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

22,660

Sites in sample

Combined across all items

0.10

Best CLS (p75)

VWO

The State of Web Vitals · November 2026 · 213,971 crawled 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	77.8%	485
2	Google Optimize	0.10	76.0%	21,342
3	Convert	0.11	72.9%	214
4	AB Tasty	0.11	72.0%	119
5	Kameleoon	0.12	72.5%	131
6	Dynamic Yield	0.13	64.8%	69
7	Optimizely	0.14	68.1%	157
8	LaunchDarkly	0.28	65.8%	143

The State of Web Vitals · November 2026 · 213,971 crawled sites · desktop field datacorewebvitals.io/state-of-cwv

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75

VWO 0.2% 485 78% 0.10

Monetate 0% 28 78% 0.07

Google Optimize 10% 21,342 76% 0.10

Convert 0.1% 214 73% 0.11

Kameleoon 0.1% 131 73% 0.12

AB Tasty 0.1% 119 72% 0.11

Optimizely 0.1% 157 68% 0.14

LaunchDarkly 0.1% 143 66% 0.28

Dynamic Yield 0% 69 65% 0.13

Split.io 0% 9 50% 0.32

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 12 points behind, leaving 34% of its sites failing. computed

The State of Web Vitals · November 2026 · 213,971 crawled 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%

862.0s

9962ms

760.10

811.6s

581.2s

VWO 0.2%

822.3s

9898ms

780.10

771.7s

561.2s

Convert 0.1%

762.5s

98106ms

730.11

722.0s

581.4s

Optimizely 0.1%

742.7s

92122ms

680.14

761.8s

611.1s

LaunchDarkly 0.1%

563.3s

82127ms

660.28

582.6s

72873ms

Kameleoon 0.1%

822.1s

95117ms

730.12

851.6s

551.1s

AB Tasty 0.1%

822.1s

9694ms

720.11

831.5s

69905ms

Dynamic Yield 0%

802.2s

84178ms

650.13

781.5s

70901ms

Monetate 0%

852.1s

96135ms

780.07

931.6s

631.1s

Split.io 0%

333.4s

80128ms

500.32

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 66%. computed

The State of Web Vitals · November 2026 · 213,971 crawled sites · desktop field datacorewebvitals.io/state-of-cwv

Related signals Maps (4) → CDN (16) → Chat & messaging (17) → Bot detection (8) → 213,971 crawled sites with Chrome field data, representing millions of real page loads · How we measured