According to Live Direct Marketing's daily Tranco top-1M scan (July 12, 2026), StackMail (UK mailbox) is the mailbox provider for 1,078 domains — 0.16% of 658,108 domains with MX records. Detection method: primary MX record (lowest preference).
StackMail (UK mailbox) is a mailbox hosting provider that supplies email infrastructure to small and mid-market websites. It operates as a managed email service, handling inbound and outbound mail for sites that choose not to run their own mail stack.
StackMail's presence across the Tranco top-1M list is concentrated in smaller domains and the .com namespace, with a global but US-skewed distribution. This pattern means senders and operators encounter StackMail most often in long-tail sites rather than the largest brands, making it a relevant secondary consideration for email programmes targeting broad or SMB-focused audiences.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 25 | 2.3% |
| Top 1,000,000 | 573 | 53.2% |
| Unranked | 480 | 44.5% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 572 | 53.1% | |
| .co.uk | 159 | 14.7% | |
| .org | 51 | 4.7% | |
| .net | 49 | 4.5% | |
| .uk | 37 | 3.4% | |
| .site | 20 | 1.9% | |
| .org.uk | 16 | 1.5% | |
| .ma | 9 | 0.8% | |
| .pk | 8 | 0.7% | |
| .info | 8 | 0.7% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 1,078 domains.
| Type | Service | Domains | Share of StackMail (UK mailbox) users |
|---|---|---|---|
| ESP | StackMail | 923 | 85.6% |
| ESP | MailerSend | 14 | 1.3% |
| ESP | Mailchimp | 7 | 0.6% |
| ESP | Mailjet (Sinch) | 5 | 0.5% |
| ESP | Zoho ZeptoMail | 3 | 0.3% |
| ESP | HubSpot | 3 | 0.3% |
| ESP | Amazon SES | 3 | 0.3% |
| ESP | Elastic Email | 3 | 0.3% |
| ESP | Mandrill | 3 | 0.3% |
| ESP | Emsd1 (transactional) | 2 | 0.2% |
StackMail occupies a niche as a mailbox provider for smaller sites and SMBs, which means bounce handling, authentication strictness, and filtering posture can vary across StackMail-hosted domains depending on individual site configuration. This variation makes StackMail an important checkpoint for senders targeting broad, long-tail, or SMB audiences rather than enterprise domains only.
See the full StackMail (UK mailbox) data page (KPI cards, trend, sample domains) →
StackMail is a mailbox hosting provider used primarily by smaller sites and SMBs across .com domains. Testing against StackMail is relevant if your recipient list includes long-tail or SMB addresses; otherwise, it is a secondary consideration.
1,078 domains in the Tranco top-1M use StackMail (UK mailbox) as their mailbox provider as of July 12, 2026 (0.16% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
StackMail (UK mailbox) accounts for 0.16% 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.
StackMail (UK mailbox)'s largest TLD is .com (53.1% of its domains); it appears across 96 TLDs in total.