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
0.02
Best CLS (p75)
Mailchimp
The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
2
The ranking sorted by CLS at p75, fastest first
| # | Provider | CLS p75 | Passing | Sites | |
|---|---|---|---|---|---|
| 1 | Mailchimp | 0.02 | 88.8% | 1,748 | |
| 2 | HubSpot | 0.03 | 86.7% | 1,645 | |
| 3 | Klaviyo | 0.04 | 90.1% | 1,520 | |
| 4 | ActiveCampaign | 0.06 | 86.1% | 238 |
The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
3
Passing CLS per provider which group passes the CLS most often
ProviderSitesPassing CLSp75
Braze 0% 12 0.08
Klaviyo 1.6% 1,520 0.04
Mailchimp 1.8% 1,748 0.02
HubSpot 1.7% 1,645 0.03
Salesforce Marketing Cloud 0% 30 0.06
ActiveCampaign 0.3% 238 0.06
Marketo 0% 22 0.02
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 86% and 90%. computed
The State of Web Vitals · Q1 2026 · 94,910 sites · phone 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%
762.5s
97122ms
890.02
702.0s
491.5s
HubSpot 1.7%
772.4s
93134ms
870.03
701.9s
511.3s
Klaviyo 1.6%
872.0s
89164ms
900.04
851.5s
81708ms
ActiveCampaign 0.3%
702.7s
93150ms
860.06
652.2s
451.5s
Salesforce Marketing Cloud 0%
722.5s
76189ms
860.06
692.2s
481.5s
Marketo 0%
772.3s
95163ms
820.02
771.8s
551.2s
Braze 0%
732.5s
82179ms
1000.08
462.0s
361.4s
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: 90% of its sites pass. ActiveCampaign trails at 86%. computed
The State of Web Vitals · Q1 2026 · 94,910 sites · phone 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.