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The ultimate guide to A/B testing in Webflow

Follow this guide for A/B testing in Webflow to help you test different versions of your site and discover the best performing ones to improve conversions.

What is A/B testing?

A/B testing is an experimentation process that you run on your website to determine which of two or more assets (A vs. B) performs better, like specific elements, copy, design or entire pages.

This test simply tells you which variation works better for your audience based on statistical analysis. A/B testing eliminates the guessing - by running these tests on your website, you can make data-backed decisions to optimize properly and increase conversions. 

Disclaimer: In this A/B testing guide for Webflow, we recommend that you use Optibase because it integrates natively with Webflow. But no matter what tool you choose for testing, this guide will still help you set up tests on your website.


How does A/B testing work?

An A/B test or split test is an experiment where you show two test variants to users randomly. With statistical analysis, the tool determines which variation performs better depending on your conversion goal. 

There are a few ways to run a test on your website, depending on what you want to compare. 

A/B test:

  • In an A/B test, you change just one small thing on your site. This could be a button, parts of text, an image or a form. 
  • For example, you might make the button a different color or make the text larger. 
  • When people visit your site, they randomly see one of these variants. 
  • The goal is to see which change makes people do an action, like buying something or signing up. These are conversions and they determine which variant performs better. 

Split test:

  • A split test is more extensive. Here you change a whole page. 
  • You might make bigger changes, like the layout, the colors or even where certain elements are placed. 
  • Site visitors are randomly directed to one of these whole page variants. 
  • The goal here is to see which big changes lead people to do important actions more often, like clicking a button or signing up. These are called conversions and they determine which variant performs better. 

Multivariate test:

  • A multivariate test is the most extensive, because you test more than two variants. 
  • For example, here you can test combinations of headlines, descriptions and product videos. 
  • Site visitors are then randomly directed to one of these page variants. 
  • The goal here is to determine which type works best for your audience. 
  • The big downside of multivariate testing is that you need an enormous amount of traffic for results to be meaningful, so it’s not recommended if you’re just starting out. 

By showing these tests to your website visitors, you save a lot of time and resources. And if you’re not A/B testing your website, you’re surely losing out on a lot of potential business revenue. 

This is how an A/B test works in the most simplest form:

  • Randomly divide website traffic into two or more groups. 
  • Show these groups different variations for a set period of time. 
  • Compare the performance of each variation in terms of conversions. 
  • Analyze the results to determine if the changes are worth implementing. 

The benefits of A/B testing

There are many benefits for businesses that are implementing A/B testing. Let’s break it down:

Increased conversions

The cost of acquiring quality traffic on your site is huge. A/B testing lets you make the most of your existing traffic without having to spend additional money on acquiring new traffic. 

By testing different variations and showing them to your website visitors, you can optimize continuously to improve the user experience and increase conversion rate. Sometimes even the smallest changes on your website can give you high ROI (for example changing the CTA). 

Solve visitor pain points

Visitors end up on your website to achieve a specific goal. It may be to learn more about your product or service, buy something, sign up or to simply browse. But whatever the visitor’s goal may be, they might face some common pain points while doing that. It can be a copy that’s too complex or a CTA button that’s hard to find. 

Not being able to complete their goals leads to bad user experience, directly impacting your conversion rates. If you put that to the test with two different variations, you can quickly fix their pain points before it’s too late. 

Reduce bounce rate

One of the most important metrics to track on your website is the bounce rate. It can come from a lot of different things, like too many options to choose from, confusing navigation, complex copy, hard to find CTA buttons, website not being what they expected it to be, and so on. 

Since different websites address different audiences, there is no ultimate solution for all to reduce bounce rates. But running an A/B test can be beneficial. With A/B testing, you can test multiple different variations on your site until you find the best possible version. This not only helps you find traction and fix visitor pain points, but also helps improve their overall experience. If your site visitors are happy, they’ll more likely convert into a paying customer. 

