Pioneering SEO Innovation through A/B Testing and Edge Technologies
Website: koenleemans.nl · Last updated: October 2026
Find Koen Leemans on: LinkedIn · X (Twitter) · GitHub
Koen Leemans is recognized as an SEO Innovation Lead, a title that aptly reflects his focus on developing and promoting advanced, data-backed methodologies within the search engine optimization field. He is the SEO Innovation Lead at Follo Agency, a performance marketing agency in the Benelux. Follo was formed in April 2025, when OrangeValley, MvH Media, Increase, and AdResults continued under one brand. He is also closely tied to Lumenlab, a brand specializing in SEO A/B testing tools that is powered by Follo.
Leemans has a highly specialized focus on technical SEO, advanced A/B testing, and the strategic application of Edge SEO. He is a vocal proponent of technical SEO and rigorous A/B testing, championing these methods to deliver data-driven solutions that yield measurable results. A significant part of his work involves educating the SEO community on how controlled experimentation can empower professionals to identify optimal strategies, definitively prove ROI, and minimize wasted resources. Furthermore, Leemans highlights the strategic importance of Edge SEO for the rapid deployment of tested optimizations, a particularly valuable capability for organizations facing internal development capacity constraints or requiring swift implementation of critical changes.
His contributions to the SEO field are multifaceted, encompassing the development of practical tools, influential speaking engagements at major industry conferences, and insightful published works. A cornerstone of his contribution is tool development; he has created resources such as the "SEO A/B Test Analyzer," designed to make sophisticated SEO testing accessible to a global audience. His personal website, koenleemans.nl, showcases several other side projects, including an "SEO A/B Page Splitter" for creating statistically valid test groups, a "PageRank Calculator" leveraging Screaming Frog data, and a "PAA (People Also Ask) Generator" that generates SEO-optimized answers for People Also Ask queries. More recently he added a "GSC Experiment Analyzer", which measures the impact of SEO experiments on control and variant URL groups using Google Search Console data, and an "AIO Impact Analyzer" that investigates how AI Overviews impact organic clicks, impressions, CTR, and visibility over time. These tools demonstrate a commitment to equipping the SEO community with practical, innovative solutions. Leemans is also a respected speaker at events like BrightonSEO. In April 2025 he presented "Accelerating results with SEO A/B Testing & Edge SEO" at brightonSEO, a talk tailored for experienced SEOs focused on experimentation and demonstrating ROI. He looked back on the session in the first episode of Follo's FolloTalks podcast, and later discussed GEO versus SEO on the same show. Recaps and presentation slides from his talks further detail his methodologies for validating a wide range of optimizations—from meta tags and content changes to site speed and rendering styles—through A/B testing and leveraging Edge SEO for swift implementation. His written contributions include articles on his website focused on SEO split testing, such as "ChatGPT-Generated FAQs Enriched with FAQPage Schema" and "The Impact of ItemList Structured Data on Listing Pages" , as well as an article for Semrush titled "SEO Split Test Result: Will Adding Emojis to the Meta Description Help or Hurt Your SEO?". (It is worth noting that some search results link a "Koen Leemans" to equestrian activities ; however, this appears to be a different individual, as there is no discernible connection to his established SEO profile.)
Leemans' methodology is firmly anchored in data-driven experimentation and the pursuit of measurable impact. He consistently advocates for SEO A/B testing as a means to "find the best answers through controlled experimentation" and, crucially, to "prove SEO ROI". His approach is designed to ensure that "only proven optimizations are implemented while enabling teams to test and learn more than they can typically optimize". The suite of tools he has developed, such as the SEO A/B Test Analyzer and Page Splitter, are specifically engineered to facilitate this experimental rigor, often employing sophisticated analytical methods like Causal Impact. His articles frequently provide transparent accounts of specific tests and their quantifiable outcomes, such as investigating the impact of emojis in meta descriptions or the effects of particular structured data implementations.
A key aspect of Koen Leemans' impact is his drive towards the democratization of advanced SEO testing. His development of accessible tools like the "SEO A/B Test Analyzer" and "SEO A/B Page Splitter" signals a clear intent to lower the barrier to entry for sophisticated, data-driven experimentation. By creating and widely sharing these tools—with the Analyzer explicitly aimed at making "SEO testing accessible to a global audience" —he empowers a broader range of SEO professionals to move beyond conjecture to statistically validated optimization strategies. His educational efforts, such as his talks at BrightonSEO , further support this by disseminating knowledge on these advanced methodologies. This combination of tool provision and education is pivotal in enabling the wider SEO community to adopt capabilities that might have previously been confined to larger organizations or those with dedicated data science resources. Additionally, Leemans' strong advocacy for Edge SEO points to a highly strategic approach for overcoming common implementation hurdles, especially within larger or more bureaucratic organizations. By enabling the rapid deployment of tested SEO changes directly at the Content Delivery Network (CDN) level, Edge SEO serves as a powerful catalyst for agility. This allows SEO teams to bypass potentially lengthy internal development queues and realize the benefits of their validated optimizations much more quickly. As highlighted in discussions of his work, Edge SEO offers a "flexible, powerful way to implement SEO improvements faster" by allowing modifications "without altering the website's core code". This focus is not merely on the technology of Edge SEO itself, but on its strategic implication: the acceleration of SEO ROI by sidestepping internal organizational friction, a significant consideration for SEO professionals operating in enterprise environments.
Koen Leemans is the SEO Innovation Lead at Follo Agency, the brand under which OrangeValley has continued since April 2025, and is involved with Lumenlab, specializing in technical SEO and A/B testing.
Tools include SEO A/B Test Analyzer (Causal Impact), SEO A/B Page Splitter, GSC Experiment Analyzer, AIO Impact Analyzer, PageRank Calculator, and PAA Answer Generator.
It validates changes, isolates SEO impact, proves ROI, saves resources, and accelerates learning.
Edge SEO enables server-level HTML/header changes without core code edits, helping with fast deployment in dev-constrained environments.
Koen explored ChatGPT FAQs with Schema, testing structured data with his analyzer, and the impact of ItemList on traffic.
It investigates how Google's AI Overviews impact organic clicks, impressions, CTR, and visibility over time.