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

0.04

Best CLS (p75)

VWO

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

The ranking sorted by CLS at p75, fastest first

#	Provider	CLS p75	Passing	Sites
1	VWO	0.04	83.5%	246
2	Google Optimize	0.05	86.1%	10,546
3	Optimizely	0.09	79.0%	82
4	Convert	0.10	76.5%	105
5	Kameleoon	0.11	73.3%	60
6	AB Tasty	0.12	69.4%	53
7	LaunchDarkly	0.20	70.7%	76

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

Passing CLS per provider which group passes the CLS most often

ProviderSitesPassing CLSp75

Google Optimize 11.1% 10,546 86% 0.05

VWO 0.3% 246 84% 0.04

Optimizely 0.1% 82 79% 0.09

Monetate 0% 13 77% 0.08

Convert 0.1% 105 77% 0.10

Kameleoon 0.1% 60 73% 0.11

LaunchDarkly 0.1% 76 71% 0.20

AB Tasty 0.1% 53 69% 0.12

Dynamic Yield 0% 37 63% 0.18

Split.io 0% 5 40% 0.34

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

86% of Google Optimize sites pass CLS. Convert trails 9 points behind. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · all devices 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%

822.2s

96104ms

860.05

761.8s

551.3s

VWO 0.3%

772.4s

80190ms

840.04

731.9s

541.1s

Convert 0.1%

682.7s

85184ms

770.10

761.8s

571.5s

Optimizely 0.1%

652.9s

72214ms

790.09

652.2s

501.2s

LaunchDarkly 0.1%

493.7s

72233ms

710.20

522.5s

601.1s

Kameleoon 0.1%

752.4s

68208ms

730.11

751.8s

501.1s

AB Tasty 0.1%

822.3s

88169ms

690.12

761.8s

67852ms

Dynamic Yield 0%

662.9s

57297ms

630.18

662.1s

541.2s

Monetate 0%

922.2s

85170ms

770.08

851.7s

391.4s

Split.io 0%

603.3s

80185ms

400.34

602.6s

80579ms

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: 86% of its sites pass. Convert trails at 77%. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · all devices 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