Make low-risk changes

By testing your website with A/B tests, you can make minor changes instead of getting the entire page redesigned - which would be usually the case if the existing one is not performing well. By making smaller changes backed by data, you reduce the risk of jeopardizing current conversion rates. 

A/B testing lets you focus your resources for maximum output with minor modifications. For example, you can just change the copy a little bit and see how people react to it. You would be surprised how even the smallest changes can positively impact the ROI.

You can also try it out before implementing a new feature. Before you show it to all users, A/B test it to understand how a portion of your audience reacts to it. Making changes on your website without testing may or may not pay off in the short and long run. But testing and then making changes can make the outcome a lot more predictable. 

Make data-driven decisions 

Since A/B testing is completely data-driven with no room for guesswork or gut feelings, you can quickly determine a “winner” and a “loser” based on your data. The metrics are for example time spent on the page, number of demo calls, click-through rate, and so on. 

By relying on statistical data, you reduce all risk factors connected to your subjective assessment. 

For this purpose, Optibase uses the Probability to Be Best (P2BB) measure. It’s a statistical measure used in A/B testing to evaluate the likelihood that a particular variant (A vs. B) is the most effective based on collected data. It’s calculated using Bayesian statistics, which consider the observed results and the uncertainty inherent in testing. 

How to read P2BB: 

  • Expressed as a percentage: P2BB is shown as a percentage. A higher percentage means a greater likelihood of that variant being the best performer in the test. 
  • Direct comparison: P2BB allows for a direct comparison between variants. For example, if Variant A has a P2BB of 70%, it suggests there’s a 70% chance that it’s more effective than other variants in the test. 
  • Informed decision making: P2BB helps you make decisions on which variant to implement. A variant with a substantially higher P2BB is usually the better option. 

When to determine a winner:

  • P2BB is dynamic: Keep in mind that P2BB values can change with ongoing data collection. Early in testing, the metric might be less stable and can become more reliable as more data is gathered.
  • Not absolute: P2BB is an indicator of likelihood, not a definitive measure of success. It should be interpreted within the context of the test and alongside other business metrics.
  • Use with other metrics: For a comprehensive evaluation, consider P2BB in conjunction with other metrics and overall business objectives.
  • Wait for 95% confidence: It is advisable to wait until a variant achieves a P2BB of at least 95% before declaring it as the winner. This high threshold ensures a greater level of confidence in the test results, reducing the likelihood of making a decision based on insufficient data or random fluctuations.

Here’s an example from an active A/B CTA test: 

By taking all that into account, you will be able to answer questions like this with confidence:

  • Which elements on your page drive conversions or impact user behavior? 
  • Which steps of your conversion funnel need to be improved?
  • Should you implement a new feature or not?
  • Will short or long forms perform better?
  • Which headline is the best? 

What to A/B test in Webflow?

Your website’s conversion rates usually determine the fate of your business or your product. So in order to maximize conversions, you need to optimize every aspect of your page for your target audience. 

By running A/B tests in Webflow, you can test practically anything on your website or customer journey.

Here are some of the most common elements to A/B test: 

1. Copy

Headlines and subheadlines

A headline is the first thing a visitor notices on your website. It can break or make your site. It’s what defines the first and last impression, playing an important role in whether or not they’ll go ahead and convert into paying customers. 

Headlines need to be short, straight to the point and catchy. Don’t overcomplicate and make them complex. They need to deliver the message in the first few seconds and tell the site visitor exactly what to expect. 

You can try A/B testing a few copies with different fonts and writing styles, then analyze which catches your visitors’ attention the most. 


The body of your website should clearly explain what the visitor should expect. It should also support the messaging in your page’s headline and subheadline. A well-written body can significantly increase the chances of turning your website into a conversion magnet. 

