Visual Regression Testing: Catch Every Change, Every Time

Transcript

Welcome everybody! Thank you so much for tuning in. My name is Christo Wilfred, and I’ve recently joined the team at BlogVault as a Growth Specialist. I’m thrilled to have all of you here and excited at the prospect of connecting with you.

Visual regression testing for WordPress

Today, we’re diving into visual regression testing, a critical yet often overlooked aspect of website management.

Before we begin, let’s set the stage. If you’ve ever updated a plugin or a theme only to find out later that it broke your site’s layout, this session is for you. If you manage multiple websites and constantly worry about updates causing design issues, you’re in the right place.

Today, we’ll explore what causes updates to break sites, what visual regression testing is, and why it’s essential for maintaining a flawless user experience. This session is designed to be informative and practical, with actionable takeaways. By the end, you’ll have a clear understanding of how to prevent visual bugs from affecting your website and your users.

We also have a Q&A session towards the end of the presentation. You can ask us anything. If you have any immediate questions, please drop them in the chat window, and we’ll surely get to them.

Why sites break after an update

Websites break all the time for many reasons, and the cause isn’t always immediately obvious.

Even if a site looks fine initially, hidden issues can surface later, causing broken functionality, visual glitches, or even downtime. There are three major reasons why this happens:

1. JavaScript conflicts: Modern websites rely heavily on JavaScript for interactivity, animations, and user actions. However, when multiple scripts run simultaneously—whether from plugins, themes, or custom code—they can interfere with each other. This can break core functions like navigation menus, checkout buttons, or pop-ups. A single conflicting line of code can make a site unusable, leading to frustrated users and lost business.
2. Third-party failures: Most websites integrate with external services for key functionalities such as payment gateways, live chat widgets, or marketing automation tools. If any of these services go down, experience slowdowns, or update their APIs without backward compatibility, your site may display errors, lose data, or completely stop working. For example, if a payment gateway fails, customers won’t be able to make purchases, directly impacting your revenue.
3. Incorrect update rollouts: Updates are crucial for security and performance, but they must be implemented carefully. Rolling out an update without proper testing can break site layouts, disrupt user workflows, or even take an entire website offline. Common issues include CSS breaking after a theme update, plugins losing compatibility, or database migrations going wrong. A structured testing and backup process is essential before applying any updates.

By understanding these risks, you can take proactive steps such as using staging environments, automated testing, and reliable backup solutions to keep your site running smoothly.

The impact of visual breaks

Now, let’s start with the big picture: why do visual issues matter so much? When a user visits your website, the experience isn’t just about speed or functionality. How your site looks directly impacts their perception of your brand. If something is visually off—text overlapping, buttons disappearing, images misaligned—it immediately lowers trust.

Consider an online store: if a customer lands on a checkout page where the “Buy Now” button is misaligned or hidden due to a CSS error, they may assume that the website is unreliable and abandon their purchase. The challenge is that these issues often go unnoticed until it’s too late—until a user complains, sales drop, or engagement falls.

VR testing for dynamic sites: The WP Remote advantage

Screenshot-based testing sounds like a straightforward solution—take a picture before and after an update and compare them to spot the differences.

However, in reality, it’s far more complex. Websites are dynamic, with constantly changing elements that vary based on user interaction, real-time data, or external factors. This makes it nearly impossible to capture consistent screenshots without running into inconsistencies. Traditional visual testing tools often struggle to account for these changes, leading to unreliable results, false positives, and overlooked critical issues.

Let’s break down why screenshot-based testing is so difficult.

Websites aren’t static; they are built with dynamic elements that update and change based on user interaction or external data.

For example, elements like sliders, pop-ups, ads, and JavaScript can move, fade, or refresh, making it hard to capture a consistent screenshot. If an ad loads differently each time, it can trigger false alerts.

These constantly changing visuals create inconsistencies in screenshots, and most testing tools cannot handle these changes properly, leading to inaccurate comparisons.

