All You Need To Know About Server-side A/B Testing
What would customers prefer, a product layout with or without a model?
Do customers engage more if we lay out the bestsellers by price?
What if it’s the best selling item over just the past 5 days? 10 days?
Here’s a simple answer — run experiments and let’s find out. Welcome to the world of A/B testing.
In today's competitive digital landscape, businesses need to continually innovate and optimize their products and services to stay ahead of the curve.
To achieve this, data-driven decision-making is becoming increasingly important, and A/B testing is one of the most effective tools for this.
Traditionally, A/B testing has been performed on the client-side, where variations of a website or app are shown to users and their behavior is tracked. This is a common strategy by marketing teams when optimizing the front-end features of a website.
However, client-side testing has its limitations, such as the potential for inaccuracies due to browser inconsistencies, ad-blockers, and significant performance penalties.
As a result, server-side or edge side A/B testing is emerging as an attractive alternative for businesses that are serious about optimizing their products and services.
In this post, we will delve into the world of server-side A/B testing, what it is, how it differs from client-side testing. We'll also explore some best practices for implementing server-side A/B testing to help you make the most out of this powerful optimization tool.
Finally, we’ll discuss why it might be a better option for your business.
What is server-side A/B testing?
Server-side A/B testing is any type of testing that occurs (or is being carried out) on the web server and then sent to the user’s browser. Its implementation on the server lets you run a series of advanced experimentations on extensive parts of your application or feature before final deployment.
The premise of A/B testing on the server-side is simply to use data analytics to evaluate the preferred variation of a page or design by the end users. This allows you to accurately track their responses to different experiences, and then compare the data to identify the one with the most promising results.
Related → Real User Monitoring vs Synthetic User Monitoring
Here’s how it works.
For example, imagine testing two variations of a landing page for your ecommerce website to see which one drives more conversions.
- Landing page A has a minimalist design with a simple layout, and two CTAs.
- Landing page B has multiple images displaying the product, cluttered designs, and six CTAs.
In the server-side A/B test, the algorithm splits the website traffic. Therefore, 50% of users will interact with landing page A, while the other 50% interact with landing page B.
Based on the results of the test, make a decision about which landing page to use on your website or application going forward. Implement the winning variation for the end user and continue to monitor its performance to ensure that it continues to deliver positive results.
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Related → Server-side caching vs Client-side caching [And which is good for your website]
What are the differences between server-side A/B testing and client-side A/B testing?
The key highlighting factor differentiating server-side from client-side relates directly to the mode each experimentation was carried out.
Based on this mode of implementation, certain tests and modifications cannot be done on the client-side as it’ll hinder user experience.
At the same time, if you switch to synchronous loading for testing, it’ll affect the page load time causing the user to stare at a blank screen until the page is fully loaded.
For a broader breakdown on the differences between these two test, check the table below:
In conclusion, the choice between client-side and server-side A/B testing will depend on the specific needs and requirements of the website or application being tested. For the most part, the best choice for testing will depend on factors such as goals of the test, the resources available, and the desired level of accuracy.
💡 [Case study] → Read how Bokksu decreased page speed score by 86 points.
Related → What is First Input Delay (FID) [+ How to Improve it]
What are the applications of server-side A/B testing?
1. Testing optimization capabilities of E-commerce websites
E-commerce websites are often complex integrations of front and back-end systems that aids the entire shopping experience be seamless for users. This also means it requires testing a variety of elements in order to achieve the best possible results.
Therefore, using server-side A/B testing is the best possible solution to test different variations of the ecommerce website under a controlled environment without impacting the user’s shopping experience.
For example, you could use server-side A/B testing to compare different product page layouts, checkout processes, and pricing strategies. The results of these tests can be analyzed to determine which variations perform best and lead to increased conversion rates and revenue.
💡 [Case study] → Read how MyKitsch cut load times to <1 second and hit record sales
Related → What is headless ecommerce? [+Benefits]
2. Executing Google Tag Managers (GTM) on the server-side
The implementation of server-side tagging with GTMs is simply the process of sending data from the server-side (backend) to the GTM. This is because, with server-side tracking, it’s easier to track interactions on backend management systems that would normally be difficult to track via the client-side (web page).
