Visual Testing

Ensure pixel-perfect accuracy, detect UI inconsistencies, and optimize user experience across devices using Visual Testing by Percy
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What is Visual Testing?

Visual testing is a software testing technique that evaluates the visual appearance and behavior of a software application’s user interface (UI). Visual testing aims to verify that the application’s visual elements, like colors, images, fonts, and layouts, are displayed correctly and consistently across different devices, operating systems, and browsers.

Visual Testing

Why is Visual Testing Important?

To highlight the necessity of visual testing, let’s look at a case of a newly launched online shopping platform. Aimed at offering everything from apparel to snacks, the platform initially passed all automated tests. Yet, when it went live, a major flaw was discovered. The ‘Checkout’ button was inaccessible to mobile browser users and was hidden behind a text box due to limited screen space.

This oversight, not detected during testing, became a major obstacle in user experience, underscoring the importance of Visual Testing in app and website development.

As users take just 50 milliseconds ( 0.05 seconds) to decide whether to stay or leave a website. Considering the usage shift towards smartphones and tablets over desktops, apps and websites must provide superior experiences on various mobile devices.

Here are some stats to prove:

Visual Testing-stats

Diverse browsers, devices, and screen resolutions can cause inconsistent user experiences, including visual glitches, layout problems, and increased loading times, leading to higher bounce rates and reduced engagement.

Here are some reasons why you should perform Visual Testing

  • Manual testing is time-consuming and inconsistent: Manual visual testing often leads to inaccuracies due to human error and inconsistency. It’s a time-intensive process, particularly challenging in complex applications, and can struggle to cover all scenarios, leading to overlooked defects. Additionally, reproducing issues for further analysis can be difficult. This approach also demands substantial resources, making it a costly option.
  • Functional tests are not meant to assess visual aspects: While functional testing plays a pivotal role in verifying the operational aspects of a software application, it often overlooks a crucial component – the visual experience. Functional tests are designed to ensure that various elements of the software perform as intended, but they typically do not encompass the visual aspects that are vital from a user’s perspective. It includes detecting issues with alignment, pixel accuracy, rendering, layout, overlapping elements, font changes, and responsive design.
  • Responsive tests are complex: As the range of devices and screen sizes expands, applications need to adapt responsively. Maintaining a uniform visual appearance across various devices and resolutions presents a significant and complex challenge.

What can Teams achieve with Visual Testing?

Visual testing offers the following benefits:

teams -Visual Testing

  • UI/UX Consistency Across Devices and Screens

Automated Visual Testing continuously checks for visual stability, regardless of the changes being made. Whether it’s CSS modifications or updating dependencies, this testing ensures the user interface remains unchanged. It covers the entire UI spectrum, from key functions to error pages, across various browsers and screen sizes, offering broad and reliable coverage.

  • Navigate the Blind Spots in QA with Visual Regression Testing

Visual regression tests play a crucial role in preventing visual bugs from reaching production and negatively impacting user experiences. Although functional and manual testing are effective in identifying many bugs, they frequently miss visual discrepancies. 

Automated Visual Testing provides a solution, enabling consistent regression testing by comparing screenshots across devices and resolutions. This helps QA teams spot minor discrepancies in the user interface, indicating potential bugs or changes.

  • Increased Productivity and Scalability

Automated Visual Testing surpasses human precision, operates faster, and is more cost-effective. Its scalable, low-cost nature benefits not just developers but also designers, product managers, and marketers. It’s a valuable tool for diverse teams, streamlining design verification, information sharing, and UI updates.

  • Getting Complete Code Refactoring Confidence

Coding stress often arises from uncertainty about causing errors or not fully understanding design implementations. This leads to time-consuming manual searches for visual bugs and writing tests to prevent regressions. Visual Testing automates this, allowing for confident deployments with assurance that the app looks perfect across different browsers and screen sizes.

Who uses Visual Testing?

Here are some of the key roles and responsibilities of individuals involved in Visual Testing to ensure a comprehensive approach to quality assurance.

  • QA Experts: Utilize their expertise to thoroughly inspect and validate visual aspects, ensuring design fidelity.
  • Manual Testers: Focus on the user interface’s visual quality, pinpointing any discrepancies in design elements.
  • Front-End Testers: Test for visual consistency and responsiveness across diverse devices and browsers.
  • Designers: Confirm that the application faithfully translates their design concepts and adheres to brand guidelines for a cohesive user experience.

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Visual Testing vs. Functional Testing

Visual Testing and Functional Testing are two essential approaches to software quality assurance, each with its distinct focus and advantages. 

Functional testing focuses on validating the software’s functionality, ensuring that each feature works according to the specified requirements.

However, functional testing will not completely help in identifying visual changes across different browsers or devices. It will not help you identify pixel-by-pixel differences, alignment shifts, page layout issues, rendering problems, element overlap, responsive layout, font differences, color differences etc.

Fortunately, visual testing can solve these problems. Visual testing ensures the consistent and accurate presentation of the application’s visual elements, such as layout and graphics, across various devices, operating systems, and web browsers.

Listed below is a detailed comparison of visual testing vs functional testing.

ParametersVisual TestingFunctional Testing
DefinitionVerifies that the application’s visual elements are displayed correctly and consistently across different devices, operating systems, and browsers.Ensures the application’s features and functionalities operate as expected.
FocusEmphasizes the appearance and behavior UI of the application.Centers on functionality of the software, focusing on business logic.
Testing scopeValuable for maintaining web page consistency.Essential for validating critical workflows.
Code EfficiencyEmphasizes writing less code for functional validation.Requires eliminating all codes related to visual validation at the time of implementing automated visual testing.
ConsistencyGuarantees cross-browser and cross-device consistency in the visual output.Might succeed on one browser/device, but lacks assurance of consistent visual output across different platforms.
CollaborationEnhances collaboration through user- friendly screenshots, easily understood by non-technical team members.Being technical, it may lead to discrepancies in understanding among team members.
Test CoverageProvides broad coverage of application appearance with relatively fewer test cases.Demands more test cases for functional coverage, with requirements growing exponentially for a broader scope.
Bug VisibilityVisual bugs are visible to 100% of users, allowing for immediate feedback.Functional bugs are only seen by users who encounter the specific functional issue.

Types of Visual Testing

Manual Visual Testing

Manual visual testing combines human inspection and verification to assess a software application or website’s visual aspects, to ensure compliance with design and functional requirements. 

Challenges in Manual Visual Testing:

  • Human error
  • Time-consuming
  • Inconsistency
  • Difficulty in reproducing issues
  • Limited scope
  • Costly

Automated Visual Testing

Automated visual testing employs specialized software tools to automatically validate a software application or website’s visual appearance and behavior. Unlike manual testing by humans, automated visual testing utilizes computer programs to simulate user actions and assess visual elements, comparing expected and actual appearances to identify discrepancies and defects, including text, images, colors, and layout.

This approach streamlines testing, reduces human error, enhances consistency, and expands test coverage, addressing challenges associated with manual visual testing while identifying defects that might be overlooked in manual processes.

Learn More about Percy

Why choose Percy for Visual Testing?

Percy is an all-in-one visual testing and review platform. It helps teams automate their visual testing process to catch visual bugs and gain insights into UI changes on each commit. 

Percy’s Visual Engine helps you save hours spent hunting for visual bugs by highlighting the most important changes. With Percy, you can:

  • Ship with confidence

Percy helps you increase visual coverage across your entire Ul. Add visual testing to any page by adding a simple Percy command. With automated visual testing, you can not only review visual changes with every commit but also have complete confidence that the rest of your UI has remained unchanged.

  • Integrate visual testing with your existing workflow

Add visual testing to any web app, static site, style guide, or component library. Percy also integrates with CI services such as Github, Gitlab, and Bitbucket, among others. Percy even lets you build your own SDKs to integrate with Percy using Percy Agent. Reach out to us if you don’t see your technology here.

  • Perform cross-browser visual testing on real desktop and mobile devices 

Switch between desktop and mobile browsers with a single click and eliminate cross-browser and cross-platform visual bugs. With Percy, you can review visual changes on the latest versions of Firefox, Chrome, Edge, and Safari. You can also test across as many responsive breakpoint widths as you want to deliver a pixel-perfect UI across multiple screen sizes.

  • Discuss changes and collaborate

Add comments and tag your team to highlight, resolve, and discuss changes while reviewing visual inconsistencies. Percy adds visual reviews alongside your existing code review process to minimize the risk of shipping visual bugs. Percy also keeps your teams updated with pull status updates, comments, and notifications.

  • Dynamic data handling

Percy’s proprietary snapshot stabilization technology automatically freezes animations to minimize false positives. You can also ignore specific areas of your page using percy-specific-css.

  • Leveraging existing test suites

Percy integrates seamlessly into your existing CI/CD workflow and supports popular test automation frameworks (like Selenium, Cypress, Playwright, Puppeteer etc) , languages (like Puthon, ruby, Java, .Net etc), tools, and workflow integrations. 

Try Visual Testing With Percy.

How to Perform Visual Testing using Percy?

Percy helps teams automate visual testing. It captures screenshots, compares them against the baseline, and highlights visual changes. With increased visual coverage, teams can deploy code changes with confidence with every commit.

Let’s see how to perform visual testing using Percy?

15 -Visual Testing Process

  • Login to Percy.
  • Create a project.
  • Set environment variables
  • Integrate the Percy SDK into your web application. It supports various programming languages and testing frameworks, so you can choose the one that suits your project. Refer to this guide to learn more
  • Generate first build
  • Generate second build
  • You see the comparison between the first and the second builds.


With features like Zero Code Change Integration, Rapid Build Execution, and the ability to test mobile native apps, Percy enhances collaboration and productivity.

21 - Canva Percy

Canva, uses BrowserStack to perform visual testing. By automating the process of identifying discrepancies in the user interface, Percy saves time and resources and enhances accuracy in bug detection.

Incorporate Percy into your testing workflow and gain full visual confidence, leading to the creation of visually flawless and user-friendly products. Join the ranks of developers who trust Percy for impeccable visual quality.

Try Visual Testing With Percy

Need Visual Testing for your Website?

Try BrowserStack Percy to run Visual Tests and check if the Wesbite appears consistent across different real browsers and devices using Visual Diff feature