One.com (DK) mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 14, 2026), One.com (DK) is the mailbox provider for 43 domains — 0.01% of 674,487 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 43 domains in the Tranco top-1M use One.com (DK) (0.01% of domains with MX records).
- Snapshot date: 2026-09-14 — recomputed every day.
- Strongest TLD: .com (37.2% of its domains).
- Region skew: Global / US-skewed.
- Most co-used service: SendGrid (Twilio).
- Directory category: hosting mail bundle.
Why One.com (DK) appears in this category
Danish/European registrar+hosting (Group.ONE) with bundled mail.
We classify it as a hosting mail bundle from primary MX record (lowest preference) matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
One.com is a mailbox provider serving as the primary mail host for many smaller organisations and individual domain owners rather than large enterprises. Its customer base sits in the long tail of smaller sites rather than the largest brands, making it a provider primarily for SMEs and individuals managing their own domain registrations and hosting.
One.com's footprint in email infrastructure is characterised by international spread across many top-level domains, with .com registrations predominant. The user base skews global with a US emphasis. A notable pattern shows One.com domains frequently paired with Mailgun for outbound mail delivery, suggesting many organisations host inbound mail on One.com whilst delegating sending to Mailgun. This split-stack approach and the distributed nature of One.com's customer base make it a relevant inclusion in real-world deliverability testing and authentication planning.
Where One.com (DK) sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 2 | 4.7% |
| Top 1,000,000 | 41 | 95.3% |
| Unranked | 0 | 0.0% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 16 | 37.2% | |
| .se | 5 | 11.6% | |
| .dk | 4 | 9.3% | |
| .co.uk | 4 | 9.3% | |
| .uk | 2 | 4.7% | |
| .org | 1 | 2.3% | |
| .ch | 1 | 2.3% | |
| .eu | 1 | 2.3% | |
| .it | 1 | 2.3% | |
| .fr | 1 | 2.3% |
What One.com (DK) users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 43 domains.
| Type | Service | Domains | Share of One.com (DK) users |
|---|---|---|---|
| ESP | SendGrid (Twilio) | 3 | 7.0% |
| ESP | Mailgun | 2 | 4.7% |
| ESP | Brevo (ex-Sendinblue) | 2 | 4.7% |
| ESP | MailerLite | 2 | 4.7% |
| ESP | Elastic Email | 2 | 4.7% |
| ESP | Mailendo | 2 | 4.7% |
| ESP | Cloudflare Email Routing | 1 | 2.3% |
| ESP | Mailjet (Sinch) | 1 | 2.3% |
One.com and Mailgun: SPF Configuration for Split-Stack Mail
The common pairing of One.com inbound hosting with Mailgun outbound sending creates a specific authentication scenario. Organisations that send mail via Mailgun on behalf of domains hosted on One.com must configure SPF records to authorise both One.com's mail servers and Mailgun's sending infrastructure, or face authentication-based rejection. This infrastructure choice is common enough across One.com's customer base that understanding it is valuable for anyone testing deliverability against the long tail of smaller, distributed domain portfolios.
See the full One.com (DK) data page (KPI cards, trend, sample domains) →
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Frequently asked questions
Is One.com worth testing for email deliverability?
Yes, if your recipients include small businesses and individuals on shared hosting. One.com's distribution across the long tail of smaller domains and the prevalence of Mailgun pairing means real-world senders will encounter this infrastructure frequently enough to warrant testing.
How many domains use One.com (DK)?
43 domains in the Tranco top-1M use One.com (DK) as their mailbox provider as of September 14, 2026 (0.01% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is One.com (DK) common enough to affect email deliverability testing?
One.com (DK) accounts for 0.01% of domains with MX records 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 One.com (DK) most?
One.com (DK)'s largest TLD is .com (37.2% of its domains); it appears across 17 TLDs in total.