Postmark email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 13, 2026), Postmark is the email service provider (ESP) for 2,939 domains — 0.47% of 628,913 SPF-publishing domains. Its share has been stable over the last 30 days. Its strongest TLD is .com (56.9% of its domains). Detection: include: mechanisms in the SPF record.
Last updated from the 2026-09-13 DNS snapshot.
What Postmark represents in this dataset
Transactional email service known for high deliverability and developer UX.
Directory category: Esp. 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 2026-09-13 snapshot shows about Postmark
Across 154 distinct TLDs its top three are .com (56.9%), .org (5.1%), .io (3.0%) — together 65.0% of the 2,939 domains, which makes the footprint moderately concentrated, with a recognisable home market. The service most often observed on the same domains is Google Workspace (Mailbox, 1,483 domains, 50.5% of them), followed by Microsoft 365 (21.6%). Its share of SPF-publishing domains has not moved measurably in 30 days. 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 (2026-09-13); 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 Postmark
What else the same 2,939 domains use — cross-tabulated from the same daily snapshot (2026-09-13).
| Type | Service | Domains | Share of Postmark users |
|---|---|---|---|
| Mailbox | Google Workspace | 1,483 | 50.5% |
| Mailbox | Microsoft 365 | 635 | 21.6% |
| Mailbox | Self-Hosted | 144 | 4.9% |
| Mailbox | Generic / unmatched (mx*.*) | 108 | 3.7% |
| Mailbox | Unknown / Other | 83 | 2.8% |
| Mailbox | Mimecast | 66 | 2.2% |
| ESP | Mailchimp | 413 | 14.1% |
| ESP | Zendesk | 389 | 13.2% |
| ESP | SendGrid (Twilio) | 380 | 12.9% |
| ESP | Amazon SES | 379 | 12.9% |
TLD distribution (top 30 of 154)
Frequently asked questions
How many domains use Postmark?
2,939 domains in the Tranco top-1M use Postmark as their email service provider (ESP) as of September 13, 2026, according to Live Direct Marketing's daily DNS scan.
What is Postmark's market share?
Postmark holds 0.47% of SPF-publishing domains in the Tranco top-1M (snapshot of 2026-09-13). The number is recomputed every day.
Is Postmark growing or declining?
Postmark's share has been stable over the last 30 days (±0.01 pp).
What are the biggest alternatives to Postmark?
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 2026-09-13).
Largest email service provider (ESP)s in this category
Amazon SES (6.19%) · SendGrid (Twilio) (4.64%) · Mailgun (4.01%) · Zendesk (3.77%) · Mailchimp (3.57%) · Mandrill (3.25%) · HubSpot (3.12%) · Salesforce (2.55%) · Mailjet (Sinch) (2.12%) · Cloudflare Email Routing (1.95%)
Domain sample (top 100 by Tranco rank)
Showing 100 of 2,939 domains.