According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), Retarus is the mailbox provider for 116 domains — 0.02% of 658,711 domains with MX records. Detection method: primary MX record (lowest preference).
Retarus is a mailbox provider and email gateway operator based in Germany, offering inbound and outbound email services for organisations across multiple sectors and geographies, with particular strength in German-speaking regions.
Unlike megaproviders such as Microsoft or Google, Retarus predominantly hosts smaller and mid-market organisations rather than the largest global brands. Its European footprint, concentrated in German and neighbouring TLDs, means email practitioners sending to or receiving from Retarus-hosted domains often engage with regionally-diverse business entities. For senders targeting European markets, particularly Germany, Retarus represents a relevant testing point within regional compliance strategies rather than a universal baseline.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 1 | 0.9% |
| Top 100,000 | 25 | 21.6% |
| Top 1,000,000 | 87 | 75.0% |
| Unranked | 3 | 2.6% |
| TLD | Domains | Share | |
|---|---|---|---|
| .de | 47 | 40.5% | |
| .com | 34 | 29.3% | |
| .at | 6 | 5.2% | |
| .fr | 6 | 5.2% | |
| .ch | 4 | 3.4% | |
| .eu | 2 | 1.7% | |
| .nl | 2 | 1.7% | |
| .net | 2 | 1.7% | |
| .it | 1 | 0.9% | |
| .tv | 1 | 0.9% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 116 domains.
| Type | Service | Domains | Share of Retarus users |
|---|---|---|---|
| ESP | Retarus (DE gateway) | 83 | 71.6% |
| ESP | IP Made (CDP) | 20 | 17.2% |
| ESP | Mailjet (Sinch) | 7 | 6.0% |
| ESP | Amazon SES | 7 | 6.0% |
| ESP | Salesforce | 6 | 5.2% |
| ESP | Mandrill | 6 | 5.2% |
| ESP | Salesforce Marketing Cloud | 6 | 5.2% |
| ESP | Zendesk | 4 | 3.4% |
| ESP | SendGrid (Twilio) | 4 | 3.4% |
| ESP | Constant Contact | 4 | 3.4% |
Retarus's concentration in smaller and mid-market European organisations, particularly in Germany and adjacent regions, makes it a relevant testing point for campaigns targeting those markets. However, because it does not represent global megaproviders or consumer segments, it should be tested as a regional priority alongside broader provider coverage rather than treated as a universal compliance baseline.
See the full Retarus data page (KPI cards, trend, sample domains) →
Test against Retarus if targeting German-speaking markets or mid-market European organisations. Because it hosts smaller organisations rather than major consumer segments, it is a regional priority rather than a global compliance requirement.
116 domains in the Tranco top-1M use Retarus as their mailbox provider as of July 13, 2026 (0.02% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Retarus accounts for 0.02% 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.
Retarus's largest TLD is .de (40.5% of its domains); it appears across 21 TLDs in total.