Here are some quick tips for drafting your website’s content:

  • Writing style: Use the tight tonality based on your target audience. Your copy should directly address the end-user and answer all of their questions. Don’t make it too general, but rather focus on a specific pain point that you’re solving. 
  • Formatting: Use relevant headlines and subheadlines, break the copy into small and easy paragraphs, and use bullet points or lists for better readability. Most of your site visitors will just skim the website, so keep that in mind when writing content.

2. Design and layout

Because every element on your website seems so crucial, businesses sometimes struggle with finding what to keep and what to get rid of. With A/B testing, this problem can be easily solved so you can improve conversions. 

For example, as a SAAS business, your landing page is the most important from a conversion perspective. Your potential customers want to get information about what you’re offering fast and then have an easy way of signing up if they’re interested. So for SAAS businesses, testing different design options and layouts makes the most sense. 

You could test your landing page with a short product demo and then without it. You can try how the CTA button works in the middle of your page, and then one version with a signup button in the top right corner only. You can also test if the version with two CTA buttons (one at the top and one at the bottom) works better than the version with just one main CTA button. The possibilities of improving your conversion rates are endless, and it’s very simple to do it in Webflow thanks to native integrations. 

3. Navigation

Another important element of your website that you can optimize is the navigation menu. It’s the most crucial element when we’re talking about user experience. Make sure you have a clear plan for your website’s structure and how different pages will be linked to each other - the flow has to be intuitive. 

Some common ideas how navigation usually works best:

  • Follow best practices: By placing your navigation bar in standard places like horizontal navigation on the top and vertical down the left, you will match the visitor expectations and make your website easier to navigate. 
  • Make navigation predictable: By keeping similarly themed or related content in the same bucket (for example “Services” or “Tools” you offer), you’ll be able to reduce your visitor’s cognitive load. Make sure they don’t have to spend a lot of time searching for stuff on your website, because that usually results in higher bounce rates. 

4. Forms 

Forms are how your potential customers get in touch with you. And they become even more important if they are a part of your purchase funnel. Just as no two websites are the same, no two forms addressing different audiences are the same. 

For some businesses, small forms might work the best, but long forms may do wonders for other businesses. You can figure out what works best for you easily by running A/B tests on different types of forms - short and long, mandatory information you collect, and so on. 

5. Call-to-action

The CTA is where all the action takes place - whether or not your visitors convert, if they fill out the signup form or not and other actions that have a direct impact on your conversion rate. A/B testing enables you to test different CTA copies, their placement, size and color, and so on. 

By experimenting with different positions and types of your CTA buttons and other elements, you will be able to understand which variation has the potential to get you the most conversions. 

6. Social proof 

Social proof may show in the form of recommendations and reviews from your customers or experts in the field, or as testimonials, awards, certificates, and so on. The mere presence of these proofs validates your claims on the website. 

With A/B testing, you can determine whether or not adding social proof is a good idea, or where it works the best - at the beginning of your customer journey or somewhere in between. It also tells you what kind of social proof will get you more conversions - whether that’s certifications or personal recommendations from other founders. 

7. Content depth 

Some website visitors will prefer reading long-form content that goes in-depth about what you do, while others will only skim the landing page and jump to conclusions. Those prefer short-form content that gets straight to the point. 

With A/B testing, you can determine which type of content your audience prefers. It can be done easily, by creating two pieces of the same content - but one should be significantly longer than the other, with more details. Analyze which compels your readers the most. 

Content depth also impacts SEO, so A/B testing is the perfect way to find the ideal balance between the two. 

How to start A/B testing?

A/B testing offers a very simple way of finding out what works and what doesn’t work in any given marketing campaign. As traffic acquisition becomes more difficult and expensive, it’s important that you offer the best possible experience to the visitors who come to your website. 

This will help them achieve their goals and allow them to convert in the most efficient way possible. A/B testing allows you to make the most out of your existing traffic and increase conversions. 

