A/B testing impact: 7 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

11,168

Sites in sample

Combined across all items

0.09

Best CLS (p75)

Kameleoon

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv

The ranking sorted by CLS at p75, fastest first

#	Provider	CLS p75	Passing	Sites
1	Kameleoon	0.09	80.0%	60
2	VWO	0.09	78.5%	246
3	Google Optimize	0.10	76.2%	10,546
4	Optimizely	0.15	68.0%	82
5	Convert	0.15	65.6%	105
6	AB Tasty	0.15	63.6%	53
7	LaunchDarkly	0.23	64.4%	76

The State of Web Vitals · Q1 2026 · 94,910 sites · desktop field datacorewebvitals.io/state-of-cwv

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75

Monetate 0% 13 85% 0.06

Kameleoon 0.1% 60 80% 0.09

VWO 0.3% 246 79% 0.09

Google Optimize 11.1% 10,546 76% 0.10

Optimizely 0.1% 82 68% 0.15

Convert 0.1% 105 66% 0.15

LaunchDarkly 0.1% 76 64% 0.23

AB Tasty 0.1% 53 64% 0.15

Dynamic Yield 0% 37 60% 0.19

Split.io 0% 5 33% 0.43

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

79% of VWO sites pass CLS. Convert trails 13 points behind, leaving 34% of its sites failing. computed

The State of Web Vitals · Q1 2026 · 94,910 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 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.

VWO leads on CLS: 79% of its sites pass. Convert trails at 66%. 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