One.com (DK) mailbox provider

According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), One.com (DK) is the mailbox provider for 43 domains — 0.01% of 658,711 domains with MX records. Detection method: primary MX record (lowest preference).

Key facts

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 bandDomainsShare of its base
Top 1,00000.0%
Top 10,00000.0%
Top 100,00024.7%
Top 1,000,0002762.8%
Unranked1432.6%

Top-level domain split

TLDDomainsShare
.com1739.5%
.se511.6%
.co.uk511.6%
.dk49.3%
.uk24.7%
.nl24.7%
.de24.7%
.it12.3%
.net12.3%
.no12.3%

What One.com (DK) users also use

Cross-tabulated from the same daily snapshot — the other email services seen on the same 43 domains.

TypeServiceDomainsShare of One.com (DK) users
ESPSendGrid (Twilio)37.0%
ESPMailgun37.0%
ESPMailendo24.7%
ESPMailerSend24.7%
ESPElastic Email24.7%
ESPBrevo (ex-Sendinblue)12.3%
ESPMailjet (Sinch)12.3%
ESPMailchimp12.3%

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 July 13, 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 (39.5% of its domains); it appears across 13 TLDs in total.

Other mailbox providers

Self-Hosted (22.44%)Google Workspace (21.79%)Microsoft 365 (16.74%)Unknown / Other (7.54%)Generic / unmatched (mx*.*) (2.57%)Proofpoint (1.90%)Generic / unmatched (mail.*) (1.75%)Yandex 360 (1.64%)Cloudflare Email Routing (1.60%)Mimecast (1.52%)