1&1 IONOS email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), 1&1 IONOS is the mailbox provider for 4,558 domains — 0.67% of 675,489 domains with MX records. Over the last 30 days its share grew by 0.01 pp. Its strongest TLD is .com (41.3% of its domains). Detection: primary MX record (lowest preference).
Last updated from the 2026-09-24 DNS snapshot.
What 1&1 IONOS represents in this dataset
1&1 IONOS — Europe's largest hosting brand, bundled mail for SMB.
Directory category: Hosting. The classification comes from primary MX record (lowest preference). 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 1&1 IONOS
Across 116 distinct TLDs its top three are .com (41.3%), .de (23.2%), .co.uk (5.9%) — together 70.4% of the 4,558 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 Mailjet (Sinch) (ESP, 155 domains, 3.4% of them), followed by Brevo (ex-Sendinblue) (1.8%). Its share of domains with MX records moved +0.01 pp in 30 days — inside the daily noise of list rotation. Directly comparable by the same detection rule: Self-Hosted, Google Workspace, Microsoft 365. 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 primary MX record (lowest preference) rule, which is an infrastructure fact, not a commercial relationship.
Commonly used together with 1&1 IONOS
What else the same 4,558 domains use — cross-tabulated from the same daily snapshot (2026-09-24).
| Type | Service | Domains | Share of 1&1 IONOS users |
|---|---|---|---|
| ESP | Mailjet (Sinch) | 155 | 3.4% |
| ESP | Brevo (ex-Sendinblue) | 82 | 1.8% |
| ESP | Mailgun | 75 | 1.6% |
| ESP | Amazon SES | 59 | 1.3% |
| ESP | Mandrill | 45 | 1.0% |
| ESP | Mailchimp | 43 | 0.9% |
| ESP | Zendesk | 42 | 0.9% |
| ESP | MailerLite | 39 | 0.9% |
| ESP | Constant Contact | 37 | 0.8% |
| ESP | SendGrid (Twilio) | 37 | 0.8% |
TLD distribution (top 30 of 116)
Frequently asked questions
How many domains use 1&1 IONOS?
4,558 domains in the Tranco top-1M use 1&1 IONOS as their mailbox provider as of September 24, 2026, according to Live Direct Marketing's daily DNS scan.
What is 1&1 IONOS's market share?
1&1 IONOS holds 0.67% of domains with MX records in the Tranco top-1M (snapshot of 2026-09-24). The number is recomputed every day.
Is 1&1 IONOS growing or declining?
1&1 IONOS's share grew by 0.01 percentage points over the last 30 days (as of September 24, 2026).
What are the biggest alternatives to 1&1 IONOS?
The largest mailbox providers in the same category by Tranco top-1M share are: Self-Hosted, Google Workspace, Microsoft 365, Unknown / Other, Generic / unmatched (mx*.*) (as of 2026-09-24).
Largest mailbox providers in this category
Self-Hosted (22.56%) · Google Workspace (21.58%) · Microsoft 365 (17.03%) · Unknown / Other (6.68%) · Generic / unmatched (mx*.*) (2.53%) · Generic / unmatched (mail.*) (1.93%) · Proofpoint (1.86%) · Cloudflare Email Routing (1.76%) · Yandex 360 (1.67%) · Mimecast (1.47%)
Domain sample (top 100 by Tranco rank)
Showing 100 of 4,558 domains.