Mastering Cross-Browser Compatibility: A Guide For Testers


As technology evolves, ensuring cross-browser compatibility testing has become more crucial than ever. However, not everyone can keep pace with these advancements. Some prefer using older technologies, which may not seamlessly integrate with newer updates. Consequently, this disparity can impede their browsing experience, leaving them dissatisfied with the website.

Cross-browser testing safeguards against leaving anyone behind due to missed updates. This article will explore everything you need to know about cross-browser compatibility testing.

What is Cross-Browser Compatibility Testing?

Cross-browser compatibility testing ensures a website functions optimally across browsers like Chrome, Firefox, Safari, and Edge. Each browser has its own unique rendering engine and way of interpreting code, which can lead to inconsistencies in how webpages are displayed and function.

Cross-browser compatibility testing aims to guarantee a smooth, uniform user experience regardless of the browser used to access the site. Comprehensive testing of all features, layouts, and functionalities is done to pinpoint any discrepancies that may pop up across different browser environments. Conducting this testing allows developers and QA teams to catch and fix compatibility issues, improving accessibility and usability for all site visitors.

Types of Cross-Browser Compatibility Testing

Following are the main types of cross-browser compatibility testing:

  • Backward compatibility testing– Verifies that a new software version works without issues with configurations, data, and components from previous versions. It ensures existing users can upgrade smoothly.
  • Forward compatibility testing– Validates that software functions correctly with future hardware, operating systems, and other components. It confirms the software will remain compatible as dependencies evolve.
  • Browser compatibility testing – Validates consistency across different web browsers and versions. It is critical for web apps.
  • Mobile compatibility testing – Confirms apps function correctly across diverse mobile devices and platforms like iOS and Android.
  • Device compatibility testing – Checks operation with external devices like printers, Bluetooth, and USB devices.
  • Network compatibility testing – Assesses performance under different network environments like Wi-Fi, 3G, 4G, 5G, etc.
  • Operating system testing – Verifies seamless functionality across operating systems like Windows, macOS, Linux distributions, etc.

Difference Between Cross-Browser and Compatibility Testing

Cross-browser and compatibility testing are related techniques in software testing that aim to uncover issues arising from differences between environments. However, their scopes and purposes differ.

Cross-browser testing specifically focuses on validating web applications across different web browsers and their versions. The objective is to pinpoint differences in appearance, functionality, layout, and behavior caused by variations in how browsers interpret code and adhere to standards. Thorough cross-browser testing guarantees a uniform user experience, regardless of which browser is used to access the application.

Compatibility testing goes beyond browsers to validate software on various platforms, including operating systems, devices, screen sizes, system configurations, and other factors. The aim is to assess overall software compatibility and quality across diverse intended usage environments. Operating systems like Windows, macOS, iOS, and Android are tested for web applications. For desktop software, testing occurs on configurations representing the minimum and recommended hardware.

While cross-browser testing fits under the umbrella of compatibility testing for web apps, compatibility testing is much broader. It validates functionality, UI/UX, integration, and performance based on the full spectrum of target user environments.

For web applications specifically, extensive cross-browser testing across desktop and mobile browsers remains a priority subset of overall compatibility testing. Testing across old and new browsers, browsers on different operating systems, and browser versions catches inconsistencies. 

Compatibility testing may not involve browsers at all for software that doesn’t operate on the web. But validating installations, upgrades, integrations, UI, speeds, and more across the intended usage environments is still critical. Compatibility testing often occurs alongside other testing types like functional, regression, and user acceptance testing.

So, all cross-browser testing could be considered a form of compatibility testing, but compatibility testing also encompasses much more than just browsers and is vital for all software types.

What are Cross-Browser Compatibility Issues?

To ensure your application works well on different browsers, it is essential to know about common problems with compatibility during development.

  • Inconsistent CSS Rendering:

Inconsistent CSS rendering across different browsers is a common compatibility issue developers face. Because browsers interpret CSS code differently, the same site can have varying layouts, spacing, fonts, and more, depending on the browser. Developers should use standardized, compliant CSS properties and test sites across target browsers during development to promote consistent rendering. CSS resets and normalization scripts can also help enforce uniform styling across browsers.

  • JavaScript Compatibility Problems:

JavaScript behavior and support vary significantly between browsers, especially when using newer ES6+ features not fully supported in legacy browsers. Testing code across target browsers helps uncover compatibility gaps.

  • Lack of Support for Newer HTML5/CSS3:

Many older browsers lack support for newer HTML5 and CSS3 features. Using cutting-edge, unsupported features can break layouts and functionality in older browsers. 

  • Inconsistent Handling of Touch Events:

Mobile browsers differ in handling touch and gesture events like swiping, pinching, etc. This can create usability issues on touch-optimized sites. Testing on physical mobile devices rather than simulators/emulators reveals these inconsistencies across browsers.

  • Browser-Specific Bugs:

Bugs in specific browser versions can sometimes break sites. Rigorous cross-browser testing during development helps uncover and fix such bugs. Workarounds may be needed for certain browser quirks.

