A/B testing impact: 8 providers ranked | The State of Web Vitals 2026

LCP INP CLS

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

Performance impact by ab_testing provider.

Providers ranked

After min-sites filter

21,106

Sites in sample

Combined across all items

0.10

Best CLS (p75)

VWO

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv

The ranking sorted by CLS at p75, fastest first

#	Provider	CLS p75	Passing	Sites
1	VWO	0.10	77.5%	433
2	Google Optimize	0.10	75.9%	19,928
3	Kameleoon	0.12	72.5%	112
4	AB Tasty	0.13	70.3%	109
5	Convert	0.13	70.2%	191
6	Dynamic Yield	0.13	64.0%	65
7	Optimizely	0.13	70.2%	137
8	LaunchDarkly	0.29	63.9%	131

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75

VWO 0.2% 433 78% 0.10

Monetate 0% 26 77% 0.08

Google Optimize 10.5% 19,928 76% 0.10

Kameleoon 0.1% 112 73% 0.12

AB Tasty 0.1% 109 70% 0.13

Convert 0.1% 191 70% 0.13

Optimizely 0.1% 137 70% 0.13

Dynamic Yield 0% 65 64% 0.13

LaunchDarkly 0.1% 131 64% 0.29

Split.io 0% 9 50% 0.33

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

78% of VWO sites pass CLS. LaunchDarkly trails 14 points behind, leaving 36% of its sites failing. computed

The State of Web Vitals · Q2 2026 · 189,915 sites · desktop field datacorewebvitals.io/state-of-cwv

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%

852.0s

9961ms

760.10

811.6s

581.2s

VWO 0.2%

822.3s

9896ms

780.10

771.7s

541.2s

Convert 0.1%

742.5s

99108ms

700.13

702.0s

561.5s

Optimizely 0.1%

732.7s

92122ms

700.13

751.8s

591.1s

LaunchDarkly 0.1%

543.3s

81128ms

640.29

572.6s

73815ms

Kameleoon 0.1%

822.1s

95118ms

730.12

851.6s

531.1s

AB Tasty 0.1%

842.1s

9793ms

700.13

841.5s

71870ms

Dynamic Yield 0%

782.2s

83188ms

640.13

761.5s

68985ms

Monetate 0%

852.1s

96138ms

770.08

921.6s

621.1s

Split.io 0%

333.4s

80128ms

500.33

332.6s

671.8s

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.

VWO leads on CLS: 78% of its sites pass. LaunchDarkly trails at 64%. computed

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