The Essentials of Hybrid Experimentation

By Paul Bernier

June 10, 2024


When running experimentation programs, most organizations start with client-side tests to experiment with the most common use cases, such as graphics, design scheme, and CTA copy and placement (as many as 85% of businesses prioritize CTA triggers for A/B testing). While client-side tools are well established and easier to use, they come with limitations, including lack of complexity, slower iterations, and flicker.

As a result, more organizations have begun to adopt server-side testing and feature flagging to expand into more complex use cases like search algorithms, checkout flow, pricing, inventory, shipping thresholds, and feature rollout. Unfortunately, this expansion is often held back by resource constraints and bottlenecks.

Wondering how you can keep the client-side benefits of quick iteration and shorter time to go live while opening up opportunities to tackle more complex experiments? The future of experimentation brings client-side and server-side testing together in what more and more organizations are calling “hybrid experimentation.”

Hybrid experimentation is more than just the addition of server-side capabilities to client-side; it’s the true combining of them under a single platform where multiple collaborating teams can use both to accommodate all experimentation use cases. By combining feature flags with client-side functionality, you can iterate on complex features at a much faster pace, extract more value from your experiments, and see higher conversion rates, all without increasing development costs or straining resources.

In this blog, we’ll dig deep to define hybrid experimentation, uncover its advantages, determine when you need it, and go over what to consider when implementing it.

What Is Hybrid Experimentation?

Hybrid experimentation takes your experimentation strategies and metrics from campaigns across A/B testing and feature flagging and brings them all into one unified platform. Traditionally, client-side, server-side, and feature flag capabilities have been kept separate. With hybrid experimentation, you no longer need to implement distinct experimentation solutions that require different skill sets to deploy. The lack of cohesion between standard testing solutions only strains your resources and delays optimization.

Unlike other testing methodologies, hybrid experimentation allows you to develop client-side variations and run them alongside a server-side test to see which combinations perform best:

In this example, the Image Grid is the server-side feature released once using a feature flag. In rounds 2 and 3, this winning feature is combined with client-side changes to create more unique versions. This iterative process is faster than separate tests because it involves a single release to isolate a critical piece of server-side functionality required for the experiments. Your team can then create variations on top of the feature flag using the client side instead of releasing new code for every iteration.

Merging client-side and server-side testing offers more than the sum of their parts. Hybrid experimentation streamlines resource use and accelerates testing. It also enables comprehensive testing of text, images, CTAs, layouts, algorithms, pricing models, checkout flows, and more across all devices and even within single-page applications (SPAs). This cohesive approach boosts efficiency and speeds up the optimization process without overburdening development teams.

Here are some of the ways hybrid experimentation can be useful for your organization:

  • Analytics: Measure hundreds of metrics in a unified measuring framework to track conversions and user engagement metrics across the same segmented audiences. You’ll also get direct access to performance and speed indicators.
  • Scope: A/B test any aspect of your site, app, or other digital platforms.
  • Resources: Reduce reliance on resource-intensive or overloaded development teams with cross-functional collaboration in one platform.
  • Velocity: Instead of waiting for lengthy code release cycles, you can introduce faster and more frequent iterations outside of the codebase.
  • Program Management: Prioritize, manage, and deconflict experiments in a single platform rather than across disparate environments.

SiteSpect is one of the only platforms that supports true hybrid experimentation by offering all client- and server-side functions in one interface, platform, and implementation. Hybrid experimentation with SiteSpect offers impactful benefits for organizations planning to refine their approach to experimentation. The Visual Editor gives marketers the power to modify, define, or redesign pages without developer assistance, while feature flagging and code editors provide plenty of power and flexibility for more technical users. This makes testing more accessible so other teams can optimize site elements, measure a wide range of metrics, and A/B test any aspect of the site to facilitate data-driven conversion rate optimization decisions.

Should Your Organization Use Hybrid Experimentation?

Wondering if hybrid experimentation aligns with your goals? It can be a game-changer for conversions, so here’s how to tell if it’s time to find a hybrid experimentation solution:

1. Faster Testing Velocity: Are your product managers looking for quicker testing turnaround and higher test volume? Hybrid experimentation can be ideal. The all-in-one approach can incorporate both client and server-side use cases without the slowdown often observed when organizations transition from client-side-only programs to server-side testing and feature flagging.

2. Limited Development Resources: Organizations with busy development teams benefit from hybrid experimentation as it reduces the burden on developers, who otherwise need to manage experiments, integrate third-party tools, and handle tech debt. This enables marketing and PM teams to run experiments more independently.

3. Infrequent Code Releases: Organizations with infrequent code releases are limited in how often they can push server-side changes and feature flag tests. Hybrid experimentation is particularly advantageous for this challenge. It allows those organizations to roll out changes to any site or app on any device completely independent of the code release cycle. SiteSpect’s proxy-based technology facilitates code changes without modifying the codebase and provides instant fixes and a kill switch just in case.

4. Immediate Results and Flexibility: Organizations aiming for faster results will find hybrid experimentation can get the job done. By allowing you to build out several client-side variations on the same server-side test within the SiteSpect UI, you can dive deeper with more specific, varied, and complex changes even in a single round of testing.

Hybrid experimentation is perfect for organizations needing faster testing iterations, reduced developer involvement, and more frequent and flexible experimentation capabilities.

Implementing Hybrid Experimentation: Consider This

It might sound difficult to combine all of your tests and metrics into one platform, but it actually makes running your tests a lot easier—and it doesn’t have to be a challenge to set up. With a hybrid experimentation-enabled solution like SiteSpect, managing hybrid tests is straightforward and efficient.

  1. The first step is to identify an experimentation platform with combined client-side and server-side testing capabilities. SiteSpect is uniquely positioned to offer full-spectrum experimentation with a single seamless integration that covers all testing functionality in one place.
  1. Next, ensure that your tool can run a high volume of tests simultaneously. SiteSpect’s platform enables teams to run dozens of tests at once, whether on the client side or server side. This is a good time to make sure your chosen platform can develop tests and features outside of your codebase. This capability is crucial for maintaining high testing velocity and reducing the burden on development resources.
  1. Finally, begin isolating key server-side functionalities for your baseline tests. To do this, review your testing roadmap to identify relevant server-side opportunities to revisit. Once you’ve landed on critical functionality, your team can use hybrid experimentation to release new server-side changes and continue iterating by building client-side tests on top.

This holistic approach makes SiteSpect an ideal solution for organizations seeking to maximize their experimentation capabilities and drive continuous improvement.

Final Thoughts

When it comes to delivering business value with reduced strain on development resources and greater optimization potential, the transformative power of hybrid experimentation is clear.

SiteSpect’s testing platform integrates flicker-free client-side and server-side testing frameworks with the ability to add feature flags in one place, boosting testing velocity and streamlining resource utilization. Ultimately, hybrid experimentation offers a comprehensive solution for organizations seeking to refine their testing strategies and drive continuous improvement.

Ready to find out more about how you can apply hybrid experimentation at your organization? Request your personalized demo to see it in action.


Paul Bernier

Paul Bernier

Paul Bernier is Vice President of Product Management at SiteSpect. He has a background in website optimization, recommendations, and development, as well as web analytics. He is based in Boston.

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