Step 1: Research

Before coming up with your A/B testing plan, you need to first research how your website is currently performing. If you’ve been using Google Analytics so far, then the job is already done. Just take a look at the data and determine which pages you’re going to be testing.

You should check how many users are coming to your pages, which pages drive the most traffic, the various conversion goals of different pages, and so on. 

You should prioritize pages that have the highest potential or the highest daily traffic, so you will be able to test more efficiently. 

Step 2: Create hypothesis

If you don’t clearly specify goals, you won’t know if your A/B tests are actually working towards achieving your business goals. The hypothesis can be more complex and longer, or a simple one like “Changing CTA button size will increase conversion rate by 2% on the landing page”. 

This is of course an optional step, but we strongly recommend that you follow it - especially if you plan on testing a lot more than just two different variations. It also helps in the future when you look back to check what was working better, and so on. 

Step 3: Connect your A/B testing tool 

Since you will be conducting A/B tests in Webflow, there are plenty of options available, but only one natively integrates with Webflow. This is why we recommend using Optibase.

Optibase is a Webflow app that offers a native way to set up A/B tests and split tests in the Webflow Designer within minutes without impacting your website loading performance. This app also lets you segment the audience based on their geolocation and screen size. 

There are two different ways to connect your A/B testing tool to Webflow.

Option 1: Install Optibase app for Webflow

  • Sign up to Optibase from the homepage. 
  • Open the Webflow Apps marketplace and find Optibase.
  • Click Install App to add it to Webflow. 
  • Launch the Optibase app. 
  • For a first time setup, you will need an API key. 
  • Navigate back to the Optibase web app. 
  • Open User → API Keys → Copy Secret API Key.
  • Paste it in the Webflow app and click Connect. 
  • Then paste the Optibase script into your Webflow site’s header. 
  • Publish the project. 
  • Click Done in the Webflow app. 

And that’s it, your Optibase app is set up in Webflow. You should be ready now to start A/B testing different elements on your page. 

Option 2: Use any other A/B testing tool

  • Sign up to any A/B testing tool. 
  • Copy and paste their script into Webflow. 
  • Follow their instructions in case you need to do anything else. 
  • Publish your project and you should be good to go. 

Now that your tool is connected to Webflow, you can start testing. But keep in mind that if you end up using any other 3rd-party solution, you will have to constantly navigate between Webflow and their tool, which could be a nuisance. 

Step 4: Add variations 

The next step after you successfully connect the A/B testing tool is to create a variation based on your hypothesis, and A/B test it against the existing version. 

With the Optibase app, you can test anything from specific page elements, to copy and design variations, to complete pages. Depending on how much traffic you’re getting or if you want to run more tests, you will be prompted to upgrade if you reach the limit. But to start, it’s completely free. 

For example, you can start light and compare two different headings, and connect conversions to the CTA button. It takes only a few clicks and you can start comparing. 

Depending on what you want to test, we offer extensive documentation for Optibase - both web app and the Webflow app. Click here to learn more about it. 

Step 5: Run your test

Once all variations are set up and you’re ready to finally start A/B testing your website, it’s time to run the test. 

Here you should consider a few factors for the test to be successful. 

Sample size

Sample size means the number of visitors, or the amount of traffic you need to accurately run a valid A/B test. When running your A/B test, it’s important to have a large enough sample size so you can achieve accurate results. 

If your sample size is too small, your test results will not be statistically valid or reliable at a high level of confidence. In other words, your tests might not be accurate because it’s impossible to tell how your entire audience actually behaves if only a few come to your site. 

It depends on the use case, but a general rule of thumb is that you need a minimum of 1.000 visitors and 100 conversions per variant for a highly reliable test. 

However, the more visitors you are able to test, the more accurate your results will be. 

Duration of the test

Another important factor to consider is the duration of your test. If you will be running your test for just a few days, you won’t be able to gather enough data to make accurate conclusions. 

