A Guide to Visual Regression Testing and Different Tools


In this blog, we will cover everything related to the visual regression testing tools that you need to automate your testing efforts. Applitools, Screener, and other commercial visual testing tools are also reviewed.

Before jumping on the tools, let’s first understand what is automated visual regression testing?

Automated Visual Regression Testing

Automated visual regression testing may sound complicated at first, but the premise is straightforward. First, you have a mental image of how your user interface (UI) should seem to the user, and you run tests on the current UI to check if any “regression” has occurred.

mobile app automation

Visual regression testing isn’t as easy to automate as we’d like, and while the goal is to detect faults in the layout, deciding what variations are acceptable typically requires a person. For example, many websites with graphical functionality, such as drop-down menus, clickable charts, and interactive dashboards, can have their contents entirely thrown off by a slight change in pixels. 

Simultaneously, because most of the pixels on that page are white, sites with a more straightforward design (like the Google homepage) will seem pretty much the same regardless of visual defects.

Despite the inescapable human meddling, there are various tools for testing platforms such as Selenium, PhantomJS, and XULRunner that can automate visual testing to some extent. 

For example, Wraith, WebdriverCSS, Needle, Huxley, and others are among the programs that use a snapshot comparison engine to take screenshots and compare them in intervals.

Read also: Regression Testing: Complete Guide

Automated Visual Regression Testing Tools and Frameworks

There are many tools for automated visual testing in the market. Some of these tools are free to use, while others are for a fee. Most of the tools work the same way, although they follow a distinct process depending on the intended audience.

There are two sorts of visual testing frameworks for front-end developers. To begin, you’ll need a test runner that allows you to develop and run tests. To mimic user interactions, you’ll also need a browser automation framework. Visual test code is the combined name for these two frameworks.

Developers use frameworks to construct code that mimics real-world user behaviors such as inputting text or clicking buttons. For example, there are commands in the test code to snap screenshots at critical stages. An initial set of screenshots is taken when the test is run for the first time.

These screenshots serve as a benchmark against which any modifications can be measured. The developer runs the code in the background once the baseline is set. When a change is discovered, a screenshot of it is taken.

This screenshot is compared to the baseline screenshot by the test runner. The test fails, and it reports a visual bug if any discrepancies between the photos are discovered.

A report is created automatically once the entire test code has been executed. A human tester thoroughly reviews this report to check all screenshot images that differ from the baseline photographs. 

Moreover, a different picture is generated by some technologies to show the difference between the actual and expected screenshot.

If the discrepancy is due to a bug, the developer can repair the program. If the difference is due to a required change in the application’s UI, the developer examines the screenshot and adjusts the baseline screenshot to ensure that future tests pass.

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What To Look For While Choosing Visual Regression Testing Tools?

We’ll assume you’re already performing regression testing, whether you’re manually browsing through your app or using an automated tool.

If you’re thinking about adding a visual regression testing tool to your arsenal, there are a few things to look for to see if it’ll satisfy your requirements.

#01 Coding Skills You Need

There are two types of automated testing tools available:

  • Testing frameworks to assist developers in writing coded test scripts and 
  • no-code tools that allow anyone to generate tests using a drag-and-drop interface or a record-and-playback plugin.

These two categories also include visual regression testing tools. For example, if your QA team lacks programmers, you’ll want to look for a no-code solution.

#02 Filteration Of False Positive

When a visual regression testing tool finds visual regressions on the front end that influence the user experience, it must reliably cause a failure while disregarding visual changes that don’t issue.

It appears simple, but it is rather challenging to execute. Most tools, particularly open-source options, compare images of the entire UI and mark every change, making them too sensitive for most users.

#03 Does It Require Any Add-ons?

A few visual testing tools are one-stop testing solutions, which may be used to build, run, and update tests. However, they only provide visual validation; hence they should be used with another regression testing solution. 

Other products are simply plug-ins for your existing automation framework that add visual assurance. They commonly accomplish this by inserting a snapshot into an automated test script.

