Mimecast email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 13, 2026), Mimecast is the email service provider (ESP) for 8,481 domains — 1.35% of 628,913 SPF-publishing domains. Over the last 30 days its share declined by 0.03 pp. Its strongest TLD is .com (58.8% of its domains). Detection: include: mechanisms in the SPF record.
Last updated from the 2026-09-13 DNS snapshot.
What Mimecast represents in this dataset
UK-origin enterprise email security gateway (Permira-owned).
Directory category: Gateway. 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 Mimecast
Across 175 distinct TLDs its top three are .com (58.8%), .org (8.3%), .co.uk (6.2%) — together 73.3% of the 8,481 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 Mimecast (Mailbox, 7,000 domains, 82.5% of them), followed by Microsoft 365 (9.4%). Its share of SPF-publishing domains moved -0.03 pp in 30 days — inside the daily noise of list rotation. 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 Mimecast
What else the same 8,481 domains use — cross-tabulated from the same daily snapshot (2026-09-13).
| Type | Service | Domains | Share of Mimecast users |
|---|---|---|---|
| Mailbox | Mimecast | 7,000 | 82.5% |
| Mailbox | Microsoft 365 | 797 | 9.4% |
| Mailbox | Proofpoint | 198 | 2.3% |
| Mailbox | Google Workspace | 165 | 1.9% |
| Mailbox | Unknown / Other | 58 | 0.7% |
| Mailbox | Self-Hosted | 29 | 0.3% |
| ESP | Salesforce | 1,275 | 15.0% |
| ESP | SendGrid (Twilio) | 1,127 | 13.3% |
| ESP | Amazon SES | 1,078 | 12.7% |
| ESP | HubSpot | 857 | 10.1% |
TLD distribution (top 30 of 175)
Frequently asked questions
How many domains use Mimecast?
8,481 domains in the Tranco top-1M use Mimecast as their email service provider (ESP) as of September 13, 2026, according to Live Direct Marketing's daily DNS scan.
What is Mimecast's market share?
Mimecast holds 1.35% of SPF-publishing domains in the Tranco top-1M (snapshot of 2026-09-13). The number is recomputed every day.
Is Mimecast growing or declining?
Mimecast's share declined by 0.03 percentage points over the last 30 days (as of September 13, 2026).
What are the biggest alternatives to Mimecast?
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 8,481 domains.