1
At a glance the headline numbers for A/B testing impact
Performance impact by ab_testing provider.
8
Providers ranked
After min-sites filter
22,660
Sites in sample
Combined across all items
0.05
Best CLS (p75)
VWO
The State of Web Vitals · November 2026 · 213,971 crawled sites · all devices field datacorewebvitals.io/state-of-cwv
2
The ranking sorted by CLS at p75, fastest first
| # | Provider | CLS p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | VWO | 0.05 | 83.4% | 485 | |
| 2 | Google Optimize | 0.05 | 86.1% | 21,342 | |
| 3 | Convert | 0.07 | 81.2% | 214 | |
| 4 | Optimizely | 0.10 | 76.8% | 157 | |
| 5 | LaunchDarkly | 0.11 | 74.3% | 143 | |
| 6 | AB Tasty | 0.12 | 71.9% | 119 | |
| 7 | Kameleoon | 0.12 | 71.3% | 131 | |
| 8 | Dynamic Yield | 0.18 | 65.7% | 69 |
The State of Web Vitals · November 2026 · 213,971 crawled sites · all devices field datacorewebvitals.io/state-of-cwv
3
Passing CLS per provider which group passes the CLS most often
ProviderSitesPassing CLSp75
Google Optimize 10% 21,342 0.05
VWO 0.2% 485 0.05
Convert 0.1% 214 0.07
Optimizely 0.1% 157 0.10
Monetate 0% 28 0.10
LaunchDarkly 0.1% 143 0.11
AB Tasty 0.1% 119 0.12
Kameleoon 0.1% 131 0.12
Dynamic Yield 0% 69 0.18
Split.io 0% 9 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. Kameleoon trails 15 points behind, leaving 29% of its sites failing. computed
The State of Web Vitals · November 2026 · 213,971 crawled sites · all devices field datacorewebvitals.io/state-of-cwv
4
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%
822.2s
96104ms
860.05
751.8s
551.3s
VWO 0.2%
782.4s
81180ms
830.05
721.9s
561.1s
Convert 0.1%
722.6s
86182ms
810.07
751.8s
571.3s
Optimizely 0.1%
702.7s
75203ms
770.10
652.2s
471.3s
LaunchDarkly 0.1%
513.8s
77195ms
740.11
512.7s
531.3s
Kameleoon 0.1%
772.4s
74205ms
710.12
711.9s
541.1s
AB Tasty 0.1%
772.4s
84169ms
720.12
721.9s
611.0s
Dynamic Yield 0%
722.6s
49287ms
660.18
751.8s
62963ms
Monetate 0%
862.3s
73209ms
750.10
791.7s
431.0s
Split.io 0%
333.3s
63267ms
440.34
442.6s
56884ms
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. Kameleoon trails at 71%. computed
The State of Web Vitals · November 2026 · 213,971 crawled sites · all devices 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
213,971 crawled sites with Chrome field data, representing millions of real page loads. How we measured.