💡Side note → The backend management system is responsible for tasks such as storing and retrieving data, processing requests, and handling user authentication and authorization.
Once data is sent directly to the server from the GTM, you can easily track server-side events and actions such as logins, form submissions, and transaction completions.
To implement server-side tagging with GTM, you will need to set up a server-side container in GTM and configure it to receive data from your server. This can be done by using a server-side library or API provided by GTM.
💡Note → The process below is provided by Google on server-side experiments. For advanced explanation, read Google’s guide on implementing server-side tagging with GTM here.
- Open your optimize account.
- Select a container.
- Enter your experiment name
- The URL field is ignored here. Enter a placeholder URL that doesn’t exist on your website.
- Select A/B test
- Click create.
- Set experiment objectives
Use objectives to measure the results of your experiment.
- In your experiment page, click Add experiment objective under Measurement and objectives.
- Select a primary objective from the dropdown list.
- Set experiment targeting
Your server-side code handles experiment targeting, so Optimize doesn't use the information you enter here. However, Optimize requires you to set a URL rule.
To set experiment targeting:
- In your experiment page, click Add variant under Targeting and variants.
- Enter a variant name (e.g. Variant 1) and click Done.
- Click + Add URL rule under Page targeting.
- Select the equals match type and enter SERVER_SIDE for the value. Do not use a URL or string that begins with "http" or "https" because if your site is tagged with Optimize, this server-side experiment will never be triggered for your site.
- Click Add.
To create variants:
- In your experiment page, click + Add variant under Variants.
- Enter a variant name (e.g. Variant 1) and click Done.
- Click Add.
Start the experiment
In your experiment page, click Start.
Get the experiment ID
The experiment ID is available under Google Analytics in the Measurement and objectives section.
Once the server-side container is set up, you will need to send data from your server to GTM using a tag and triggering mechanism. This typically involves sending an HTTP request from your server to GTM, which contains the data you want to track.
3. Enhancing personalization for omnichannel and cross-channel businesses
The complexity of implementing server-side A/B testing proves to be one of its strongest points — especially when it comes to personalization. Its controlled environment provides the opportunity to tailor online experiences to users based on their preferences and behavior.
Like in this example below, there are two variations that align with the experience of the shoppers — all of which are served from the server-side.
Let’s say you run an ecommerce store with a BOPIS (buy-online-pick-up-in-store) option. With server-side A/B testing, you can segment your users and tailor their experiences based on repeat visitors, walk-ins, new shoppers, and shoppers with abandoned carts. The results you get for this test can help you determine the most effective way to increase your engagements and conversions.
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4. Implementing feature flags during development lifecycle
Feature flags (also known as, feature toggles, or feature switches) are software development concepts or approaches that enable you to turn features ON/OFF during their run time without deploying new or additional code. This allows you to control your features and also segment its usage for users depending on their development stage.
Your development team can segment users into two categories and create a controlled environment using server-side A/B testing. Then, deploy the feature flag to toggle ON the feature for half the users, and OFF for the remaining half. With this, you can evaluate user reactions to these changes by using metrics such as app usage, and conversion rate.
Some other common use cases of feature flags include:
- Canary releases
- Gradual rollouts
- Dark launching
- Toggling functionality
- Kill switch or rollback
Overall, the concept behind the feature flag is to use server-side A/B testing to test features in a controlled environment.
💡 Pro Tip → You can run a faster WordPress website by simply using the Edgemesh plugin. Plus, it’s a one-click integration that requires no changes to your existing code.
What are the benefits of server-side A/B testing?
1. Increased accuracy on test results
Tests performed on the server are more accurate and reliable as they’re independent on the client’s device. This is contrary to the client-side A/B tests as it’s susceptible to browser and device compatibility issues, frequent down times, high latency, and poor load time.
A common scenario in a client-side A/B tests is the inconsistent user experiences due to the dependence of client-side A/B testing on user device, browser, geolocation, and internet connection.
