The most effective websites adapt to customer demand and fluctuating trends. This means that during design and launch, web developers and designers need to research which elements work and which don’t. Testing these designs is an important part of this process — and that’s where A/B testing comes in.

What’s A/B testing?

A/B testing is a controlled experiment that shows users a slight change between designs and tracks data to identify which version performs better.

It compares the real on-page performance of one version (design A) against that of another (design B). Version A is usually the existing design, or control, while version B tests a new element.

This testing works by randomly redirecting a proportion of the site’s users to either design A or design B. It monitors website performance and compares how the two sets of users interact with each version. With this information, you can make website improvements you know users will respond to.

A/B tests can consider anything from the tiniest changes in user interface (UI) elements, like the color of a call to action (CTA) button, to the most comprehensive, like testing two completely different landing pages or checkout sequences.

Why use A/B testing tools?

A/B testing tools help you:

• Track data and continuously improve the website. A/B testing tools measure changes in key performance metrics over time, meaning you can continually find areas to tweak and improve a site’s design.

• Protect your SEO work. You might want to make changes to a webpage already ranking in search results but don’t want to risk losing your search ranking for the existing page or being flagged by an algorithm for providing duplicate information. Luckily, A/B testing tools use 302 redirects and canonical tags to tell Google the content exists elsewhere and that this duplication is only temporary.

• Increase conversion rates. A/B test metrics show you how effectively your sales funnel moves customers through the site. You can identify the least effective points and experiment with improvements.

• Lower your bounce rates. Bounce rates track how often people visit your website but leave before viewing a second page. The results of most A/B tests show you how long customers stay on each version of the site, allowing you to identify and remove any features leading to higher bounce rates.

Types of A/B testing

Standard A/B tests compare differences in one variable, or web element. Web designers usually set out to perform a test to answer a question about which version performs best: Should the CTA button be blue or green? Should the title of this email campaign be long or short? Does reducing the number of steps in the checkout process decrease shopping cart abandonment? Comparing the data between both versions, like whether more people clicked on the blue or green CTA, shows which design site visitors prefer.

Designers can also use standard A/B testing tools for landing pages to compare an entirely new version of a website with the current one.

A/B/n tests examine more than two versions of an element at once. It might take the same CTA button and test how it performs in blue, green, pink, and purple to determine which is best. A/B/n tests are useful if there’s enough site visitor traffic to yield robust data for multiple options.

Multipage tests evaluate user flow between a site’s entire sequence of pages. You can use multipage tests to determine whether using a different style of copy (for example, more or less formal language, fear-focused or confidence-building tone) or design (for example, layout or color scheme) influences users’ progression through the site.

Multivariate testing evaluates multiple changes in several elements to determine which combination performs best. It might change the color, shape, and placement of a CTA to compare how it performs to the existing one or test different combinations of those changes. Multivariate testing can be more efficient than standard A/B testing because it collects more information at once about user preference, like whether a red rectangle or a green circle performs best as a CTA — but, like A/B/n tests, reliable data only comes from a larger number of visitors.

8 A/B testing tools for different needs and budgets

Which online tools are the most useful for A/B testing depends on your needs, both for outcomes and budget. And if you’re working with clients, they might prefer a tool that’s cost-effective or offers straightforward presentations of data instead of complicated reports.

No matter which tool you select, make sure that it provides accurate data, reports on all metrics of interest, and integrates seamlessly into the website.

In most cases, you don’t have to spend anything at all, thanks to high-quality free A/B testing tools. We’ve put together a list of eight useful tools, split between what’s best for individuals and small businesses and for large businesses.

The best A/B testing tools for individuals and small businesses

1. Google Analytics 4

Google Analytics is the dominant performance monitoring site — over 37 million live websites use this tool. Google is moving A/B testing to Google Analytics 4 (GA4), which will replace the popular Google Optimize, due to be phased out in September 2023.

Price: Free 

Advantages:

• Integrates with a vast number of apps and software platforms, including Webflow 
• Intuitive UI
• Relatively small time investment to learn the basics (Google’s suggested time for the introductory course is 4–6 hours)
• Part of a complete analytics package that integrates with other Google services, such as Google Ad Manager and Google Merchant Center

Disadvantages:

• Users can create a maximum of 25 user properties, limiting the possibilities for audience segmentation
• Privacy concerns regarding user data

2. VWO

Rather than offering a comprehensive website optimization service, VWO focuses solely on A/B testing. VWO can run multivariate experiments or multiple experiments simultaneously and uses a multi-arm bandit algorithm to direct more users to the most effective version. It also includes heatmaps and video recordings of user behavior to better understand the user journey.

