1
At a glance the headline numbers for Email marketing impact
Performance impact by email_marketing provider.
5
Providers ranked
After min-sites filter
11,055
Sites in sample
Combined across all items
0.04
Best CLS (p75)
Klaviyo
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 | Klaviyo | 0.04 | 89.2% | 3,321 | |
| 2 | Mailchimp | 0.04 | 86.9% | 3,680 | |
| 3 | ActiveCampaign | 0.06 | 84.2% | 495 | |
| 4 | HubSpot | 0.06 | 83.5% | 3,494 | |
| 5 | Salesforce Marketing Cloud | 0.10 | 78.5% | 65 |
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
Klaviyo 1.6% 3,321 0.04
Mailchimp 1.7% 3,680 0.04
ActiveCampaign 0.2% 495 0.06
HubSpot 1.6% 3,494 0.06
Braze 0% 25 0.09
Salesforce Marketing Cloud 0% 65 0.10
Marketo 0% 43 0.11
Iterable 0% 8 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
89% of Klaviyo sites pass CLS. HubSpot trails 5 points behind. 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
Mailchimp 1.7%
772.4s
98104ms
870.04
702.0s
491.6s
HubSpot 1.6%
792.4s
97110ms
840.06
731.9s
541.3s
Klaviyo 1.6%
882.0s
93146ms
890.04
861.4s
81686ms
ActiveCampaign 0.2%
712.7s
96121ms
840.06
642.2s
421.7s
Salesforce Marketing Cloud 0%
752.5s
73204ms
790.10
652.1s
371.5s
Marketo 0%
812.3s
98117ms
670.11
771.7s
541.2s
Braze 0%
682.7s
84187ms
800.09
482.2s
361.5s
Iterable 0%
881.6s
88157ms
630.34
881.3s
88683ms
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.
Klaviyo leads on CLS: 89% of its sites pass. ActiveCampaign trails at 84%. computed
The State of Web Vitals · November 2026 · 213,971 crawled sites · all devices field datacorewebvitals.io/state-of-cwv
Related signals Font services (4) → Session recording (11) → CMS (17) → Search (6) → 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.