However, running this same test on the server-side means the information is stored and processed entirely on the server. This way, all users receive the same experience across all platforms leading to consistent test information irrespective of the technology used.
Related → What is time to interactive (TTI) [+ How to improve]
2. Improved performance
One of the major downsides to client-side A/B testing was its poor performance — especially the slow loading time and flickering effect.
Meanwhile, with server-side A/B testing, there’s less latency, and faster page load time due to the reduced amount of data that needs to be transmitted between the server and the client.
Additionally, the performance capabilities of server-side A/B testing spreads further in aiding the scalability of websites. This means it’s better suited for handling high traffic, and processing large volumes of user requests.
With this, organizations can ensure that their testing process does not become a bottleneck for their website or application, even as it grows and becomes more popular over time.
👀 Quick Tip → Use Edgemesh Edge solution to speed up your website in a matter of minutes— all with a few lines of code.
💡 [Case study] → Read how Gorjana page load time dropped by 50%
3. Better data security and privacy protection
Majority of your user’s data is vulnerable when left exposed, stored, and processed on the client-side. In some cases, if the user’s device has been exposed to a phishing or malware attack of some sort, it can find its way to your data and potentially corrupt your database.
In contrast, server-side A/B testing keeps all tests and data on the server — hence reducing the risk of unauthorized access to user information. Also, the testing environment created on the server is highly secure during and after the development cycle — even down to the final deployment.
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4. Greater control on testing process and environment
Server-side A/B testing allows you to set the test environment and parameters for each of your test variations. This means, for each test, you can customize the entire user experience including the type of users, device, operating system, and geolocation without relying on the client-side.
For example, say you’re trying to segment paid users and those on waitlist for a product release. You can use the server-side A/B testing to control:
- Size of the test group (x number of paid users)
- Duration of the test (use the product for the next 30 days until trial expires)
- Conditions under which the test is triggered (if X user is paid (+), then they can access the product. If X user is on the waitlist (-), then can’t access the product.
This process helps you design and run tests that align with your goals and objectives. With this, you can make more informed decisions based on real user data.
5. Faster and continuous delivery of seamless omnichannel integration
Creating an interconnected ecosystem for your business is one of the best use cases of server-side A/B testing. This involves deploying the same variation of landing pages, features, mobile apps, email campaigns to users irrespective of what channel or device they’re using.
This is also useful for geo-based websites to tailor the experiences of users across different locations and channels.
For example, a travel research platform like TripAdvisor uses server-side A/B testing to deploy different variations of their website based on the user’s location.
The baseline here is simply to ensure that users' experience remains the same on whatever platform they choose to continue their journey.
💡 Case study → Read how Easy Standard saw a 5x faster server response time.
What are the challenges of server-side A/B testing?
There are only two major challenges facing server-side A/B testing:
1. Technical complexity
To successfully conduct server-side A/B testing, you need to have the necessary technical infrastructure and resources in place. This includes, a high-end server to host the test, and specialized tools, and software to help collect and analyze the test data.
In addition, to consistently run server-side A/B tests, you’ll require backend developers experienced in implementing complex systems and processes. This can be a deal breaker for you if you have a limited budget to invest in hiring good talents and also infrastructure.
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2. Slow implementation time and testing speed
The complex operations involved in running server-side A/B tests take a toll on its execution time since the test information is sent from the client to the server. This process is slower when compared to client-side A/B tests that are almost instant to implement and also faster to execute.
Another downside to server-side A/B tests is the speed of the server used to host the testing environment. If the server has poor network condition and performance issues, this will impact the speed of the test — and also the accuracy of its results.
Overall, the benefits of server-side A/B testing, such as improved security and greater control, can make it the better and highly recommended option.
💡 [Case Study] → Read how Cariuma saw a 74% decrease in server response time.
How do you choose a server-side A/B testing solution?
Simple — evaluate its core factors to see if it’s the right fit for your business.
Well, here’s the thing, there are several server-side A/B testing solutions flooding the market— hence finding the perfect solution almost doesn’t exist if you know what to look out for.
To make this easier, we’ve compiled five important factors to consider before choosing a server-side A/B testing solution.
