1
At a glance the headline numbers for Email marketing impact
Performance impact by email_marketing provider.
4
Providers ranked
After min-sites filter
5,151
Sites in sample
Combined across all items
0.04
Best CLS (p75)
Klaviyo
The State of Web Vitals · Q1 2026 · 94,910 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 | 89.3% | 1,520 | |
| 2 | Mailchimp | 0.04 | 87.1% | 1,748 | |
| 3 | HubSpot | 0.05 | 84.8% | 1,645 | |
| 4 | ActiveCampaign | 0.06 | 86.4% | 238 |
The State of Web Vitals · Q1 2026 · 94,910 sites · all devices field datacorewebvitals.io/state-of-cwv
3
Passing CLS per provider which group passes the CLS most often
ProviderSitesPassing CLSp75
Braze 0% 12 0.05
Klaviyo 1.6% 1,520 0.04
Mailchimp 1.8% 1,748 0.04
Salesforce Marketing Cloud 0% 30 0.09
ActiveCampaign 0.3% 238 0.06
HubSpot 1.7% 1,645 0.05
Marketo 0% 22 0.11
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
No provider stands out: pass rates sit between 85% and 89%. computed
The State of Web Vitals · Q1 2026 · 94,910 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 1.8%
772.4s
98105ms
870.04
702.0s
481.5s
HubSpot 1.7%
812.3s
97110ms
850.05
751.8s
541.2s
Klaviyo 1.6%
882.0s
92145ms
890.04
861.4s
81692ms
ActiveCampaign 0.3%
702.7s
96121ms
860.06
662.2s
411.7s
Salesforce Marketing Cloud 0%
702.6s
83170ms
870.09
672.2s
501.7s
Marketo 0%
772.3s
95132ms
730.11
771.7s
591.2s
Braze 0%
672.8s
75195ms
1000.05
422.2s
331.5s
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. HubSpot trails at 85%. computed
The State of Web Vitals · Q1 2026 · 94,910 sites · all devices field datacorewebvitals.io/state-of-cwv
Related signals Font services (4) → Session recording (11) → Search (4) → Performance services (8) → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.