Customer.io vs Klaviyo
Head-to-head usage across the sites we track.
Top sites by authority
Customer.io · Klaviyo · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
1
20
Open Page Rank 8+
18
117
Open Page Rank 7+
68
471
Open Page Rank 6+
117
1,263
Open Page Rank 5+
181
3,084
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Customer.io · Klaviyo · share of sites in each country using one or the other
United States
868
94,628
United Kingdom
489
37,132
Canada
467
29,501
Australia
363
27,110
Germany
405
23,957
France
370
20,942
India
564
19,705
Spain
346
16,472
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Customer.io | Klaviyo |
|---|---|---|
| LCP | 2.4 s | 1.6 s |
| INP | 125 ms | 100 ms |
| CLS | 0 | 0 |
| TTFB | 800 ms | 500 ms |
Median site's p75 values from the Chrome UX Report, Sep 2026. Lower is better; green meets Google's "good" threshold. This describes the sites that use each technology, not the technology's own overhead.
Sites that switched
Domains that dropped one technology and adopted the other within about a year, data nobody else gives away free.
Klaviyo to Customer.io
| Domain | When |
|---|---|
| tradeify.co | Aug 2026 |