According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), SMTP2GO is the email service provider (ESP) for 1,191 domains — 0.19% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
SMTP2GO is a transactional email service provider that handles SMTP relay and mail routing for applications and web services. It routes outbound delivery for order confirmations, password resets, and system notifications.
Its presence in SPF records across the Tranco list—predominantly in the .com namespace and among mid-market and smaller organisations—often occurs alongside Microsoft 365, indicating a common deployment pattern. For administrators evaluating inbound mail sources, SMTP2GO traffic is typically low-volume, transactional, and legitimate, originating from application integrations rather than marketing infrastructure.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 8 | 0.7% |
| Top 100,000 | 97 | 8.1% |
| Top 1,000,000 | 921 | 77.3% |
| Unranked | 165 | 13.9% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 587 | 49.3% | |
| .org | 84 | 7.1% | |
| .co.uk | 48 | 4.0% | |
| .net | 46 | 3.9% | |
| .com.au | 44 | 3.7% | |
| .nl | 39 | 3.3% | |
| .ca | 28 | 2.4% | |
| .it | 19 | 1.6% | |
| .de | 14 | 1.2% | |
| .no | 14 | 1.2% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 1,191 domains.
| Type | Service | Domains | Share of SMTP2GO users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 473 | 39.7% |
| Mailbox | Google Workspace | 185 | 15.5% |
| Mailbox | Self-Hosted | 152 | 12.8% |
| Mailbox | Unknown / Other | 95 | 8.0% |
| Mailbox | Mimecast | 49 | 4.1% |
| Mailbox | Proofpoint | 32 | 2.7% |
| ESP | Mailchimp | 135 | 11.3% |
| ESP | SendGrid (Twilio) | 125 | 10.5% |
| ESP | Amazon SES | 124 | 10.4% |
| ESP | Mandrill | 100 | 8.4% |
SMTP2GO's prevalence in the long tail of the Tranco list, combined with its frequent pairing with Microsoft 365, reflects a common mid-market deployment: organisations using Office 365 for primary email whilst delegating transactional mail—receipts, alerts, system notifications—to a dedicated relay service. This separation can improve deliverability by isolating transactional reputation from user-facing mail, though it requires careful SPF configuration to prevent conflicts between the two providers.
See the full SMTP2GO data page (KPI cards, trend, sample domains) →
SMTP2GO is a transactional email relay service commonly used by organisations to route order confirmations, alerts, and system notifications separately from their primary mail infrastructure. When paired with Microsoft 365, it indicates that a company is delegating application mail to a dedicated provider to avoid reputation bleed between transactional and user-facing mail.
1,191 domains in the Tranco top-1M use SMTP2GO as their email service provider (ESP) as of July 13, 2026 (0.19% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
SMTP2GO accounts for 0.19% 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.
SMTP2GO's largest TLD is .com (49.3% of its domains); it appears across 101 TLDs in total.