What exactly is visual regression testing or VRT? In simple terms, it’s an automated process that takes a snapshot of your website before and after an update and highlights any key differences between the two.

Imagine you’re cleaning your room: you take a picture before and after, then compare them to see if anything was unintentionally moved, missing, or out of place. Visual regression testing does the same for websites. It ensures that every element remains exactly where it should be after an update. This process allows us to confidently apply updates without accidentally breaking site layouts, shifting elements, or altering design consistency.

When you update a website, how do you know that something has visually broken?

As mentioned earlier, it is by comparing before-and-after screenshots. Visual regression testing works by automating this process, ensuring that nothing is missed. Now, you might be thinking: why not just check manually? The problem is, websites have thousands of elements, and even big changes can go unnoticed.

No human can, or should, review every page and every detail after every update; it’s simply not practical. This is why automation is key.

A good visual regression tool like WP Remote does this checking for you—accurately, consistently, and in a fraction of the time it would take to do manually. It helps agencies and site owners avoid expensive mistakes and ensures their site always looks the way it should.

Increasing the difference threshold is never the answer

Since capturing reliable screenshots is so difficult, most testing tools take a shortcut: they simply ignore changes below 10%. But small differences can have massive consequences. A menu button disappearing may be a tiny visual change, but if users can’t navigate, your site is broken. A CTA button changing color—a shift from green to gray—could completely alter conversions. Let’s have a look at an example.

Now, as you can see on the screen, post-update the stars on the rating module of this website went from gold to black. A five-star rating disappeared—poof, just like that. Because the gold stars turned to black, it looks like a zero-star rating, leading to a massive loss of credibility and sales. By the way, this isn’t just a random example; it’s a screenshot from one of our actual customers’ websites. They hadn’t noticed this change until WP Remote notified them and pointed it out.

I want to take a minute to talk about a common issue in visual regression testing: false positives.

Getting false positives is one of the biggest challenges in visual regression testing. If a tool keeps raising alarms over non-issues, users eventually stop trusting it. This is called alert fatigue, where people start ignoring warnings because they assume they are incorrect. Unfortunately, most tools get this completely wrong. In fact, most of the issues they report are false positives, meaning developers waste time investigating problems that don’t actually exist. This makes traditional VRT solutions unreliable in real-world use.

At WP Remote, we knew this was a critical problem to solve. We built our system differently. Eight out of ten times when we flag an issue, it’s a real problem—a massive improvement over traditional tools. But we’re not stopping there. Our goal is nothing less than ten out of ten accuracy. We’ve developed proprietary algorithms that handle dynamic elements of all kinds and intelligently filter out false positives, ensuring that every flagged change truly needs attention. This means you can trust our alerts, saving time, reducing frustration, and making visual regression testing a seamless part of your workflow.

Real-world cases

Let’s look at a real-world example. One of our customers, a WordPress agency owner, integrated WP Remote’s visual regression testing and completely transformed their workflow. Instead of spending hours manually checking sites post-update, our VRT engine now catches issues instantly and alerts them, ensuring that every update is seamless and error-free. This shift has not only saved them countless hours and dollars but has also strengthened their clients’ trust in their service. As they put it, updates with WP Remote are a superpower, not a risk. This mindset shift is what allows agencies to confidently manage multiple websites without the fear of unexpected visual issues.

All right, let’s take a look at WP Remote in action. I’m going to show you some real-world examples—before-and-after screenshots from our existing clients. These are actual visual changes that WP Remote has detected. As we go through them, take a moment to see what you can spot with the human eye. Some changes might be obvious; others will be nearly impossible to catch manually. This is exactly why automated visual regression testing is so critical.

Let’s dive in. Take a look at this page—it’s a well-designed, premium-looking website. There are multiple buttons, clear calls to action, and a polished, structured layout. Importantly, there are no obvious dynamic elements—nothing constantly shifting, no sliders or animations that could make comparisons difficult.

Now, imagine you’re manually testing for visual changes. Take a moment to scan the page the way you would in a real scenario: look at the buttons, the text alignment, and the layout. At first glance, everything looks perfect, right? Let’s see what happens after an update.

Now, here’s the “after” version of the page. At first glance, it might look almost identical to the previous version, and that’s exactly what makes VRT so tricky. When changes are subtle, they can be incredibly easy to miss. Let me ask you, were you able to spot any differences? It might seem like a small detail, but did you notice that the left arrow below the search bar is no longer aligned vertically?

Why does this matter? In the context of a premium high-trust website, even a tiny misalignment can make a difference. Imagine a user landing on this page and feeling that something’s off. Even if they can’t consciously identify what’s wrong, that little inconsistency can create a subconscious sense of mistrust, and in a world where trust drives conversions, that’s a serious problem.

But that’s not all. WP Remote didn’t just catch the button shift; it identified other elements that were unintentionally changed as well. These are the types of subtle issues that manual testing would miss entirely. What’s powerful here is that WP Remote doesn’t just tell you something’s changed; it pinpoints exactly what’s changed, so you can quickly assess whether it’s important. This is what sets true visual regression testing apart from basic screenshot comparisons.

Instead of relying on the human eye, which can easily miss small but critical changes, WP Remote ensures that nothing slips through the cracks. Now, let’s take a look at another example.

Unlike the previous example, this website is much more design-heavy, with high-res images being a key feature of the site. You’d think spotting visual changes manually would be easier, right? If an issue were to appear, it surely would stand out right away. That’s the assumption many developers and QA testers make. Now, let’s put that assumption to the test.

Take a few seconds to scan this page and get familiar with how it looks. All right, now let’s see what happens after an update.

Here’s the “after” version of the same page. This time, it’s a little easier to spot what’s changed—the font has clearly changed. It’s one of the most noticeable shifts to the human eye. But here’s the thing: even though it’s obvious, it still causes a problem. Why?

Because typography plays a huge role in branding and trust for customers. Bad typography can lead to distrust. If they notice an unintended font change, they might subconsciously wonder if the site is hacked or if it’s even the official website. That tiny moment of hesitation could cause businesses to lose conversions, signups, and sales. This is why even seemingly minor visual changes matter.

Now, let’s see how WP Remote ensures you never miss an issue like this. WP Remote simplifies visual regression testing by instantly highlighting changes—no manual scanning needed. Rather than just detecting a change, it makes it actionable. If a font shifts, your team can quickly confirm if it’s intentional or roll it back before it affects customers.

Let’s face it; most websites have multiple dynamic elements—constantly shifting ads, sliders, carousels, and more. So, how does our VRT handle all of that? Well, let me show you.

This is a test website that we built to test out our VRT. From the get-go, you can see constantly shifting dynamic elements, for example, a clock. As you can see, it’s an image-heavy website with some e-commerce elements, carousels, and forms.

Now, let’s observe how competing VRT tools handle this. You’ll see that it’s very challenging, especially in the context of a dynamic website like this, to capture all the elements. Some images might be missing, or certain sections overlooked. These tools can fail to properly manage the dynamic elements, resulting in alert fatigue where unnecessary notifications are sent frequently.

Now, let’s look at WP Remote’s dashboard. Our VRT algorithm is designed to be smart and context-aware. It doesn’t just flag every little change; it understands which changes actually matter. Take this example—the clock updates in real time, but our system correctly identifies that this is an expected change, not a website-breaking issue.

Not only that, our screenshot quality is exponentially better than that of other tools. We capture everything without missing any element, image, or section, ensuring the most accurate comparisons possible.

Dynamic elements like user reviews, which update regularly, might trigger false errors in other tools, but WP Remote knows better. By filtering out these expected changes, we ensure you get alerted only for real issues so you can focus on what actually needs fixing and not false alarms.

