1
At a glance the headline numbers for A/B testing impact
Performance impact by ab_testing provider.
1
Providers ranked
After min-sites filter
745
Sites in sample
Combined across all items
2.2s
Best LCP (p75)
Google Optimize
The State of Web Vitals · October 2026 · React sites (9,570) · 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 | 80.3% | 745 |
The State of Web Vitals · October 2026 · React sites (9,570) · all devices field datacorewebvitals.io/state-of-cwv
3
Passing LCP per provider which group passes the LCP most often
ProviderSitesPassing LCPp75
Kameleoon 0.1% 7 2.3s
Optimizely 0.2% 19 2.1s
Google Optimize 7.8% 745 2.2s
VWO 0.1% 14 2.6s
Convert 0.1% 6 3.1s
LaunchDarkly 0.1% 9 5.5s
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
The State of Web Vitals · October 2026 · React sites (9,570) · 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 7.8%
802.2s
92121ms
910.03
761.8s
591.3s
Optimizely 0.2%
842.1s
94170ms
900.07
631.9s
321.0s
VWO 0.1%
572.6s
79191ms
860.05
711.8s
50952ms
LaunchDarkly 0.1%
135.5s
75308ms
500.21
03.1s
132.0s
Kameleoon 0.1%
862.3s
100161ms
570.13
432.0s
431.6s
Convert 0.1%
503.1s
100135ms
500.33
672.2s
331.5s
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.
The State of Web Vitals · October 2026 · React sites (9,570) · all devices field datacorewebvitals.io/state-of-cwv
Related signals Maps (4) → CDN (16) → Chat & messaging (17) → Bot detection (8) → 210,902 crawled sites with Chrome field data, representing millions of real page loads · How we measured
210,902 crawled sites with Chrome field data, representing millions of real page loads. How we measured.