Which do the most popular websites prefer?

Among the 710 sites of the top 1,000 that we could read, 9 (1.3%) use VWO and 10 (1.4%) use Optimizely.

Can a website use both VWO and Optimizely?

Yes: 0 of the 7,859 sites show both (<0.1%); 142 show only VWO and 91 only Optimizely.

Comparison · A/B testing

As of 2026-10-02, VWO is detected on 142 of 7,859 popular websites (1.8%) and Optimizely on 91 (1.2%): VWO is 1.6x as common. 0 sites use both.

	VWO	Optimizely
Sites using it	142	91
Share of 7,859 sites	1.8%	1.2%
Share of the top 1,000 sites (710 readable)	1.3%	1.4%
Only this one of the two	142	91

Both: 0 sites. Detected on 2026-10-02 from the home page; a technology that leaves no trace there is not counted.

Sector	Sites	VWO	Optimizely
Other	6,305	1.9%	1.2%
News	347	0.9%	1.2%
Entertainment	314	0.6%	<0.1%
Education	246	1.2%	0.8%
Government	241	0.4%	<0.1%
Technology	133	3.0%	3.8%
Finance	97	4.1%	2.1%
E-commerce	93	4.3%	<0.1%

Share of the sector's sites using each technology; sectors with at least 50 sites.

TLD	Sites	VWO	Optimizely
.com	4,138	2.6%	1.8%
.org	437	2.1%	1.6%
.net	333	0.9%	0.3%
.ru	258	<0.1%	<0.1%
.jp	189	0.5%	<0.1%
.io	185	1.6%	<0.1%
.de	180	0.6%	<0.1%
.edu	159	0.6%	0.6%
.gov	110	<0.1%	<0.1%

Top-level domains with at least 100 sites.

Which is more popular, VWO or Optimizely?: As of 2026-10-02, VWO is detected on 142 of 7,859 popular websites (1.8%) and Optimizely on 91 (1.2%): VWO is 1.6x as common. 0 sites use both.
Which do the most popular websites prefer?: Among the 710 sites of the top 1,000 that we could read, 9 (1.3%) use VWO and 10 (1.4%) use Optimizely.
Can a website use both VWO and Optimizely?: Yes: 0 of the 7,859 sites show both (<0.1%); 142 show only VWO and 91 only Optimizely.