SMTP.BZ email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 12, 2026), SMTP.BZ is the email service provider (ESP) for 756 domains — 0.12% of 629,828 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 756 domains in the Tranco top-1M use SMTP.BZ (0.12% of SPF-publishing domains).
- Snapshot date: 2026-09-12 — recomputed every day.
- Strongest TLD: .ru (56.1% of its domains).
- Most co-used service: Yandex 360.
- Directory category: email service provider.
Why SMTP.BZ appears in this category
Low-cost transactional SMTP relay.
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.
SMTP.BZ is a Russian email service provider that offers SMTP relay and email infrastructure services, predominantly serving smaller organisations and businesses within Russian-speaking markets. The service is commonly found in SPF include mechanisms across the web, indicating its widespread use for outbound mail authorisation.
Its footprint is distinctly regional—concentrated in the .ru namespace and rarely seen among the world's largest brands, instead serving smaller and regionally focused sites. For senders, this reflects a deliberate choice of infrastructure tailored to regional compliance and local ISP relationships; for receivers, mail authorised via SMTP.BZ typically indicates a smaller or region-focused operation rather than a multinational enterprise.
Where SMTP.BZ sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 2 | 0.3% |
| Top 10,000 | 8 | 1.1% |
| Top 100,000 | 96 | 12.7% |
| Top 1,000,000 | 644 | 85.2% |
| Unranked | 6 | 0.8% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .ru | 424 | 56.1% | |
| .com | 111 | 14.7% | |
| .net | 29 | 3.8% | |
| .online | 19 | 2.5% | |
| .pro | 18 | 2.4% | |
| .su | 17 | 2.2% | |
| .io | 11 | 1.5% | |
| .org | 10 | 1.3% | |
| .by | 9 | 1.2% | |
| .cc | 8 | 1.1% |
What SMTP.BZ users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 756 domains.
| Type | Service | Domains | Share of SMTP.BZ users |
|---|---|---|---|
| Mailbox | Yandex 360 | 242 | 32.0% |
| Mailbox | Self-Hosted | 132 | 17.5% |
| Mailbox | Mail.ru for Business | 102 | 13.5% |
| Mailbox | Google Workspace | 67 | 8.9% |
| Mailbox | Unknown / Other | 20 | 2.6% |
| Mailbox | Timeweb (RU) | 18 | 2.4% |
| ESP | Unisender (RU) | 115 | 15.2% |
| ESP | SendPulse | 68 | 9.0% |
| ESP | Mindbox | 24 | 3.2% |
| ESP | Amazon SES | 23 | 3.0% |
Regional infrastructure patterns and authentication
SMTP.BZ's presence in Russian-speaking markets, particularly its frequent pairing with Yandex 360 in SPF records, reveals how smaller regional organisations often layer email providers to match local compliance and ISP realities. This co-occurrence in authentication records suggests SMTP.BZ typically handles specialist roles—transactional mail, operational alerts, or compliance-driven correspondence—rather than primary marketing channels. Recipients should interpret SMTP.BZ in SPF records as a signal of regional infrastructure choice, not as a reputation indicator.
See the full SMTP.BZ data page (KPI cards, trend, sample domains) →
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Frequently asked questions
What is SMTP.BZ and why does it appear in my SPF record?
SMTP.BZ is a Russian email service provider used by smaller organisations across Russian-speaking markets for outbound mail delivery. Its inclusion in an SPF record means that domain authorises SMTP.BZ's mail servers to send on its behalf, often for transactional or operational correspondence.
How many domains use SMTP.BZ?
756 domains in the Tranco top-1M use SMTP.BZ as their email service provider (ESP) as of September 12, 2026 (0.12% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is SMTP.BZ common enough to affect email deliverability testing?
SMTP.BZ accounts for 0.12% 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 SMTP.BZ most?
SMTP.BZ's largest TLD is .ru (56.1% of its domains); it appears across 60 TLDs in total.