Complete guide on visual regression testing


Visual regression testing is like the superhero coming to save the day in today's software development scenario. It all comes down to ensuring that your app's appearance and experience remain flawless and unchanged regardless of how many upgrades you provide. The point is that angular visual regression testing goes above and beyond standard testing techniques. This ensures that everything works as intended.

visual regression testing

This kind of testing aids developers in maintaining the slick, polished appearance of their product. So, let us discover the various other perks these tests have to offer with the help of this comprehensive guide.

What is visual regression testing?

Visual regression testing is a commonly used software test to find inadvertent visual changes in a web application or user interface. To find any visual differences, screenshots or photographs of the application before and after a change or update are compared.

By automating this comparison process, developers and test companies may swiftly find and address visual issues that may arise from code modifications, browser updates, or other circumstances. Visual regression testing improves the overall user experience and preserves the integrity of the application's design by ensuring consistent visual appearance across various browsers, devices, and screen sizes.

Top regression testing tools used by developers

A vital component of software development is regression testing, which ensures that codebase modifications don't unintentionally create new regressions or issues. Various tools can aid regression testing, each with special features and functions.

Here are six tools for regression testing and a thorough explanation of their salient characteristics:


Mainly used for online application testing, Selenium is a well-liked open-source automation tool. It supports several browsers, including Chrome, Firefox, and Edge, and enables testers to build test scripts in various computer languages, including Java, Python, C#, and others.

The main component of Selenium, Selenium WebDriver, allows for interaction with web elements, which makes it appropriate for automated visual regression testing of applications.


A popular framework for unit testing Java programs is called JUnit. It is perfect for regression testing Java codebases since it offers assertions and annotations to define and validate test cases.

Developers can automate the execution of test cases with JUnit, which also offers comprehensive reporting on test results that include coverage metrics and pass/fail status.


TestNG is an additional Java-based testing framework that provides sophisticated functionality for regression testing, outperforming JUnit in certain areas. Testers can effectively plan and carry out tests thanks to TestNG's support for parameterized testing, data-driven testing, and test grouping. It has robust reporting features, such as HTML and XML reports, which make a thorough examination of test findings possible.


Postman is a flexible API testing tool that makes testing RESTful APIs easier. It is appropriate for regression testing of API endpoints since it provides an easy-to-use interface for generating and executing requests to the API.

Testers can specify variables and environments, group requests into collections, and use scripts to automate test execution with Postman. In order to guarantee the stability and dependability of backend services, Postman facilitates extensive validation of API answers.


For regression testing of desktop, online, and mobile apps, Ranorex is a commercial test automation tool. It offers a feature-rich integrated development environment (IDE) for developing automated tests with a graphical user interface and little programming experience.

Strong object recognition features provided by Ranorex enable testers to interact with UI elements on various platforms and in various technologies.

Apache JMeter

A popular open-source performance testing tool for web applications and services regression testing is Apache JMeter. Although JMeter is primarily designed for performance testing, functional regression testing can also be conducted.

Testers can use it to assess application response times under load, send HTTP queries, and mimic user interactions. JMeter is a tool that can be used to create intricate test scenarios and validate both functionality and performance.

Regression testing solutions come with various features and functionalities to meet different testing needs in different fields and technologies. The type of application, the testing goals, and the testing team's experience all play a role in selecting the best tool.

Are visual regression testing beneficial?

Visual regression testing is a useful tool in software development since it provides several benefits. Here are six specific benefits in further detail:

Comprehensive UI Testing

Visual regression testing makes it possible to test websites' or web applications' user interfaces (UI) thoroughly. It takes screenshots of the complete interface or selected parts, compares them to a baseline version, and looks for differences caused by updates or modifications to the code, such as layout shifts, typeface changes, or color variances.

Automatic Visual Defect Detection

Visual regression testing automates comparing visual aspects, in contrast to manual user interface testing, which can be laborious and prone to human error. Because of this automation, visual faults may be identified early on across various browsers, devices, and screen sizes, resulting in consistent user experiences across platforms.

