The State of Web Vitals

A/B testing impact

Performance impact by ab_testing provider.

Field data PhoneDesktopAll Scope All sites Q2 2026 edition · Phone field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for A/B testing impact

Performance impact by ab_testing provider.

8
Providers ranked
After min-sites filter
21,106
Sites in sample
Combined across all items
0.03
Best CLS (p75)
Google Optimize
The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by CLS at p75, fastest first

# Provider CLS p75 Passing Sites
1 Google Optimize 0.03 87.1%
19,928
2 VWO 0.05 82.5%
433
3 Convert 0.07 80.2%
191
4 Kameleoon 0.07 76.7%
112
5 Optimizely 0.09 78.4%
137
6 AB Tasty 0.12 72.2%
109
7 LaunchDarkly 0.13 70.8%
131
8 Dynamic Yield 0.21 63.6%
65
The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
3

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75
Google Optimize 10.5% 19,928 87% 0.03
VWO 0.2% 433 83% 0.05
Convert 0.1% 191 80% 0.07
Optimizely 0.1% 137 78% 0.09
Monetate 0% 26 78% 0.06
Kameleoon 0.1% 112 77% 0.07
AB Tasty 0.1% 109 72% 0.12
LaunchDarkly 0.1% 131 71% 0.13
Dynamic Yield 0% 65 64% 0.21
Split.io 0% 9 43% 0.20
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good CLS (0.1 at p75) · one value per site

87% of Google Optimize sites pass CLS. LaunchDarkly trails 16 points behind, leaving 29% of its sites failing. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
4

All five vitals at once the whole category without toggling - cell is the pass rate, small number the p75

LCP
INP
CLS
FCP
TTFB
Google Optimize 10.5%
812.3s
94125ms
870.03
731.9s
541.3s
VWO 0.2%
762.4s
74204ms
830.05
692.0s
531.3s
Convert 0.1%
672.7s
77197ms
800.07
692.1s
511.5s
Optimizely 0.1%
682.9s
61239ms
780.09
612.2s
441.2s
LaunchDarkly 0.1%
454.1s
67254ms
710.13
453.0s
541.2s
Kameleoon 0.1%
772.4s
62242ms
770.07
701.9s
531.1s
AB Tasty 0.1%
782.2s
76194ms
720.12
731.8s
56927ms
Dynamic Yield 0%
662.7s
40322ms
640.21
711.9s
631.1s
Monetate 0%
782.4s
45232ms
780.06
701.9s
391.1s
Split.io 0%
573.2s
50283ms
430.20
432.6s
571.2s
60%95%+ passing Cell: pass rate, small number = p75 · faded rows: under 100 sites

One row per provider, one column per vital - the cell is the share of sites passing, the small number the p75. No toggling needed to see where the category actually differs.

Google Optimize leads on CLS: 87% of its sites pass. LaunchDarkly trails at 71%. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · phone field datacorewebvitals.io/state-of-cwv
Related signals Maps (4) → CDN (15) → Chat & messaging (17) → Bot detection (7) → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured