The Essentials of Browser Compatibility Testing

The Difference Between Cross-Browser and Compatibility Testing

So, what is browser compatibility testing, and how is it different from compatibility tests? The naming gives it all up. Cross-browser testing is a subset of compatibility testing—just like device compatibility testing, for example. While compatibility entails various aspects of software’s behavior across environments, cross-browser testing focuses on browsers specifically.

Here’s an ultimate cheat sheet on cross browser testing vs compatibility testing:

• Compatibility testing accounts for variations in operating systems, device types (mobile, desktop, tablet), screen resolutions, browser versions, hardware capabilities, and network conditions.
• Cross-browser testing checks if a website or web application functions identically across different web browsers and their versions, verifying consistent visual rendering, functionality, and user experience.

Now, let’s zoom in to explore this particular part of compatibility testing and learn about cross-browser testing in more detail.

Understanding the Browser Landscape

So, how to do compatibility testing? You need to comprehend the scope of work, or, in other words, figure out the browsers in all their diversity. The web browsing ecosystem is increasingly complex and dynamic. As a user, you might stick to a single app for all your personal and work tasks. It could be the same for other users but with a different browser. It can be a matter of personal preference or specific limitations—for instance, due to your company’s policy.

So, what we’ve got to remember:

• There’s a diversity of browsers.
• Not all of them are equally popular.
• New browsers keep appearing.
• The majority of them require attention.

Browsers chrome with different rendering engines, performance characteristics, and feature support. Understanding their particularities is fundamental to effective compatibility testing in software testing.

Overview of Major Browsers

So, what options do we have nowadays (and what do we need to test the software on)? There are five browsers you’ll want to include in your QA strategy:

• Google Chrome—66.3%. Dominant across desktop and mobile platforms. Strong in both developed and emerging markets.
• Apple Safari—17.99%. Driven by iOS and macOS users. Significant market share in North America and Western Europe
• Microsoft Edge—5.33%. Steady growth since adopting the Chromium engine. Strong presence in enterprise and Windows environments.
• Mozilla Firefox—2.62%. Stable user base. Popular among developers and privacy advocates.
• Samsung Internet—2.3%. Preinstalled on and optimized for Samsung devices.
• Opera—2.09%. Niche but loyal user base. Strong in some international markets.

All data is provided by Statcounter GlobalStats and is relevant as of February 2025.

Note that this is the market share for browsers used on all platforms worldwide. The data for desktop, tablet, and mobile use will be a bit different. The same goes for each region. For instance, China shows different patterns with local browsers like UC Browser. Developing markets often have different preferences due to device affordability and network conditions.

You can check these data on Statcounter or a similar platform. That’s a good starting point for a new website or app. If your platform is live, and you track the performance with Google Analytics or a similar tool, look for data inside. It’ll be more illustrative for your case.

There are several emerging browsers that challenge competitors by their focus on specialized features. To name a few:

• Brave Browser. Blockchain-integrated privacy browser with built-in ad and tracker blocking. Has cryptocurrency rewards for users. Focuses on user privacy and reduced data tracking.
• Vivaldi. Highly customizable browsing experience with advanced tab management. Built for power users and productivity. Offers extensive customization options.
• Tor Browser. Emphasizes anonymity and privacy. Routes traffic through multiple encrypted nodes, preventing tracking and surveillance. Popular among privacy-focused users.

Does it mean you need to include those in your browser compatibility testing strategy, too? Probably, no. Or, at least, not yet. For now, emerging browsers are just niche alternatives. They’re driving innovation by challenging data privacy norms and introducing novel user experience concepts. It may be enough to push traditional options to address specific user needs beyond standard browsing. But that’s it—for now.

Mobile vs. Desktop Browsers

It’s evident that cross browser compatibility testing is necessary because of the screen variations. It’s hardly surprising that viewing the same web pages on a 15.3-inch MacBook screen and a 6.1-inch iPhone screen requires adjustments. And adjustments require testing. And that’s just two devices by Apple alone.

Well, mobile and desktop browsers also differ fundamentally. They differ in design, functionality, and user interaction.

Desktop browsers come with:

• Larger screen real estate.
• Precise mouse and keyboard interactions.
• More complex UI elements.
• Higher processing power.
• Multiple window and tab management.

Mobile browsers, by contrast, are optimized for:

• Touch-based interactions.
• Smaller screen sizes.
• Limited processing resources.
• Gesture-based navigation.
• Data conservation.
• Simplified user interfaces.

So, there are several key differences that your product team (ideally, represented by a QA engineer) should account for during mobile browser compatibility testing:

• Rendering capabilities. The difference in screen sizes and hardware results in browsers using different rendering engines and approaches to handle web content.
• JavaScript performance. Mobile browsers have slower JavaScript execution due to hardware limitations and power-saving constraints. Desktop browsers can handle heavier scripting and more complex logic.
• Touch event handling. Mobile browsers rely heavily on touch gestures like swiping, pinching, and tapping. It requires different event handling mechanisms compared to the mouse-based interactions on desktops.
• Responsive design implementation. Mobile browsers prioritize responsive design to adapt content to various screen sizes and orientations. Desktop browsers focus more on flexible layouts and scaling for larger displays and multiple window sizes.
• Resource management. Mobile browsers are designed to conserve battery life and manage memory more efficiently. Desktop browsers can allocate more RAM and CPU power for handling complex web apps.
• Network condition adaptability. Mobile browsers operate under varying network conditions more often. Features like data compression and caching are critical to enhance performance. Desktop browsers typically rely on stable, high-speed connections.

To provide sufficient use test coverage, you need to address these and similar platform-specific aspects. Keep this in mind when planning your QA process and preparing test documentation.

Browser Compatibility Testing Checklist

A comprehensive compatibility testing checklist may include a few hundred points. Speaking about the essential testing points, it’s advisable to verify the following:

• Layout and design consistency.
• Responsive design functionality.
• Navigation and menu interactions.
• Form submission and validation.
• JavaScript functionality.
• CSS animations and transitions.
• Third-party plugin compatibility.
• Performance metrics.
• Mobile responsiveness.
• Touch event handling.
• Screen reader accessibility.
• Video and multimedia support.
• Local storage and cookie handling.
• AJAX and dynamic content loading.
• Font rendering.
• SVG and canvas graphics.
• …

If we speak about a cross browser compatibility testing checklist as a test artifact, here’s an example of how you can format one for an online store:

Remember to update your checklist as your store or web app grows. It’s essential to add every new feature or alteration. Even if you’ve done with the development, you’ll need to run cross-browser testing once in a while—after a new browser version becomes available. You’ll want to keep the software running for users who update to the latest version, right?

Tools for Browser Compatibility Testing

Our QA team prefers working with physical devices. Yet, browser compatibility testing has become increasingly sophisticated. Compatibility testing tools like BrowserStack help extend the courage, providing access to more real devices and browsers. Also, there are test automation tools that enable us to automate repetitive checks for faster test execution and higher accuracy. Here are some examples of browser compatibility testing tools that may come in handy.

Browser Testing Platforms

Cloud-based browser testing platforms provide instant access to multiple browser and device configurations. Thanks to these services, teams don’t need to build extensive local infrastructure to ensure sufficient testing. They just connect a browser compatibility testing tool capable of modeling the needed scenarios.

• BrowserStack. A cloud-based platform that provides real-time and automated testing on various browsers and devices.
• Sauce Labs. Offers cross-browser and mobile testing with Selenium, Appium, and other automation frameworks.
• LambdaTest. Provides manual and automated cross-browser testing with real-time debugging tools.
• CrossBrowserTesting (by SmartBear). Enables live, automated, and visual testing across multiple browsers and devices.

Browser Developer Tools

Built-in browser developer tools provide granular insights into web application performance, rendering, and potential compatibility issues. With their help, you can look into different aspects of a tested web app. The features range from responsive design mode to performance profiling, network request analysis, and more.

