A/B testing impact

Performance impact by ab_testing provider.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Desktop field outcomes
Metric LCP INP CLS
1

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

Performance impact by ab_testing provider.

7
Providers ranked
After min-sites filter
11,168
Sites in sample
Combined across all items
2.0s
Best LCP (p75)
Kameleoon
The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by LCP at p75, fastest first

# Provider LCP p75 Passing Sites
1 Kameleoon 2.0s 83.6%
60
2 Google Optimize 2.0s 85.8%
10,546
3 AB Tasty 2.1s 77.3%
53
4 VWO 2.3s 79.6%
246
5 Convert 2.5s 75.6%
105
6 Optimizely 2.8s 70.3%
82
7 LaunchDarkly 3.5s 54.8%
76
The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
3

Passing LCP per provider which group passes the LCP most often

ProviderSitesPassing LCPp75
Google Optimize 11.1% 10,546 86% 2.0s
Monetate 0% 13 85% 2.1s
Kameleoon 0.1% 60 84% 2.0s
VWO 0.3% 246 80% 2.3s
AB Tasty 0.1% 53 77% 2.1s
Convert 0.1% 105 76% 2.5s
Optimizely 0.1% 82 70% 2.8s
Dynamic Yield 0% 37 70% 2.7s
Split.io 0% 5 67% 2.7s
LaunchDarkly 0.1% 76 55% 3.5s
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good LCP (2.5s at p75) · one value per site

86% of Google Optimize sites pass LCP. Convert trails 10 points behind. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop 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 11.1%
862.0s
9961ms
760.10
811.6s
591.2s
VWO 0.3%
802.3s
9896ms
790.09
771.7s
521.1s
Convert 0.1%
762.5s
100101ms
660.15
722.0s
601.5s
Optimizely 0.1%
702.8s
89122ms
680.15
731.9s
601.1s
LaunchDarkly 0.1%
553.5s
81127ms
640.23
582.7s
75786ms
Kameleoon 0.1%
842.0s
94117ms
800.09
861.6s
491.1s
AB Tasty 0.1%
772.1s
9895ms
640.15
801.5s
72815ms
Dynamic Yield 0%
702.7s
82195ms
600.19
671.9s
571.4s
Monetate 0%
852.1s
100119ms
850.06
851.7s
461.4s
Split.io 0%
672.7s
67185ms
330.43
671.6s
100324ms
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 LCP: 86% of its sites pass. Convert trails at 76%. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv
Related signals Maps (4) → CDN (15) → Chat & messaging (16) → Bot detection (7) → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured