The State of Web Vitals

A/B testing impact

Performance impact by ab_testing provider.

Field data PhoneDesktopAll Scope All sites Q2 2026 edition · All devices 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
0.05
Best CLS (p75)
VWO
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by CLS at p75, fastest first

# Provider CLS p75 Passing Sites
1 VWO 0.05 83.8%
433
2 Google Optimize 0.05 86.1%
19,928
3 Convert 0.08 79.9%
191
4 Optimizely 0.09 80.0%
137
5 LaunchDarkly 0.11 72.7%
131
6 AB Tasty 0.12 72.1%
109
7 Kameleoon 0.12 70.9%
112
8 Dynamic Yield 0.19 63.5%
65
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices 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 86% 0.05
VWO 0.2% 433 84% 0.05
Optimizely 0.1% 137 80% 0.09
Convert 0.1% 191 80% 0.08
Monetate 0% 26 77% 0.08
LaunchDarkly 0.1% 131 73% 0.11
AB Tasty 0.1% 109 72% 0.12
Kameleoon 0.1% 112 71% 0.12
Dynamic Yield 0% 65 64% 0.19
Split.io 0% 9 44% 0.34
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

86% of Google Optimize sites pass CLS. Kameleoon trails 15 points behind, leaving 29% of its sites failing. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · all devices 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%
822.2s
96104ms
860.05
751.8s
551.3s
VWO 0.2%
782.4s
80179ms
840.05
721.9s
551.2s
Convert 0.1%
702.7s
86182ms
800.08
751.9s
551.4s
Optimizely 0.1%
692.7s
73205ms
800.09
642.2s
461.3s
LaunchDarkly 0.1%
493.9s
76197ms
730.11
492.7s
551.2s
Kameleoon 0.1%
772.4s
71210ms
710.12
721.9s
531.1s
AB Tasty 0.1%
782.3s
86169ms
720.12
711.9s
61988ms
Dynamic Yield 0%
702.6s
47295ms
640.19
751.8s
61967ms
Monetate 0%
892.3s
71214ms
770.08
771.7s
391.0s
Split.io 0%
333.3s
63267ms
440.34
442.6s
56884ms
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: 86% of its sites pass. Kameleoon trails at 71%. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · all devices 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