A/B testing impact

Performance impact by ab_testing provider.

Field data PhoneDesktopAll Scope All sites Q1 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.

7
Providers ranked
After min-sites filter
11,168
Sites in sample
Combined across all items
2.2s
Best LCP (p75)
Google Optimize
The State of Web Vitals · Q1 2026 · 94,910 sites · all devices field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by LCP at p75, fastest first

# Provider LCP p75 Passing Sites
1 Google Optimize 2.2s 82.3%
10,546
2 AB Tasty 2.3s 81.6%
53
3 Kameleoon 2.4s 75.0%
60
4 VWO 2.4s 77.3%
246
5 Convert 2.7s 67.6%
105
6 Optimizely 2.9s 65.0%
82
7 LaunchDarkly 3.7s 48.6%
76
The State of Web Vitals · Q1 2026 · 94,910 sites · all devices field datacorewebvitals.io/state-of-cwv
3

Passing LCP per provider which group passes the LCP most often

ProviderSitesPassing LCPp75
Monetate 0% 13 92% 2.2s
Google Optimize 11.1% 10,546 82% 2.2s
AB Tasty 0.1% 53 82% 2.3s
VWO 0.3% 246 77% 2.4s
Kameleoon 0.1% 60 75% 2.4s
Convert 0.1% 105 68% 2.7s
Dynamic Yield 0% 37 66% 2.9s
Optimizely 0.1% 82 65% 2.9s
Split.io 0% 5 60% 3.3s
LaunchDarkly 0.1% 76 49% 3.7s
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

82% of Google Optimize sites pass LCP. Convert trails 14 points behind, leaving 32% of its sites failing. computed

The State of Web Vitals · Q1 2026 · 94,910 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 11.1%
822.2s
96104ms
860.05
761.8s
551.3s
VWO 0.3%
772.4s
80190ms
840.04
731.9s
541.1s
Convert 0.1%
682.7s
85184ms
770.10
761.8s
571.5s
Optimizely 0.1%
652.9s
72214ms
790.09
652.2s
501.2s
LaunchDarkly 0.1%
493.7s
72233ms
710.20
522.5s
601.1s
Kameleoon 0.1%
752.4s
68208ms
730.11
751.8s
501.1s
AB Tasty 0.1%
822.3s
88169ms
690.12
761.8s
67852ms
Dynamic Yield 0%
662.9s
57297ms
630.18
662.1s
541.2s
Monetate 0%
922.2s
85170ms
770.08
851.7s
391.4s
Split.io 0%
603.3s
80185ms
400.34
602.6s
80579ms
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: 82% of its sites pass. Convert trails at 68%. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · all devices 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