StackMail email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), StackMail is the email service provider (ESP) for 1,226 domains — 0.19% of 637,420 SPF-publishing domains. Its strongest TLD is .com (46.0% of its domains). Detection: include: mechanisms in the SPF record.
Last updated from the 2026-09-24 DNS snapshot.
What StackMail represents in this dataset
UK shared webmail used by registrars/resellers.
Directory category: Mailbox. 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 StackMail
Across 82 distinct TLDs its top three are .com (46.0%), .co.uk (24.7%), .net (4.1%) — together 74.8% of the 1,226 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 StackMail (UK mailbox) (Mailbox, 1,027 domains, 83.8% of them), followed by Microsoft 365 (6.7%). 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 StackMail
What else the same 1,226 domains use — cross-tabulated from the same daily snapshot (2026-09-24).
| Type | Service | Domains | Share of StackMail users |
|---|---|---|---|
| Mailbox | StackMail (UK mailbox) | 1,027 | 83.8% |
| Mailbox | Microsoft 365 | 82 | 6.7% |
| Mailbox | Google Workspace | 69 | 5.6% |
| Mailbox | Self-Hosted | 15 | 1.2% |
| Mailbox | Unknown / Other | 7 | 0.6% |
| Mailbox | Barracuda | 4 | 0.3% |
| ESP | MailerLite | 20 | 1.6% |
| ESP | Mailchimp | 18 | 1.5% |
| ESP | Mandrill | 18 | 1.5% |
| ESP | Amazon SES | 15 | 1.2% |
TLD distribution (top 30 of 82)
Frequently asked questions
How many domains use StackMail?
1,226 domains in the Tranco top-1M use StackMail as their email service provider (ESP) as of September 24, 2026, according to Live Direct Marketing's daily DNS scan.
What is StackMail's market share?
StackMail holds 0.19% 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 StackMail?
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 1,226 domains.