SMTP2GO email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 14, 2026), SMTP2GO is the email service provider (ESP) for 1,222 domains — 0.19% of 637,677 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 1,222 domains in the Tranco top-1M use SMTP2GO (0.19% of SPF-publishing domains).
- Snapshot date: 2026-09-14 — recomputed every day.
- Strongest TLD: .com (50.2% of its domains).
- Most co-used service: Microsoft 365.
- Directory category: email service provider.
Why SMTP2GO appears in this category
New Zealand transactional email service.
We classify it as a email service provider from include: mechanisms in the SPF record matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
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.
Where SMTP2GO sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 7 | 0.6% |
| Top 100,000 | 98 | 8.0% |
| Top 1,000,000 | 1,109 | 90.8% |
| Unranked | 8 | 0.7% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 613 | 50.2% | |
| .org | 73 | 6.0% | |
| .co.uk | 49 | 4.0% | |
| .net | 46 | 3.8% | |
| .nl | 46 | 3.8% | |
| .com.au | 39 | 3.2% | |
| .it | 25 | 2.0% | |
| .ca | 25 | 2.0% | |
| .com.br | 16 | 1.3% | |
| .no | 16 | 1.3% |
What SMTP2GO users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 1,222 domains.
| Type | Service | Domains | Share of SMTP2GO users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 494 | 40.4% |
| Mailbox | Google Workspace | 199 | 16.3% |
| Mailbox | Self-Hosted | 161 | 13.2% |
| Mailbox | Unknown / Other | 84 | 6.9% |
| Mailbox | Mimecast | 51 | 4.2% |
| Mailbox | Proofpoint | 29 | 2.4% |
| ESP | Mailchimp | 132 | 10.8% |
| ESP | SendGrid (Twilio) | 124 | 10.1% |
| ESP | Amazon SES | 121 | 9.9% |
| ESP | Mandrill | 97 | 7.9% |
Configuration patterns in smaller-site deployments
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) →
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Frequently asked questions
Why does SMTP2GO appear in SPF records alongside Microsoft 365?
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.
How many domains use SMTP2GO?
1,222 domains in the Tranco top-1M use SMTP2GO as their email service provider (ESP) as of September 14, 2026 (0.19% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is SMTP2GO common enough to affect email deliverability testing?
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.
Which countries or TLDs use SMTP2GO most?
SMTP2GO's largest TLD is .com (50.2% of its domains); it appears across 103 TLDs in total.