Retarus (DE gateway) email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), Retarus (DE gateway) is the email service provider (ESP) for 190 domains — 0.03% of 637,420 SPF-publishing domains. Its strongest TLD is .de (38.4% of its domains). Detection: include: mechanisms in the SPF record.
Last updated from the 2026-09-24 DNS snapshot.
What Retarus (DE gateway) represents in this dataset
Munich enterprise messaging gateway (transactional + secure email).
Directory category: Gateway. The classification comes from include: mechanisms in the SPF record. It describes observed DNS infrastructure, not a commercial relationship and not the placement of any individual message.
What the 2026-09-24 snapshot shows about Retarus (DE gateway)
Across 26 distinct TLDs its top three are .de (38.4%), .com (31.1%), .fr (5.3%) — together 74.7% of the 190 domains, which makes the footprint narrow — three TLDs cover most of it, which is typical of a regional or single-market operator. The service most often observed on the same domains is Retarus (Mailbox, 88 domains, 46.3% of them), followed by Microsoft 365 (34.2%). Directly comparable by the same detection rule: Amazon SES, SendGrid (Twilio), Mailgun. Ranking between them reflects what is published in DNS, not delivery quality or volume sent. All figures come from a single daily DNS snapshot (2026-09-24); a domain appears here when its published records match the include: mechanisms in the SPF record rule, which is an infrastructure fact, not a commercial relationship.
Commonly used together with Retarus (DE gateway)
What else the same 190 domains use — cross-tabulated from the same daily snapshot (2026-09-24).
| Type | Service | Domains | Share of Retarus (DE gateway) users |
|---|---|---|---|
| Mailbox | Retarus | 88 | 46.3% |
| Mailbox | Microsoft 365 | 65 | 34.2% |
| Mailbox | Self-Hosted | 11 | 5.8% |
| Mailbox | Proofpoint | 6 | 3.2% |
| Mailbox | Unknown / Other | 4 | 2.1% |
| Mailbox | Generic / unmatched (mx*.*) | 4 | 2.1% |
| ESP | IP Made (CDP) | 30 | 15.8% |
| ESP | Mailgun | 19 | 10.0% |
| ESP | Salesforce | 13 | 6.8% |
| ESP | Mailchimp | 12 | 6.3% |
TLD distribution (top 26 of 26)
Frequently asked questions
How many domains use Retarus (DE gateway)?
190 domains in the Tranco top-1M use Retarus (DE gateway) as their email service provider (ESP) as of September 24, 2026, according to Live Direct Marketing's daily DNS scan.
What is Retarus (DE gateway)'s market share?
Retarus (DE gateway) holds 0.03% of SPF-publishing domains in the Tranco top-1M (snapshot of 2026-09-24). The number is recomputed every day.
What are the biggest alternatives to Retarus (DE gateway)?
The largest email service provider (ESP)s in the same category by Tranco top-1M share are: Amazon SES, SendGrid (Twilio), Mailgun, Zendesk, Mailchimp (as of 2026-09-24).
Largest email service provider (ESP)s in this category
Amazon SES (6.23%) · SendGrid (Twilio) (4.68%) · Mailgun (4.01%) · Zendesk (3.77%) · Mailchimp (3.61%) · Mandrill (3.26%) · HubSpot (3.18%) · Salesforce (2.57%) · Mailjet (Sinch) (2.14%) · Cloudflare Email Routing (1.96%)
Domain sample (top 100 by Tranco rank)
Showing 100 of 190 domains.