Cross browser testing: A complete introductory guide

Web applications today cater to a variety of platforms, browser engines, and devices. Users across the globe may use any combination of browser, device, and platform to access an application.

Cross-browser testing helps to create a consistent behavior across different browsers on different platforms and devices for an application.

In this post, we’ll learn what cross-browser testing is, why it’s important, how to perform it, how to navigate any challenges one might run across, and explore some of the best practices.

What is cross-browser testing?

TL;DR: Cross-browser testing verifies that a web application works consistently across different browsers, devices, and platforms, covering both functional behavior and visual appearance.

Cross-browser testing, also known as browser compatibility testing, is the process of validating functional and non-functional aspects of an application across different browsers on different platforms and devices.

Functional aspects of an application include features such as log-in, sign-up, CRUD operations, etc.

Non-functional aspects include the layout or user interface, performance, and accessibility of the application. As the browser, device, and platform vary, the same interface may appear different, and the same features may work differently.

The dream behind the Web is of a common information space in which we communicate by sharing information. Its universality is essential.

Why is cross-browser testing important?

TL;DR: Different browser engines interpret web code differently. Cross-browser testing ensures consistent functionality, layout, and performance across browsers, preventing compatibility issues for users.

The web was designed to be a system that is both universal and accessible across different platforms and browsers.

As Tim Berners-Lee notes, “The dream behind the Web is of a common information space in which we communicate by sharing information. Its universality is essential.” Ensuring applications behave consistently across browsers is essential for maintaining that universality.

Modern web applications are a bundle of HTML, CSS, and JavaScript code. Under the hood, browsers utilize an engine to compile and execute an application’s client-side code.

Hence, two different browsers may interpret and execute the same line of HTML, CSS, or JavaScript code differently.

For instance, Chrome runs on the engine Blink, Safari uses WebKit, etc. Fragmentation of engines and platforms leads to differences and potential inconsistencies in various functional and non-functional aspects of the application.

These differences can result in bugs, changes in layouts, JavaScript errors, warnings on the console, performance issues, and so on.

Physical hardware also influences interactions between an application and a device, influencing the underlying engine that interfaces these interactions.

Key benefits of cross-browser testing

TL;DR: Cross-browser testing improves user experience, accessibility, engagement, and brand perception by ensuring applications behave consistently across browsers, devices, and platforms.

Some key benefits of cross-browser testing include:

1. Enhanced user experience

With a consistent interface and experience across browsers and platforms, users get a smooth, seamless, and consistent experience, enhancing the overall experience of the application.

2. Improved accessibility

Accessibility features vary widely across browsers and platforms. By detecting inconsistencies beforehand, teams can ensure more comprehensible accessibility.

3. Improved user engagement

When applications don’t break often across browsers and devices, users engage actively with them, leading to better conversion metrics and business outcomes.

4. Enhanced brand perception

A consistent experience across browsers for a wide spectrum of users creates a positive brand.

How does cross-browser testing enhance user experience?

TL;DR: By detecting compatibility issues early, cross-browser testing ensures consistent layouts, performance, and accessibility across environments, creating a reliable and predictable user experience.

User experience depends on consistency, predictability, and performance across various environments.

By identifying and addressing any inconsistencies that may arise from cross-browser testing, teams can ensure a rich and consistent user experience across different platforms, devices, and browsers.

Hence, an application’s layout, visual elements, performance, and accessibility appear the same regardless of the browser or device users use, which instills more trust in the user base and enables users to use the application to its full capability.

Who performs cross-browser testing?

TL;DR: Cross-browser testing is typically performed by QA engineers, SDETs, front-end developers, and sometimes designers or product managers during release validation.

Depending on the team size, different teams in an organization can share the responsibility of performing cross-browser testing.

1. QA engineers and SDETs

Quality assurance engineers and SDETs can design a test plan, write and run test cases, and automate scripts to create bug reports to perform cross-browser testing in a similar fashion.

2. Front-end engineers

Organizations that lack dedicated QA teams or SDETs, such as small- to medium-sized firms or start-ups, could utilize front-end engineers to perform cross-browser testing.

They are most familiar with the client-side code and have the most context to debug any issues or inconsistencies that arise due to cross-browser incompatibility.

They can perform development testing or include cross-browser testing in front-end testing to detect compatibility issues early on and resolve them.

3. Design teams/PMs

PMs and designers who often sign off releases from an end-user perspective may also perform cross-browser testing to ensure consistent behavior, performance, and experience across different browsers and devices.

It’s preferable to perform cross-browser testing as a continuous process and integrate it early in the development phase of the release cycle.

When should you perform cross-browser testing?

TL;DR: Cross-browser testing should occur throughout the development lifecycle—from development and pull requests to staging validation and post-release production checks.

