1
At a glance the headline numbers for Email marketing impact
Performance impact by email_marketing provider.
5
Providers ranked
After min-sites filter
9,785
Sites in sample
Combined across all items
0.04
Best CLS (p75)
Klaviyo
The State of Web Vitals · Q2 2026 · 189,915 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 | 89.0% | 2,917 | |
| 2 | Mailchimp | 0.04 | 86.8% | 3,286 | |
| 3 | ActiveCampaign | 0.06 | 84.6% | 441 | |
| 4 | HubSpot | 0.06 | 83.7% | 3,078 | |
| 5 | Salesforce Marketing Cloud | 0.10 | 77.8% | 63 |
The State of Web Vitals · Q2 2026 · 189,915 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% 20 0.06
Klaviyo 1.5% 2,917 0.04
Mailchimp 1.7% 3,286 0.04
ActiveCampaign 0.2% 441 0.06
HubSpot 1.6% 3,078 0.06
Salesforce Marketing Cloud 0% 63 0.10
Marketo 0% 40 0.11
Iterable 0% 8 0.31
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 · Q2 2026 · 189,915 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
Klaviyo 1.5%
882.0s
93145ms
890.04
861.4s
81691ms
Mailchimp 1.7%
772.4s
98104ms
870.04
702.0s
491.5s
ActiveCampaign 0.2%
702.7s
96120ms
850.06
632.2s
401.7s
HubSpot 1.6%
792.3s
97110ms
840.06
731.9s
541.3s
Salesforce Marketing Cloud 0%
752.5s
74204ms
780.10
632.1s
371.5s
Braze 0%
652.7s
85183ms
900.06
452.2s
301.5s
Marketo 0%
802.3s
97120ms
680.11
751.8s
551.2s
Iterable 0%
881.5s
88152ms
630.31
881.2s
88659ms
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 84%. computed
The State of Web Vitals · Q2 2026 · 189,915 sites · all devices field datacorewebvitals.io/state-of-cwv
Related signals Font services (4) → Session recording (11) → CMS (17) → Search (6) → Chrome field data from 189,915 sites, representing millions of real page loads · How we measured
Chrome field data from 189,915 sites, representing millions of real page loads. How we measured.