Mailgun vs SmtpJS
Head-to-head usage across the sites we track.
Top sites by authority
Mailgun · SmtpJS · how many of each technology's sites sit in the web's highest authority tiers
Open Page Rank 9+
33
4
Open Page Rank 8+
594
6
Open Page Rank 7+
2,378
7
Open Page Rank 6+
5,008
7
Open Page Rank 5+
9,287
8
Open Page Rank scores 0 to 10 from the open web link graph; 9+ covers only a few hundred domains worldwide.
By country
Mailgun · SmtpJS · share of sites in each country using one or the other
United States
79,971
86
United Kingdom
32,456
46
Canada
25,014
34
India
24,437
262
Germany
18,963
39
Australia
18,461
29
France
17,380
41
Netherlands
16,595
26
Audience countries from the Chrome UX Report, top markets of either technology.
Real user performance
| Metric | Mailgun | SmtpJS |
|---|---|---|
| LCP | 1.8 s | 2.4 s |
| INP | 75 ms | 75 ms |
| CLS | 0 | 0 |
| TTFB | 700 ms | 800 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.