It’s preferable to perform cross-browser testing as a continuous process and integrate it early in the development phase of the release cycle. Developers have more context on how functional and non-functional aspects of a release can behave differently on different browsers.

During the dev phase, engineers and developers can pay close attention to the cross-browser compatibility of their code and readily test these features as they’re developing them on different browsers.

Not only can this help detect cross-browser incompatibility early on, but it also helps to narrow down what aspects of a release can lead to faulty behavior post-release.

QA teams/PMs/SDETs can perform end-to-end cross-browser testing after a release PR is created or before it is merged. It’s also important to perform a sanity test after the release itself on production.

Cross-browser testing on real devices

TL;DR: Testing on real devices reveals hardware-level behaviors such as touch input, GPU rendering, and OS interactions that emulators and simulators cannot fully replicate.

While emulators and simulators are available to mimic a device and browser, which can help you perform cross-browser testing, the scope of that testing is limited and doesn’t provide the full experience.

Access to the actual engines, browser APIs, and device configurations is missing, which can lead to differences in the actual performance, CPU/GPU behavior, OS-level APIs, touch interactions, and so on.

With a real physical device, you get access to the physical hardware and the software underlying it, which interfaces your application and the user’s interaction.

You can actually validate real input modes such as touch, gestures, virtual keyboards, mouse activity, etc.

You can also validate the real performance offered by the browser and the underlying browser engine for metrics such as CPU/GPU usage, throttling, and battery optimizations.

Lastly, you can also experience how that browser and device handles OS- and browser-specific APIs such as notifications, permissions, and so on.

However, performing cross-browser testing on real devices entails a big challenge of maintaining a plethora of physical devices. Moreover, manually testing the application or release across all such devices can be time-consuming and cumbersome.

Performing cross-browser testing manually is essential, but relying on it alone can be extremely time-consuming.

Effortless integration and automation

TL;DR: Automation frameworks allow teams to run cross-browser tests in CI/CD pipelines, enabling faster execution, parallel testing, and consistent validation across environments.

Performing cross-browser testing manually is essential, but relying on it alone can be extremely time-consuming.

With automation frameworks, you can integrate cross-browser testing right into your existing CI/CD workflow and execute the automated scripts to run tests in parallel, speeding the entire testing process.

Moreover, this automated software testing integrates well with any CI services you’re using, like GitHub Actions, GitLab CI, etc., and also integrates well with dev tools through IDE plugins and CLI applications.

Through integration and automations, you can run cross-browser testing as seamlessly as a unit test.

Pre-testing considerations for cross-browser testing

TL;DR: Effective cross-browser testing begins with defining scope, creating a browser support matrix, standardizing coding practices, and preparing proper testing environments and tools.

Before you perform cross-browser testing, there are some considerations and preparatory steps that can make the testing process more effective and efficient.

1. Define scope

As the first step, narrow down through analytics what devices, platforms, and browsers your users are using.

2. Create a support matrix

A support matrix lists each feature and marks against it the level of support offered by each browser, platform, and device. It helps you understand and narrow down the scope of the cross-browser testing you’ll perform on the application.

3. Standardize coding practices

It’s recommended to utilize polyfills—code snippets that detect if a feature is supported by a browser, and if it isn’t, can add a custom implementation to cover that feature.

It’s advised not to use user-agent sniffing, which involves reading the browser’s user-agent to determine exact browser, platform, and device details and render conditional code.

4. Perform environment setup

Ensure that a staging or testing environment that very closely mimics your production setup is readily available to perform the testing.

5. Allow tooling access

Lastly, you must have access to tools such as cloud-based testing platforms and virtual device labs that run on actual physical devices to speed up the testing process while ensuring reliability and effectiveness.

How to perform cross-browser testing: A step-by-step guide

TL;DR: Cross-browser testing involves defining coverage, selecting tools, designing test cases, executing tests across browsers, and generating reports for debugging and improvement.

The following practical step-by-step process can help you perform cross-browser testing.

1. Create test coverage

Using the support matrix, the first step is to clearly identify and document which flows, features, pages (more specifically URLs), user flows, and journeys teams must test end-to-end on specific platforms, devices, and browsers.

Test coverage comprehensively dictates what teams need to test and where.

2. Select testing tools and automation frameworks

Often, an organization already has a stack of automation testing frameworks that they utilize for other forms of testing, like end-to-end testing, integration testing, etc., and it goes well with their tech stack.

For cross-browser testing, you additionally need to decide if the testing device will utilize emulators/simulators running on local machines, in-house physical device labs, or a hybrid setup such as a cloud testing platform.

3. Design test cases

Using the test coverage defined earlier, you can design actual test cases covering both functional and non-functional aspects of the application. These test cases are what will actually be run through manual tests or automation scripts.

4. Execute tests

You can run the automated test scripts and load the defined user journeys in multiple browsers, simulating that user flow.

