123-reg (UK) mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 17, 2026), 123-reg (UK) is the mailbox provider for 195 domains — 0.03% of 673,136 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 195 domains in the Tranco top-1M use 123-reg (UK) (0.03% of domains with MX records).
- Snapshot date: 2026-09-17 — recomputed every day.
- Strongest TLD: .co.uk (40.0% of its domains).
- Region skew: United Kingdom.
- Most co-used service: SendGrid (Twilio).
- Directory category: hosting mail bundle.
Why 123-reg (UK) appears in this category
UK registrar (GoDaddy group) bundling mailbox with domain registration.
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.
123-reg is a UK-based domain registrar and web hosting provider that operates email infrastructure for its customers' registered domains. It primarily serves small to medium-sized businesses and operates globally, hosting email, domains, and web services for many SMB customers.
In email deliverability terms, 123-reg occupies the long tail of smaller, non-enterprise domains rather than the largest global brands. Its footprint is globally distributed across many top-level domains, with notable presence in the US market. Because 123-reg frequently appears alongside SendGrid in customer infrastructure, senders and filtering systems encounter its mailboxes and authentication requirements regularly when dealing with diverse, SMB-focused recipient bases.
Where 123-reg (UK) 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 | 5 | 2.6% |
| Top 1,000,000 | 183 | 93.8% |
| Unranked | 7 | 3.6% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .co.uk | 78 | 40.0% | |
| .com | 70 | 35.9% | |
| .org | 13 | 6.7% | |
| .org.uk | 11 | 5.6% | |
| .net | 9 | 4.6% | |
| .club | 2 | 1.0% | |
| .co | 2 | 1.0% | |
| .trade | 1 | 0.5% | |
| .cloud | 1 | 0.5% | |
| .us | 1 | 0.5% |
What 123-reg (UK) users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 195 domains.
| Type | Service | Domains | Share of 123-reg (UK) users |
|---|---|---|---|
| ESP | SendGrid (Twilio) | 4 | 2.1% |
| ESP | Amazon SES | 4 | 2.1% |
| ESP | Mandrill | 3 | 1.5% |
| ESP | Campaign Monitor | 2 | 1.0% |
| ESP | Mailgun | 2 | 1.0% |
| ESP | Mailjet (Sinch) | 2 | 1.0% |
| ESP | Zoho Campaigns | 1 | 0.5% |
| ESP | Adestra (MessageFocus) | 1 | 0.5% |
| ESP | Postmark | 1 | 0.5% |
| ESP | Brevo (ex-Sendinblue) | 1 | 0.5% |
SendGrid and split-service email configuration
Many 123-reg domains maintain inbound mail at 123-reg whilst routing outbound campaigns through SendGrid or similar third-party services. This split-service model requires both the primary mailbox provider and the outbound service to be authorised in the domain's SPF record and properly configured for DKIM signing. Misconfigurations in this arrangement—incomplete SPF policies or inconsistent authentication setup—are a common source of deliverability failures among 123-reg customers.
See the full 123-reg (UK) data page (KPI cards, trend, sample domains) →
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Frequently asked questions
Should I test email deliverability to 123-reg mailboxes?
Yes; 123-reg hosts mail for a substantial segment of small-to-medium business domains, making it a representative test target for senders reaching diverse, non-enterprise recipient bases.
How many domains use 123-reg (UK)?
195 domains in the Tranco top-1M use 123-reg (UK) as their mailbox provider as of September 17, 2026 (0.03% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is 123-reg (UK) common enough to affect email deliverability testing?
123-reg (UK) accounts for 0.03% 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 123-reg (UK) most?
123-reg (UK)'s largest TLD is .co.uk (40.0% of its domains); it appears across 17 TLDs in total.