A/B testing impact React sites

Performance impact by ab_testing provider.

Field data PhoneDesktopAll Scope All sites October 2026 edition · Phone field outcomes · React sites only
Metric LCP INP CLS
React Scoped to 9,570 sites out of 210,902 analyzed (frameworks) Compare with all sites →
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
139ms
Best INP (p75)
Google Optimize
The State of Web Vitals · October 2026 · React sites (9,570) · phone field datacorewebvitals.io/state-of-cwv
2

The ranking sorted by INP at p75, fastest first

# Provider INP p75 Passing Sites
1 Google Optimize 139ms 90.9%
745
The State of Web Vitals · October 2026 · React sites (9,570) · phone field datacorewebvitals.io/state-of-cwv
3

Passing INP per provider which group passes the INP most often

ProviderSitesPassing INPp75
Convert 0.1% 6 100% 157ms
Google Optimize 7.8% 745 91% 139ms
Kameleoon 0.1% 7 86% 176ms
VWO 0.1% 14 77% 195ms
Optimizely 0.2% 19 63% 217ms
LaunchDarkly 0.1% 9 33% 563ms
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good INP (200ms at p75) · one value per site
The State of Web Vitals · October 2026 · React sites (9,570) · 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 7.8%
782.3s
91139ms
910.02
741.8s
581.3s
Optimizely 0.2%
772.2s
63217ms
940.07
592.0s
291.2s
VWO 0.1%
692.5s
77195ms
850.04
851.7s
62942ms
LaunchDarkly 0.1%
05.6s
33563ms
330.42
03.2s
02.0s
Kameleoon 0.1%
862.2s
86176ms
860.03
572.0s
431.5s
Convert 0.1%
503.4s
100157ms
500.20
672.7s
331.6s
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) · phone 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