Importance of Cross-Browser Compatibility Testing

Following are the reasons why cross-browser compatibility testing is essential:

  • Ensure a uniform user experience:

When creating a website or application, it’s important to remember that people access the internet using all sorts of different browsers – Chrome, Firefox, Safari, Edge, mobile browsers, and more. Each browser may display web pages a little differently.

Without checking for cross-browser compatibility, parts of your website might not work properly on some browsers. This can lead to a disjointed experience for users. Ensuring cross-browser compatibility helps provide a uniform experience that keeps visitors engaged across browsers.

  • Expand audience reach:

With the diversity of available browsers, different segments of your audience likely prefer different browsers based on their needs and environments. For example, many corporate offices use Internet Explorer for legacy reasons. Apple device owners predominantly use Safari. If you only test and optimize for one browser like Chrome, you may alienate visitors who exclusively use others. Cross-browser testing maximizes your market reach and prevents limiting your audience.

  • Maintain brand credibility:

When a website has issues on specific browsers, it reflects poorly on your brand. It gives the impression that proper care and attention to detail were not invested in the site development. On the other hand, a site working seamlessly across major browsers makes your brand appear more professional, reliable, and trustworthy. It demonstrates you value accessibility and the user experience.

  • Mobile compatibility:

With mobile internet usage rising, ensuring your site provides an optimal experience on mobile browsers is essential. Mobile browsers like Safari on iOS and Chrome on Android have unique constraints like smaller screens, touch interfaces, and different HTML/CSS support. Testing helps ensure your site’s design resizes and adapts appropriately on mobile devices.

  • Simplifying maintenance:

When a site works consistently across browsers, it reduces the ongoing maintenance burden. There are fewer browser-specific bugs and issues to fix after launch. Smoother cross-browser performance saves time and effort on updates.

  • Accessibility compliance:

Accessing your website to people with disabilities is crucial for legal compliance in many regions. It also demonstrates social responsibility. Testing for compatibility with screen readers, magnification software, and other assistive tools enables equal access.

  • Global audience reach:

Users worldwide access your site through diverse, locally popular browsers. Testing ensures your site displays properly in those browsers, including correct rendering of regional languages, fonts, and characters. This allows you to effectively reach and engage global audiences.

  • Competitive advantage:

Sites that embrace cross-browser testing demonstrate technology leadership in their field. The improved user experience pays dividends in higher visitor engagement and loyalty. When competing sites have browser compatibility issues, your site gains an advantage through better performance and convenience.

Best Practices for Cross-Browser Compatibility Testing

Here are the best practices for cross-browser compatibility testing:

  • Establish Target Browser and Device Coverage:

Identify all browsers and versions your audience uses across relevant devices and platforms to maximize compatibility. Create a matrix to map the required test coverage and guide development priorities. Ensure adequate testing on both mainstream and older browsers still in use. Update as usage data changes.

  • Leverage Frameworks for Cross-Browser Optimization:

Web development frameworks abstract away many cross-browser issues and automatically generate standardized, responsive code. Built-in compatibility helps focus efforts on functionality over implementation details. Frameworks also speed up development with reusable code modules. Conduct testing to ensure the framework delivers on compatibility.

  • Employ Automated Testing Tools:

AI-powered test orchestration and execution platforms like LambdaTest, allow automation testing that significantly accelerates validation across browsers and devices. Rather than manual, repetitive testing, automated scripts can simulate user journeys across the desired matrix continuously and without effort. Integrate testing into the development workflows for rapid results. Prioritize automating repetitive test cases.

  • Validate Code to Web Standards:

Many compatibility issues arise from syntax errors or non-standard code. Eliminate validation errors and warnings to improve quality. Use validation automation during development to prevent new issues.

  • Conduct Regression Testing:

Changes and updates often introduce new compatibility bugs. Conduct comprehensive retesting across all targeted browsers and devices with each iteration before deployment. Regression testing verifies fixes and prevents inadvertent issues. Automate where possible.

  • Gather Real-World User Feedback:

Enable user feedback channels like “Report a Bug” buttons to gather compatibility issues from the field. Monitor social media and app store reviews as well. Diagnosing and rapidly responding to reported problems is a priority.

Following structured compatibility practices reduces cross-browser bugs and provides reliable experiences for users.


Comprehensive testing requires clearly defining the scope by deciding which target browsers, operating systems, devices, and assistive technologies to include based on analytics of the user base. Automated testing tools can accelerate the execution of test suites across multiple platforms simultaneously. Testing should be ongoing throughout development to detect issues early when fixes are simpler.

While automated checks are extremely useful, manual real-world testing on desktop and mobile browsers remains essential to simulate genuine user interactions. The focus should remain on optimizing subjective user experience, not just technical issues. Input from real users can further enhance testing by uncovering usability gaps.

As technology progresses and changes rapidly, with new versions and devices constantly emerging while others become outdated, cross-browser testing becomes crucial to ensure that websites and web applications function correctly for all users. In this article, we’ve explored browser compatibility, its significance, and related issues. Cross-browser compatibility remains a continuous challenge, but by adopting the right approach and adhering to best practices, we can enhance its diversity and adaptability in the future.