So, when running A/B tests in Webflow, the average recommended testing time is 2 weeks, but you should always identify key factors relevant to your own conversion goals and determine the best length based on that - it could be even longer than 2 weeks, especially if you don’t have enough traffic yet. 

Step 6: Analyze results and make changes

This is the last step in your A/B testing campaign, so analyzing results is extremely important. A/B testing is designed for continuous data gathering and constant iterations to improve your conversion rates. 

Once your test concludes after a given time, analyze the test results by considering metrics like percentage increase, confidence level, direct and indirect impact on other metrics, P2BB measure, and so on. After you carefully analyze these numbers and compare them with your goals from before. 

If your test succeeded (it should be successful if you’ve followed the recommended guidelines), deploy the winning variation and see how your conversions increase. 

Also, keep in mind that A/B testing lets you systematically work through each part of your website to improve it, so make sure you implement it across your entire Webflow build. 

Tips to improve your A/B testing 

Here are some helpful tips to improve your A/B testing performance in Webflow:

1. Revisit previously concluded tests: 

Once you have tested each element or most elements on your website, revisit each successful as well as failed test. Analyze the results and determine whether there is enough data to justify running another version of the test. For example, you could have a lot more traffic after some time, or you completely changed your headline and it works better now - why not test a different CTA button again? 

2. Increase testing frequency:

You should always be cautious of testing too many elements together, but increasing your A/B testing frequency is essential in scaling your results. But make sure to plan the tests so no one affects others or general website performance. One solution to this is by running tests simultaneously on different web pages of your website or by testing elements on the same web page at different time periods. Having a dedicated testing calendar is useful here. 

3. Space out your tests: 

A general rule of thumb, not more than two tests should overlap each other. Do not ever compromise your website’s overall conversion rate because of increasing testing frequency. For example, if you have two or more critical elements to be tested on the same web page (for example, a product video and the main CTA button), space them out. Testing too many elements on the same page together makes it very difficult to determine which element impacted the success or failure of your test the most. 

4. Track multiple metrics:

You usually measure your A/B test’s performance based on a single conversion goal to help you find the winning variation. But sometimes, the winning variation can affect other website goals as well. For example, a video on the landing page can reduce bounce rate and increase time spent on site, but also contributes to increased signups. In that case, tracking multiple metrics would be recommended. 

5. Segment audience: 

One of the most effective ways to improve an existing experimentation is to design tests for specific audience segments. If you’re testing your entire audience, then you’re testing the average customer who doesn’t really exist. Obviously, testing each individual isn’t possible - but breaking them into segments is the next best thing. You can start by segmenting the audience based on their geolocation and screen size (desktop vs. mobile). Targeting them will reveal more meaningful insights into their behavior. 

Common mistakes to avoid in A/B testing

A/B testing is by far one of the easiest and most effective methods to increase your revenue and conversions. However, it demands planning, patience and precision. Making silly mistakes can cost your business time and money. 

To help you avoid making some of the most common mistakes related to A/B testing, here’s a list to remember: 

1. Invalid hypothesis 

Before you conduct your A/B test, you formulate a hypothesis. All the next steps depend on it. What should be changed, why it should be changed, what the expected outcome is, and so on. So if you start your experiment with the wrong hypothesis, the probability of your test being successful will decrease. 

2. Copying what others did

Yeah, someone else changed their signup flow and lifted conversions by 20%. But it’s their test result based on their traffic which is unique, their hypothesis and their business goals. Like mentioned previously, no two websites are the same - what worked for them might not work the same for you. So before you try and copy what worked for others, try to determine if it really makes sense for your case. 

3. Testing too many elements at once

Testing too many elements on a website together makes it very difficult if not impossible to pinpoint which element influenced the test’s success or failure the most. The more elements you test, the more traffic you need on that page to justify it. So you should always prioritize tests for successful A/B testing and incorporate them into your planning. 