• Google Chrome DevTools. A built-in set of web development and debugging tools for inspecting HTML, CSS, and JavaScript performance.
• Mozilla Firefox Developer Tools. Offers advanced debugging features, network monitoring, and accessibility testing.
• Safari Web Inspector. Apple’s native tool for debugging web content on macOS and iOS devices.
• Microsoft Edge DevTools. Provides comprehensive debugging, performance profiling, and accessibility tools.
• Brave Developer Tools. Based on Chrome DevTools, with added privacy-focused features for debugging web pages.
• Samsung Internet Developer Tools. An extension for Chrome that allows debugging and testing on Samsung’s mobile browser.

Virtual Machines, Emulators, and Simulators

Though less effective than real devices, virtual alternatives let you check scenarios that otherwise would have been ignored. Virtual devices provide controlled environments for cross-browser testing. QA engineers can simulate diverse system configurations without maintaining multiple physical devices.

• Oracle VM VirtualBox. Free and open-source virtualization platform for running multiple OS environments.
• Microsoft Hyper-V. A built-in Windows virtualization platform for running different OS instances.
• Parallels Desktop (for Mac). A macOS-based virtual machine for running Windows and Linux environments.
• Android Emulator (via Android Studio). Official Android environment for testing web and app performance.
• iOS Simulator (via Xcode). Apple’s native tool for testing web content on iOS devices.
• Responsive Design Checker. A web-based tool for quick layout testing on different devices and resolutions.

How to Do Browser Compatibility Testing

There’s one important thing to understand when figuring out how to perform browser compatibility testing. Cross-browser testing is rarely an isolated process. So, in practice, it’ll be a part of a more comprehensive QA framework. To describe it schematically, the step-by-step testing process will entail the following activities:

1. Define the target browsers and devices. Identify the browsers, versions, and operating systems your target audience uses. Prioritize based on market share and user analytics data.
2. Set up the testing environment. Decide what real devices, testing platforms, and virtual devices you’ll use to replicate different environments.
3. Prepare test documentation. It can be a checklist or test cases focusing on key functionalities, UI responsiveness, performance, and compatibility with browser-specific features.
4. Run functional testing. Verify core functionalities such as navigation, form submission, and interactive elements across different browsers.
5. Check UI and layout. Test how elements like fonts, images, buttons, and grids render on different screen sizes and resolutions.
6. Test JavaScript and CSS. Ensure that browser-specific CSS properties and JavaScript functions behave as expected.
7. Evaluate basic performance. Analyze loading speed, responsiveness, and resource usage on different browsers and devices.
8. Verify responsiveness and touch events. Use responsive design tools and mobile emulators to test touch gestures, scrolling behavior, and adaptive layouts.
9. Test under different network conditions. Simulate slow connections or offline modes to check how the website handles caching and performance.
10. Identify and document issues on the way. Log browser-specific bugs and inconsistencies for the development team to fix.
11. Retest the flawed parts after fixes. Check everything on the same environments after improvements to ensure that compatibility changes have been applied successfully.

That’s a sequence for manual cross-browser compatibility testing. If you plan for test automation, there will be a few crucial things to take into account.

To start with, you’ll need to choose the relevant scenarios for automated browser compatibility testing—frequently run, with clear positive/negative results, etc. Also, writing test cases is mandatory. They will become the basis for automated scripts. This will be followed by the framework setup and ongoing test suite maintenance.

Given the complexity and the diverse browser landscape, it’s best to involve professional QA engineers in this process. Whether you decide to go with hiring specialists in-house or outsourcing browser compatibility testing services, make sure to get the right expertise. It matters a lot.

Conclusion

Testing browser compatibility is not just a technical requirement. It’s a critical business strategy. Successful web experiences create seamless, intuitive interactions that delight users across every device and platform. And that’s what every business should strive for. In the end, little things that make user experience define their readiness to come back to your platform and become a loyal audience.