case: A Bug in the Shopping Cart
In 2000, Amazon experienced a bug that allowed users to see other people's orders in their shopping carts. This led to widespread complaints and a temporary decline in trust to the platform. After this incident, Amazon implemented strict security and data testing procedures.

Online Banking: Vulnerabilities and Fraud
In the early 2000s, several banks faced issues due to vulnerabilities in their web applications:

• SQL injections allowed attackers to gain access to customer data.
• errors in payment processing led to double charges or no charges at all.

These incidents demonstrated that security and functionality testing is not a luxury, but a necessity.

1.3. The emergence of dynamic web applications: new challenges
With the development of technologies (AJAX, JavaScript, frameworks like Angular and React), web applications became more complex. This led to new problems:

• asynchronous data loading could "break" the application's logic.
• errors in JavaScript caused buttons or forms to stop working.
• cross-browser issues — the website could look different in Internet Explorer and Firefox.
• The case of Gmail: slow performance in IE6.

When Google launched Gmail in 2004, many users complained about slow performance in Internet Explorer 6. It turned out that the browser was not optimised for dynamic content loading. This led Google to focus more on performance and compatibility testing.

1.4. Social media and the viral effect of errors
With the advent of Facebook, Twitter, and other social media platforms, errors began to spread rapidly. For example:

• errors in content display (such as posts with broken characters).
• privacy issues (when users have seen other people's messages).

These cases have shown that testing should be not only functional, but also user-experience oriented.

1.5. The Mobile Revolution: adaptability as a necessity
With the advent of smartphones (iPhone in 2007), web applications had to adapt to new devices. The first mobile versions of websites often:

• displayed incorrectly on small screens;
• loaded slowly due to unoptimised images;
• had broken interface elements (for example, it was impossible to click on a button).

This led to the development of responsive design and testing on different devices.

2.1. User experience (UX) as the foundation of success
A web application is the face of a company. If it is slow, displays incorrectly on different devices, or contains errors, users will leave to competitors. According to research, 53% of users leave a website if it takes more than 3 seconds to load (Google, 2024). Testing helps to avoid such losses.

2.2. Security: Protecting Data and Reputation
Data breaches, hacks, and vulnerabilities are not only financial losses, but also a blow to reputation. Security testing (pen-tests, vulnerability scanning) helps to identify weaknesses before they are exploited by attackers.

2.3. Cross-platform compatibility
A web application should work equally well on all devices and browsers. Testing on different platforms (Windows, macOS, Android, iOS) and browsers (Chrome, Firefox, Safari, Edge) ensures that users get the same experience.

3.1. Dynamic data and asynchronous requests
Modern web applications actively use AJAX, WebSockets, and other technologies for dynamic data loading. Testing such scenarios requires a deep understanding of the application's logic and specialised approaches.

3.2. Load Performance Testing
How will the application behave if 10,000 users log in simultaneously? Stress testing and load testing help identify bottlenecks and optimise performance.

3.3. Security Testing: Combating Vulnerabilities
Web applications are often targeted by attacks such as SQL injection, XSS, and CSRF. Testers should be able to identify such vulnerabilities and prevent their exploitation.

3.4. Testing UI/UX on different devices
Adaptive design is not only beautiful, but also functional. Testing on different screen resolutions, checking the usability of the interface and accessibility (for example, for people with disabilities) is a challenging but necessary task.

4.1. A button that "disappeared" on iPhone
In one of the projects, the "Pay" button was not displayed on the iPhone due to a CSS error. The testers discovered that the issue was related to media queries and fixed it before the release.

4.2. Data leakage due to incorrect cache settings
In another case, the testers identified that sensitive user data was being cached and was accessible to other users. The issue was resolved by changing the server settings.

4.3. Chatbot testing: How to trick AI?
When testing a chatbot for a bank, it was discovered that it was revealing sensitive information when certain requests were made. This led to the refinement of the request processing algorithms.

Testing web applications is not just about finding bugs, but about ensuring quality, security, and user satisfaction. Companies that prioritise testing save money on bug fixes after release and build customer trust.

To get professional help with app testing, you can always contact the “ROOT CODE” team. We can make sure that your website is fast and secure, and that you make money!