4. Ignoring statistical importance

If you put your subjectivity or personal opinions into your hypothesis or into your A/B tests, they will most likely fail. No matter if the test succeeds or fails, you must let it run through its entire course (at least 2 weeks) so that it reaches its statistical significance. Every test will give you valuable insights and help you plan your next tests better. 

5. Not testing on enough traffic

Every A/B test should be done with the appropriate traffic to get accurate results. A general rule of thumb says that you need at least 1.000 site visitors and 100 conversions per variant, but the more traffic you have, the better test results will be. Using lower traffic than required for A/B testing increases the chances of your campaign failing or producing inconclusive results. 

7. Testing for wrong duration

Based on your website traffic and goals, you need to run A/B tests for a certain length of time to achieve statistical significance. The general rule of thumb is at least 2 weeks, but it can be longer depending on your goals. Running a test for too long or too short a period can result in the test failing or producing wrong results. For example, because one variant of your appears to be winning after the first few days, that does not mean that you should call it off before and declare a winner. 

8. Failing to adapt and make changes

A/B testing is an iterative process, with each test building upon the results of your previous tests. Businesses give up on A/B testing after their first test fails, but what you should really do instead is learn from previous tests and use these insights in the future. Do not stop testing after your first test, no matter the results. Test each element repetitively to find the most optimized version for your target audience. 

9. Not considering external factors

You should run all of your tests in comparable periods to get the most accurate results. For example, you can’t compare your highest website traffic with the days when you have the lowest website traffic (due to holidays, weekends, and so on), and draw conclusions from that alone. That’s why it’s also important to run your A/B tests for a longer period of time, to increase your chances for a successful test. 

10. Not using the right tools 

A/B testing is definitely gaining popularity, and that means multiple new tools on the market. Not all of these tools are equally good. Some tools will drastically slow down your site (especially if you have to install multiple scripts), some are not closely integrated with Webflow and can cause your website harm and data deterioration. A/B testing with faulty tools can risk your test’s success from the start, so make sure to use recommended and Webflow-approved apps. 

What are the impacts on SEO?

There won’t be any negative impacts on your Google rankings as long as you’re using tools that follow the recommended guidelines. Google explains in their article what you need to watch out for, and we’ll summarize the important parts here.

No cloaking

Cloaking is when you show one variant of content to humans, and a different variant to Googlebot. This is against the Webmaster Guidelines and you should not do it - you risk being removed from Google rankings. This would only happen if you play with the script yourself, not as part of a tool like Optibase, so if you run your tests normally then there’s nothing to worry about. 

Use 302 redirects

If you’re running an A/B test that redirects visitors from the original URL to a variation URL, use a 302 (temporary) redirect, not a 301 (permanent) redirect. This will tell the search engines that your redirect is temporary for the time being. JavaScript-based redirects are also approved by Google. 

Run tests for the proper duration

The time you will need to run your test varies depending on factors like your conversion rates, and how much traffic your website gets. A good A/B testing tool will tell you when you’ve gathered enough data to be able to draw accurate conclusions (in case of Optibase, this is measured as “95% Confidence”). Once your tests are concluded, you should update your site with the “winner variations” and remove all elements of the test as soon as possible. 


After going through this comprehensive guide on A/B testing in Webflow, you should now be fully ready to start planning your tests. Although this guide is specific to Webflow, the concepts and terms are general, so it can be used with other tools too. 

Follow each step carefully and make sure to keep in mind the recommendations and tips throughout this guide. A/B testing is invaluable when it comes to improving your website’s conversion rates, but you should avoid common mistakes that can impact its performance. 

If done with complete dedication and with the knowledge you have now after reading this guide, A/B testing can do wonders for your business. It will also help you improve your website’s pain points by eliminating all weak links and finding the most optimized version for your audience. 

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The ultimate A/B testing Webflow app
How to A/B test in Webflow - free guide  - Learn how to A/B test for optimal results through 9 chapters | Product Hunt