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

22,448

Sites in sample

Combined across all items

0.03

Best CLS (p75)

Google Optimize

The State of Web Vitals · October 2026 · 210,902 crawled sites · phone field datacorewebvitals.io/state-of-cwv

The ranking sorted by CLS at p75, fastest first

#	Provider	CLS p75	Passing	Sites
1	Google Optimize	0.03	87.2%	21,150
2	VWO	0.05	81.9%	475
3	Convert	0.06	82.2%	210
4	Kameleoon	0.06	77.5%	129
5	Optimizely	0.11	74.8%	157
6	LaunchDarkly	0.12	71.9%	141
7	AB Tasty	0.13	71.1%	117
8	Dynamic Yield	0.19	66.1%	69

The State of Web Vitals · October 2026 · 210,902 crawled sites · phone field datacorewebvitals.io/state-of-cwv

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75

Google Optimize 10% 21,150 87% 0.03

Convert 0.1% 210 82% 0.06

VWO 0.2% 475 82% 0.05

Monetate 0% 28 79% 0.06

Kameleoon 0.1% 129 78% 0.06

Optimizely 0.1% 157 75% 0.11

LaunchDarkly 0.1% 141 72% 0.12

AB Tasty 0.1% 117 71% 0.13

Dynamic Yield 0% 69 66% 0.19

Split.io 0% 9 43% 0.20

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

87% of Google Optimize sites pass CLS. AB Tasty trails 16 points behind, leaving 29% of its sites failing. computed

The State of Web Vitals · October 2026 · 210,902 crawled sites · phone 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%

812.3s

93126ms

870.03

731.9s

541.3s

VWO 0.2%

772.4s

74203ms

820.05

692.0s

531.2s

Convert 0.1%

692.7s

78195ms

820.06

702.0s

521.4s

Optimizely 0.1%

662.9s

63235ms

750.11

612.1s

441.2s

LaunchDarkly 0.1%

474.0s

67245ms

720.12

473.0s

521.3s

Kameleoon 0.1%

762.5s

63229ms

780.06

701.9s

541.1s

AB Tasty 0.1%

762.4s

74206ms

710.13

721.8s

56949ms

Dynamic Yield 0%

682.7s

42313ms

660.19

711.9s

641.0s

Monetate 0%

792.4s

48230ms

790.06

711.9s

421.0s

Split.io 0%

573.2s

50283ms

430.20

432.6s

571.2s

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 CLS: 87% of its sites pass. AB Tasty trails at 71%. computed

The State of Web Vitals · October 2026 · 210,902 crawled sites · 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