Faster Feedback Loop

By promptly detecting visual regressions brought about by code modifications, visual regression testing helps to accelerate the feedback loop in the development lifecycle. Instant feedback on how changes affect the user interface enables developers to quickly address problems and stop regressions from going live.

Regression Prevention

Development teams can proactively stop regressions by incorporating visual regression testing into the continuous integration/continuous deployment (CI/CD) process. It is helpful to do visual regression tests in addition to functional and unit tests to preserve the integrity of the user interface and avoid unintentional visual changes being released into production.

Enhanced Collaboration

By giving developers, designers, and QA engineers a visual depiction of UI changes, visual regression testing fosters collaboration amongst these parties. Stakeholders readily review and approve visual modifications, guaranteeing compliance with design guidelines and user expectations. This cooperative strategy improves communication and lessens misinterpretations about UI modifications.

Better User Experience

Ultimately, visual regression testing improves the user experience by ensuring visual correctness and consistency. Teams can produce polished, end-user-friendly products that meet end-user expectations by identifying and resolving visual faults early in the development process. A consistent user interface (UI) across many platforms improves usability and fosters audience trust.

If you are not keen on spending much on this, then you can always opt for open source visual regression testing tools. But, may we say that this investment can reap massive benefits, in-terms of loyalty, customer satisfaction, increased customer retention, and more.

Types of visual regression testing

A vital component of software development is visual regression testing, ensuring that a website's or web application's visual design holds true during changes or iterations. The following list of six visual regression testing techniques:

Screenshot Comparison

To do a screenshot comparison, you need to take a snapshot of the user interface of an application or website both before and after modifications are made. Next, pixel by pixel, these screenshots are compared to find any discrepancies.

Automated technologies such as Puppeteer or Selenium WebDriver can be used to compare and take screenshots, detecting even the smallest visual anomalies.

DOM Comparison

This method compares the attributes and structure of the HTML elements that make up a webpage. This approach compares the underlying DOM structure before and after changes rather than images. You can use programs such as Wraith or PhantomCSS to take DOM snapshots, examine them, and identify any structural variations.

Layout testing

Layout testing analyzes how elements are positioned and arranged on a webpage or in an application interface. It ensures that components like buttons, text fields, and pictures are aligned properly and that their widths and lengths remain constant across viewports and browsers. Applitools Eyes and Galen Framework are two examples of tools that offer functionality for layout testing.

Responsive testing

Responsive testing aims to evaluate how an application interface or web page functions and looks on different screen sizes and devices. It guarantees a consistent user experience across computers, tablets, and smartphones by ensuring that the layout and design adjust fluidly to various resolutions, aspect ratios, and orientations.

Responsive testing is made easier by programs like CrossBrowserTesting and BrowserStack.

Visual AI Testing

This type of testing compares and analyzes how web pages or application interfaces look visually using machine learning algorithms. In contrast to conventional pixel-based comparison techniques, visual AI testing can intelligently identify visual differences by considering elements like layout modifications, font adjustments, and color variances.

Component-Based Testing

This type of testing concentrates on confirming that distinct UI modules or components inside a web application are consistent and functional. This method separates particular elements, like buttons, forms, or navigation menus, and tests them separately to make sure they function as intended in a variety of settings and scenarios, as opposed to testing entire pages.

Teams may efficiently find and fix visual discrepancies by integrating these different kinds of visual regression testing techniques into the software development lifecycle. This ensures the general quality and usability of their websites and online applications.


Visual regression testing is one of the most vital parts of contemporary software development. The many advantage of visual regression testing can help businesses to offer a seamless user experience to its end-users. Hence, in this article, we learned how it helps teams to identify inadvertent visual changes between iterations of a website or online application.

Visual regression testing helps to preserve brand integrity and user trust by automatically comparing screenshots of the application's user interface (UI) between iterations. This assures consistency in appearance and user experience.