1. Evaluate the cost structure
All server-side A/B testing solutions offer different kinds of pricing models. Some are subscription based, while others are customized depending on your requirements. Some of which include the number of tests you want to run, the size of your audience, and the complexity of your testing requirements.
It’s important to review the cost structure of each solution and compare it with your available budget. Also take into account the benefit of each feature to see if it aligns with your goals and objectives.
2. Assess the integration with your technology stack
System compatibility with your technology stack is highly imperative to the success of any test you’ll run on the server. This is because it helps ensure a seamless and efficient testing process when integrating an A/B testing solution with your website, mobile app, or marketing software.
Another important part to check out is the solution’s API and its integration capability with other technologies in your stack. This way, you’ll minimize issues of redundant, duplicate or siloed data that can ruin your test results.
💡 Pro Tip → Edgemesh is designed to integrate with leading ecommerce platforms such as Shopify, Magento, and BigCommerce.
3. Review the usability
Most server-side A/B tests solutions aren’t built for “ordinary use” — hence, making it hard for non-tech individuals to use or run.
However, when evaluating potential solutions, it’s highly recommended to choose one that makes it easier to design, run, and analyze tests without extensive technical knowledge. This way, you can minimize the time and effort required to get started — and instead, focus on improving your website or application.
4. Analyze the scalability options available
Oftentimes, when you plan to switch to a server-side A/B testing solution, you might have limited idea on scope of the entire project. For instance, you might be making the switch just to run simple marketing campaign tests on five channels. But you later discover that the more tests you run, the better results you’re getting, and at that point, you’ll like to expand into more channels.
However, if the solution you're using doesn't support such, you might be forced to forgo your entire data and test results for a better option. Ideally, you should be looking for a solution that can help you handle occurrences such as increase in traffic, functionality, test size, and channel size as your business grows.
5. Ensure there’s a 24/7 support team
It’s important to use a solution that offers a 24/7 support team that can help you quickly resolve any issues or challenges that may arise during testing. Also, they can assist in areas such as troubleshooting systems, account management, training employees, and even providing educational materials for an easier learning curve.
With a strong support team, you can easily find ways to optimize your tests and also have the expert guidance to quickly resolve issues or challenges when using the solution.
Thinking of making the switch to server-side A/B testing?
Yes — you should. It’s a non-debatable option.
By now you should have weighed your options and evaluated which is a better investment for your business. While client-side A/B testing would likely solve all your immediate issues at a relatively low-cost, the downsides can also affect your bottom line.
On the other hand, with a server-side A/B testing solution you’re rest assured of the accuracy and reliability of the test results.
This further translates into advantages such as:
- Easy deployment and execution of test programs
- Improved algorithmic efficiency for website or app modification
- Better testing capability across your tech stack — and many more.
But what better way to handle server-side A/B testing than with Edgemesh?
Use Edgemesh, the #1 server-side testing solution for your business.
With Edgemesh, you can quickly and easily test different versions of your website to determine which one performs better, all without any changes to your website's code or frontend. This technology also offers a range of benefits to companies of all sizes, including:
- Improved website performance: With Edgemesh, your website can be optimized without adding any additional client-side code or impacting your website's performance. This means faster page load times, better user experience, and higher conversion rates.
- Reduced development time: Edgemesh's server-side testing eliminates the time spent making changes to your website's code or deploying new versions. With this, you can focus on your core development work and let Edgemesh handle the testing and optimization.
- Increased revenue: Edgemesh also helps you quickly identify the best-performing version of your website, leading to higher conversion rates and increased revenue for your business.
- Improved user engagement: By testing different variations of your website, you can learn what resonates with your audience and make changes that keep them engaged and coming back for more.
- Customizable experiments: Edgemesh can help you set up customized experiments to test different variations of your website This includes changes to layout, content, and messaging. Hence, making it easier to tailor your testing to your specific business needs.
Overall, Edgemesh's server-side A/B testing solution is an essential tool for any company looking to optimize their website and increase conversions.
So why wait? Sign up for Edgemesh today and start testing!