According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Turbo-SMTP is the email service provider (ESP) for 971 domains — 0.16% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Turbo-SMTP is an email service provider offering mail relay and sending services. It appears predominantly in the SPF records of smaller websites across international TLDs, and frequently co-exists with Microsoft 365 configurations.
Recipients will encounter Turbo-SMTP as sending infrastructure for smaller organisations across international markets, so should account for varied sender reputation profiles. Senders on Turbo-SMTP rely on individual authentication and list discipline, as reputation is distributed across the platform's diverse customer base.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 2 | 0.2% |
| Top 100,000 | 97 | 10.0% |
| Top 1,000,000 | 738 | 76.0% |
| Unranked | 134 | 13.8% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 320 | 33.0% | |
| .it | 297 | 30.6% | |
| .org | 36 | 3.7% | |
| .net | 35 | 3.6% | |
| .de | 32 | 3.3% | |
| .fr | 27 | 2.8% | |
| .nl | 13 | 1.3% | |
| .co.uk | 12 | 1.2% | |
| .be | 10 | 1.0% | |
| .es | 8 | 0.8% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 971 domains.
| Type | Service | Domains | Share of Turbo-SMTP users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 291 | 30.0% |
| Mailbox | Self-Hosted | 207 | 21.3% |
| Mailbox | Google Workspace | 191 | 19.7% |
| Mailbox | Unknown / Other | 88 | 9.1% |
| Mailbox | Generic / unmatched (mx*.*) | 26 | 2.7% |
| Mailbox | OVH Mail | 13 | 1.3% |
| ESP | Amazon SES | 77 | 7.9% |
| ESP | MailUp | 68 | 7.0% |
| ESP | Zendesk | 54 | 5.6% |
| ESP | Mailjet (Sinch) | 52 | 5.4% |
Turbo-SMTP appears predominantly in SPF records of smaller domains across international TLDs, meaning recipients encounter it as legitimate sending infrastructure for non-enterprise organisations. As a shared relay platform, individual sender reputation depends on each sender's own authentication and list quality; recipients should account for the fact that sender reputation is not uniform across Turbo-SMTP's customer base but varies by individual sender practices.
See the full Turbo-SMTP data page (KPI cards, trend, sample domains) →
Turbo-SMTP is a mail relay service deployed predominantly by smaller organisations, often alongside Microsoft 365. It is worth testing if your recipient base spans long-tail or international segments; as a non-mainstream provider, it should not be your sole test platform.
971 domains in the Tranco top-1M use Turbo-SMTP as their email service provider (ESP) as of July 13, 2026 (0.16% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Turbo-SMTP accounts for 0.16% of SPF-publishing domains in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Turbo-SMTP's largest TLD is .com (33.0% of its domains); it appears across 89 TLDs in total.