Send-Box email service provider (ESP)
According to Live Direct Marketing's daily Tranco top-1M scan (September 12, 2026), Send-Box is the email service provider (ESP) for 115 domains — 0.02% of 629,828 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
Key facts
- 115 domains in the Tranco top-1M use Send-Box (0.02% of SPF-publishing domains).
- Snapshot date: 2026-09-12 — recomputed every day.
- Strongest TLD: .ru (75.7% of its domains).
- Most co-used service: Mail.ru for Business.
- Directory category: email service provider.
Why Send-Box appears in this category
Send-Box — Russian email marketing platform.
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.
Send-Box is a Russian-focused email service provider that operates primarily in the .ru market, serving smaller organisations and regional deployments. It is most commonly encountered as part of email infrastructure in Russian and Eastern European markets, often appearing alongside Mail.ru for Business within the broader regional email ecosystem.
For senders and mail infrastructure operators, Send-Box's concentrated footprint in regional markets means it rarely poses the high-volume sender reputation challenges of mainstream global providers. However, when targeting or receiving mail involving Russian or Eastern European users, understanding Send-Box's presence in SPF records and routing paths becomes relevant to sender authentication validation and infrastructure planning.
Where Send-Box sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 1 | 0.9% |
| Top 100,000 | 22 | 19.1% |
| Top 1,000,000 | 89 | 77.4% |
| Unranked | 3 | 2.6% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .ru | 87 | 75.7% | |
| .com | 7 | 6.1% | |
| .kz | 6 | 5.2% | |
| .site | 1 | 0.9% | |
| .su | 1 | 0.9% | |
| .by | 1 | 0.9% | |
| .ai | 1 | 0.9% | |
| .online | 1 | 0.9% | |
| .toys | 1 | 0.9% | |
| .team | 1 | 0.9% |
What Send-Box users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 115 domains.
| Type | Service | Domains | Share of Send-Box users |
|---|---|---|---|
| Mailbox | Mail.ru for Business | 42 | 36.5% |
| Mailbox | Yandex 360 | 25 | 21.7% |
| Mailbox | Self-Hosted | 25 | 21.7% |
| Mailbox | Google Workspace | 7 | 6.1% |
| Mailbox | Unknown / Other | 4 | 3.5% |
| Mailbox | Generic / unmatched (mx*.*) | 3 | 2.6% |
| ESP | Unisender (RU) | 41 | 35.7% |
| ESP | DashaMail (RU) | 13 | 11.3% |
| ESP | SendPulse | 12 | 10.4% |
| ESP | SMTP.BZ | 12 | 10.4% |
SPF Include Chains and Authentication Path Complexity
Send-Box appears in detection datasets primarily through SPF include mechanisms, indicating it serves as a delegated mail routing component for its users. When an organisation includes Send-Box in their SPF record alongside other regional providers, each include requires DNS lookups during mail server authentication checks. This multi-provider stacking, particularly common in Eastern European deployments, means DMARC and SPF validators must account for multiple possible sender pathways and handle authentication results from several routing layers.
See the full Send-Box data page (KPI cards, trend, sample domains) →
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Frequently asked questions
What is Send-Box and why does it appear in SPF records?
Send-Box is a Russian-focused email service provider that appears as an SPF include for regional organisations. It is primarily concentrated in smaller-scale deployments in the .ru market rather than global enterprise infrastructure.
How many domains use Send-Box?
115 domains in the Tranco top-1M use Send-Box as their email service provider (ESP) as of September 12, 2026 (0.02% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
Is Send-Box common enough to affect email deliverability testing?
Send-Box accounts for 0.02% 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 Send-Box most?
Send-Box's largest TLD is .ru (75.7% of its domains); it appears across 18 TLDs in total.