On the other hand, TestGrid.io is a one-stop solution for automating both traditional and visual regression testing. (However, I’ll get to that later.)

#04 Open-Source Or Commercial

There are some free, open-source tools that you’ll never have to pay for, but they usually don’t come with customer service, require programming knowledge to operate, and are more limited in what they can do.

When it comes to commercial tools, several include pricing tiers that push you to upgrade to a far more expensive level once you’ve used up your beginner plan. 

Furthermore, specific tools bind you to long-term agreements. An ideal tool will allow you to pay for only the testing you require, with the ability to scale down or scale up as your needs change.

Read Also: Regression Testing: Complete Guide

Commercial Visual Regression Testing Tools

#01 Percy Visual Testing

Percy is one of the most sophisticated visual testing tools available. You can use it to integrate, run, and review visual tests. Integration can be accomplished using test automation frameworks, continuous integration, delivery services, or directly through your application.

We can begin performing the required visual tests on the apps and components following integration. 

The Percy tool extracts UI screenshots across many browsers and responsive widths when a visual test is started. It then compares your UI against a baseline pixel by pixel and finds any relevant visible changes.

You can check the screenshots for any visual concerns once they’ve been produced.

This tool’s pixel-by-pixel and responsive diffs provide excellent visual coverage. The snapshot stabilization option also helps to reduce false positives.

This is a paid service, but it does provide a free trial version.

#02 Applitools

It’s one of the most widely used commercial frameworks for visual regression testing and automated visual testing. This tool gives you a cognitive vision driven by AI. It employs artificial intelligence to help you with visual testing and monitoring from start to finish.

You can test hundreds of UI components across all platforms and configurations with Applitools without writing any code or with very little code. In addition, it supports over 40 different testing frameworks and languages.

It also helps with DevOps by allowing you to easily integrate visual test cases into the CI/CD workflow. You may also use this tool to build bespoke graphic reports.

Some of the world’s most well-known organizations, like Sony, SAP, MasterCard, and PayPal, use this framework. It also has a lot of great feedback from customers.

Starter, Enterprise Public Cloud, and Enterprise Dedicated Cloud are the three versions of this framework offered by the manufacturer.


#03 Screener.io

This cloud-based automated testing solution allows you to record and run tests in real-time. Test flows can be readily automated without the need for coding. It detects UI discrepancies across multiple platforms automatically. It also aids in the testing of storytelling components.

Combining visual and functional testing in the same test run allows you to increase total test coverage. For example, Microsoft, Yammer, Uber, and more companies use screener.io.

#04 Crossbrowsertesting Visual Testing

You may easily filter your test results to determine which ones have aesthetic flaws. You can also go straight to a live test and debug or fix the visual flaws. This software includes a local connection tool to test local and development environments.

Once you’ve completed a screenshot test for visual regression testing, you can schedule it on a daily, weekly, or monthly basis. Notifications of test results will also be sent out by the tool.

This program contains an automated comparison engine that allows you to take automatic screenshots of the same page in different configurations. You can then choose a baseline browser and compare the highlighted layout variations.

It also has sophisticated features to help you make your exam more effective. Basic authentication, Login profile, Selenium script, Screenshot delay, Send emails, Hide fixed items, and so on are some available choices.

#05 Endtest

This UI testing platform uses machine learning to allow codeless automated testing. It enables you to develop automated tests quickly, save them, and run them in the cloud. In addition, they provide a Chrome addon that allows you to record the tests.

Generate random test data, advanced assertion, automatic backups, geolocation, live videos, screenshot comparison, and more capabilities are included in this program.


Visual regression testing is as vital as functional testing if you want a pleasant user experience. However, a range of tests can be covered when visual and functional testing is coupled.

This testing can be done with various open-source and commercial tools and frameworks. We have also discussed the most valuable tools. Those visual regression testing tools can help you completely automate your testing efforts.

Click here to know more about TestGrid.io and also, to read more articles, you can head over to our blog section.

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