The future of visual regression testing is exciting. We are at the forefront of some great advancements in this area. AI and machine learning are making automated testing tools smarter, allowing them to learn what changes are normal and what’s actually a problem. Expect more precise detections and better filtering of false positives, helping testers focus only on real issues and making debugging faster.

As website complexity grows, the need for accurate automated visual testing will only increase, and I’m glad to announce that we are very much at the forefront of these advancements.

We’d love to hear from you! Let’s open up the floor for some questions. My team is ready. If you have a question, please raise your hand using the react button or drop a message in the chat box. In case we don’t get to your question, don’t worry—we will ensure that we reach out to you and help with any query you have.

Here’s the big takeaway: a very small percentage of all updates introduce real visual issues. That might not sound like much, but over time it adds up. With regular updates—plugins, themes, browsers—that 1% compounds, leading to at least four major visual issues per year on an average website. And these issues often go unnoticed until they start hurting conversions and user experience.

What happens when they slip through?

A missing CTA button means lost sales, a broken pricing table confuses buyers, and a shifted navigation menu frustrates users. These aren’t minor glitches—they impact trust and revenue. That’s why WP Remote is essential. It doesn’t just detect issues; it prevents disasters by giving you instant visibility and control over every change before it affects your business.

That brings us to the end of today’s session. I hope this webinar gave you valuable insights into visual regression testing. A huge thank you to the team and to everyone attending and engaging with us today. If you have any more questions, feel free to reach out. You can contact me at sales@blogvault.net or visit us at www.blogvault.net. I’d love to continue this conversation and hear your thoughts.

Once again, thanks for your time. It’s been great hosting all of you, and I look forward to staying in touch and seeing you in future webinars. Have a great day!

Q&A

The visual regression testing is built into the safe update, correct? That’s got it. Okay, this might be more specific to me and our situation, but I used to do the safe updates. However, it kept increasing the load on our servers and would occasionally take them down. For months now, I’ve just done the quick updates and hoped everything would be okay. I check things afterward because I felt the safe updates added too much load. Is that something you’ve seen with other people, or do you think it might be specific to our server configuration?

Actually, that’s something I’d like to investigate further. Server load shouldn’t just happen without cause. If you can run any safe management and drop us an email, we can check our logs. We may need logs from you as well to pinpoint what’s happening. This will give me a better understanding of what’s causing the load on your end. It’s definitely not the visual regression testing causing the load, but possibly the entire safe update process.

Got it. So that’s something we can check. With visual regression, we only send two to three requests at max, so that shouldn’t cause any load on your website.

Will there be a tool for functionality changes?

I’m assuming you’re asking if we’re going to make a tool for this. Right now, it’s integrated into our WP Remote dashboard. We are not planning to make it a separate tool at the moment. But we can consider it for the future.

I regularly use your visual regression testing. We do a few hundred updates a day, so we generally use the safe update option unless we’ve recently done a sync. For the most part, when things come back as a perfect match, it’s great. I haven’t seen any major issues—it’s very accurate. Occasionally, I notice some padding or thickness changes that don’t seem legitimate, but it doesn’t happen often. So maybe that’s the two out of ten false positives.

One question I have is: is there a way to make switching which page is selected for visual regression testing a bit easier? I know you can do it in the settings, which takes a few clicks, but is there a way to identify a new page or post for testing specifically?

We’ve discussed this internally. We’re considering changes to identify new or important pages—like a new WooCommerce page—and how to implement visual detection for those with your update process. We’re planning this, but it’ll take time to implement. We haven’t forgotten about it.

I’ve used Visual Regression Testing on some of my clients’ websites, and it’s been working fine. I’d be happy to see a future settings page that tests as a specific logged-in user.

That’s great feedback. Thank you! Use cases like this are invaluable. When building the tool, there can be some bias, and your feedback helps us understand what clients and agencies need. We can use this to improve our features. Thank you so much, for this feedback.

Further resources

Presenter