A/B testing in the UK: market share ranking

Experiments and feature flags.

#	Technology	United Kingdom	Global	Netherlands	Italy	Spain	Japan	Latin America
1	VWO	1.5%	1.6%	2.2%	0.3%	1%	0.4%	0.9%
2	Convert	0.8%	0.3%	1.4%	0.2%	0.2%	<0.1%	0.2%
3	AB Tasty	0.6%	0.3%	0.2%	0.3%	0.5%	0.1%	0.1%
4	Optimizely	0.5%	0.6%	0.3%	0.2%	0.4%	0.1%	<0.1%
5	Google Optimize (retired)	0.3%	0.3%	0.4%	0.2%	0.4%	0.4%	0.3%
6	Kameleoon	0.1%	0.3%	0.3%	0.2%	0.2%	<0.1%	<0.1%
7	Adobe Target	<0.1%	0.3%	<0.1%	0.1%	0.1%	<0.1%	<0.1%
8	GrowthBook	<0.1%	<0.1%	<0.1%	<0.1%	<0.1%	0%	<0.1%
9	LaunchDarkly	<0.1%	<0.1%	<0.1%	0%	<0.1%	0%	<0.1%
10	Statsig	0%	<0.1%	<0.1%	0%	0%	0%	0%

By site popularity

Share of measured sites in each Tranco popularity band that use the technology: the top 1,000, 10,000 and 100,000 sites and the whole top million.

#	Technology	Top 10K	Top 100K	Top 1M
1	VWO	3%	3.4%	1.5%
2	Adobe Target	3%	0.5%	<0.1%
3	AB Tasty	1.5%	1.1%	0.6%
4	Kameleoon	1.5%	0.4%	0.1%
5	Convert	0%	0.5%	0.8%
6	Optimizely	0%	1.4%	0.5%
7	Google Optimize (retired)	0%	0.5%	0.3%
8	GrowthBook	0%	0%	<0.1%
9	LaunchDarkly	0%	0.1%	<0.1%
	Sites measured	66	931	11,909

Popular sites vs local business websites

Popular: sites of United Kingdom from the Tranco top million. Local business: websites of companies with 1–20 locations in the country, taken from a business places directory (platforms, marketplaces and aggregators excluded).

#	Technology	Popular sites	Local business	Difference, pp
	Any A/B testing	3.7%	0.3%	−3.4
1	VWO	1.5%	0.1%	−1.4
2	AB Tasty	0.6%	<0.1%	−0.5
3	Convert	0.8%	<0.1%	−0.7
4	Optimizely	0.5%	<0.1%	−0.4
5	Google Optimize (retired)	0.3%	<0.1%	−0.2
6	Kameleoon	0.1%	<0.1%	−0.1
7	Adobe Target	<0.1%	0%	−0.1
8	GrowthBook	<0.1%	0%	−0.1
9	LaunchDarkly	<0.1%	0%	0
	Sites measured	11,909	21,114

Our crawler: 11,909 sites · United Kingdom · updated 23 Oct 2026 · Methodology