Price: Free starter pack for up to 50,000 visitors per month. Advanced plan costs vary on a need-to-need basis.

Advantages:

• Includes both a visual editor that can be used without coding experience and a code editor for developers
• Offers audience segmentation
• Uses probability-based UI to prevent you from jumping to conclusions too early
• Includes qualitative elements such as replays and pop-up surveys
• Has low impact on site and app loading speed
• Protects user privacy

Disadvantages:

• Doesn’t have flexible contracts (there may be high fees for exiting early) 
• Might have slow customer support
• Reports of some suddenly losing data and features

3. HubSpot A/B testing kit

HubSpot is a customer relationship management (CRM) platform organized into “hubs” for website building, blogging, and marketing. Its free testing kit includes information on A/B testing, a spreadsheet-based template to track the results of A/B tests, and a simple statistical significance calculator.

Price: Free basic testing kit, professional ($800 per month, plus a $3,000 onboarding fee) and enterprise ($3,600 per month, plus a $6,000 onboarding fee) plans

Advantages:

• Simple starter kit for people or businesses who are doing A/B testing for the first time
• Free academy providing a range of courses and certifications in marketing and sales

Disadvantages:

• Limited features in the free version
• Paid version likely beyond the reach of individuals and many small businesses

4. Crazy Egg

Crazy Egg is a compromise between basic, free tools and more comprehensive and complex ones. A 30-day free trial lets you experiment with the tools to explore whether they work for you before committing to a paid plan.

Price: From $24 per month with a 30-day free trial

Advantages:

• Provides more advanced features (heatmaps, recordings, surveys, and traffic analysis) at a reasonable price
• Few steps to implement
• Reliable tracking

Disadvantages:

• Reports of session recordings being unreliable
• May be too minimal for advanced users

5. Apptimize

Apptimize is a mobile-first platform that focuses on how to increase user engagement — and therefore revenue — in native mobile apps. Apptimize tracks the effects of changes across multiple channels (such as mobile apps, mobile sites, in store, and call centers).

Price: Comes in both free and paid versions with a 30-day free trial

Advantages: 

• Allows you to run a wide range of experiments of differing complexity
• Intuitive WYSIWYG editor
• Highly efficient A/B testing
• Can provide a personalized user experience by tracking the behavior of individual users across multiple channels
• Links A/B test results and revenue

Disadvantages:

• Less intuitive interface
• Users report a steep learning curve when starting out with this product

The best A/B testing tools for enterprises

6. AB Tasty

Brands such as L'Oréal, Panasonic, and Clarins use AB Tasty, which means it can handle the high traffic of a large business. The tool’s primary focus is optimizing the user experience.

Price: Custom pricing (contact AB Tasty for a custom quote)

Advantages:

• Responsive and proactive support team (including regularly scheduled catch-ups with customer success agents)
• Widgets feature 
• Intuitive interface
• Implementation is only a few steps
• Includes heatmaps and session recordings
• New features rolled out frequently

Disadvantages:

• May adversely impact user experience due to slower loading speeds
• Visual editor can be complicated to manage and may require a developer

7. Convertize

Convertize specializes in using insights from psychology and neuromarketing to understand and improve the customer journey. Its smart persuasion approach is built on behavioral economics and research on attention, association patterns, and memory. Monthly coaching is available following a site audit ($4,800+) and an optimization plan ($12,300+) — an expensive but potentially worthwhile investment.

Price: A/B testing is provided as part of the ongoing coaching program ($7,200+ per month)

Advantages:

• Drag-and-drop editor 
• Projects delivered in English, French, Dutch, German, or Italian
• Integration of insights from neuromarketing

Disadvantages:

• High price point

• Some customers have complained that customer service became patchy after Glassbox acquired the testing platform in 2021

8. Adobe Target

Adobe Target integrates with the broader Adobe Analytics platform and allows A/B, multivariate, and multi-armed bandit testing. Adobe Target offers advanced personalization and audience segmentation features, allowing for closely targeted campaigns.

Price: Variable (must request a consultation)

Advantages:

• Focus on personalization and targeting specific audience segments
• Comprehensive tracking and optimization of the user experience
• Appropriate for B2B marketing
• AI-based recommendation and personalization features

Disadvantages:

• High price point
• No reporting dashboard
• Requires considerable effort and support to learn
• Doesn’t integrate well with non-Adobe tools
• Some reports of slow load times and flicker

Use A/B testing tools to take design a step further

A/B testing allows you to take a scientific approach to virtually any aspect of web design and marketing, including color palettes, contact pages, and even email marketing campaigns. The design possibilities are endless — it’s time to start testing. Check out Webflow’s visual website builder to explore the possibilities and design your next website.