For instance, if you’re testing checkout notifications, the script runs a checkout flow and validates whether a notification with the specified parameters triggers at the right time, on the right page, and so on.

These scripts also evaluate how specific visual elements appear on the notification UI, so they validate both functional and non-functional aspects of the checkout notification flow.

You can complement the automated tests with manual testing on various devices or utilize cloud-based testing tools to test various interactions, visual elements, and features using the test coverage checklist.

5. Create test report

After all the test cases have been executed and manual testing has been performed, you can create a test report for dev handover so that any inconsistencies, issues, warnings, and errors that arose during testing can be prioritized and fixed by the engineering team.

After a dev cycle, the process may be repeated once, and automated tests may be run on the CI/CD pipeline before the actual deployment to production.

What is cloud-based cross-browser testing?

TL;DR: Cloud-based testing platforms provide remote access to multiple browsers and real devices, enabling scalable cross-browser testing without maintaining physical device labs.

In addition to automation and integrations, you can also simplify manual cross-browser testing further through cloud-based browser testing.

Cloud-based browser testing happens on cloud platforms that have their own device infrastructure setup, where you can connect to virtual devices that map to real physical devices located in their data centers, enabling you to perform cross-browser testing without the need to actually own a device.

You can set up your own environment, record test logs, get access to a plethora of physical devices/browsers/platforms, and even run those devices in a different location.

As more devices emerge and browsers update, the coverage needed to ensure comprehensibility for cross-browser testing also increases.

What are the most essential features of a cross-browser testing tool?

TL;DR: Important features include broad browser coverage, real-device testing, automation integration, debugging capabilities, reporting tools, and strong security and compliance support.

The following features are important when evaluating a cross-browser testing tool:

1. Coverage

As more devices emerge and browsers update, the coverage needed to ensure comprehensibility for cross-browser testing also increases.

Hence, it’s important that the cross-browser testing tool has a wide catalog of devices and browsers available that are also frequently updated.

2. Real-device experience

Simulators and emulators provide a very limited experience compared to a real device, so teams prefer platforms that offer a high-fidelity equivalent of real physical devices and hardware.

3. Automation support

If a cross-browser testing platform offers native integration with the automation framework of your choice and stack, you could also run your automated tests on the platform itself, speeding up the testing process even further.

4. Debugging, reporting, and observability

Insights from testing, such as logs, metrics, screenshots, screen replays, etc., are essential to understanding how inconsistencies can be resolved.

5. Security and compliance support

Standard security practices, such as secure tunnels, data isolation, encryption, compliance certifications, etc., may be essential for organizations.

Top cross-browser testing challenges

TL;DR: Common challenges include expanding browser-device combinations, flaky automation tests, environment differences, and unpredictable behavior from third-party integrations.

There may be several recurring challenges that can render the entire process rather complex:

1. Broad scope

As browsers upgrade rapidly and new devices keep emerging in the market, an explosion of possible combinations of browser, device, and platform could broaden the scope of cross-browser testing considerably, making comprehensive coverage hard to manage.

2. Flaky tests

Even with foolproof automation scripts and robust testing features, nuances in web applications such as async behavior, variability in networks, and conditional UIs can cause false positives and negatives in the tests.

3. Environment differences

Practically, teams often struggle to replicate the exact same behavior of a production environment in a staging environment, which leads to issues that appear only in certain places and teams may miss them during testing.

4. Third-party dependencies

Analytics, integration with payment gateways, external widgets, etc., might behave differently and may be difficult to test completely.

Modernizing cross-browser testing with AI

TL;DR: AI-powered testing tools automate test creation, detect compatibility issues faster, and enable self-healing tests to improve efficiency in modern cross-browser testing workflows.

While traditional testing methods, cloud-based platforms, and automation simplify cross-browser testing, teams still face growing complexity.

Leveraging AI can help teams keep pace with modern application delivery. It also helps ensure consistent experiences across browsers and devices.

Tricentis offers AI-driven testing to simplify cross-browser testing, detecting compatibility and consistency issues faster and reducing manual testing efforts through its intelligent automation and AI-led workflows.

Tricentis can help you create tests with AI, reducing the amount of manual time used to write tests, create support matrices, and compile coverage reports.

Through self-healing tests and continuous optimization built into the platform, teams can deliver consistent user experiences across different browsers in a reliable manner.

Explore how AI-driven testing with Tricentis can help your teams scale cross-browser testing and accelerate their release cycles.

This post was written by Siddhant Varma. Siddhant is a full-stack JavaScript developer with expertise in front-end engineering. He’s worked with scaling multiple start-ups in India and has experience building products in the ed-tech and healthcare industries. Siddhant has a passion for teaching and a knack for writing. He’s also taught programming to many graduates, helping them become better future developers.