Mimecast email provider statistics and deliverability context
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According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), Mimecast is the email service provider (ESP) for 8,692 domains — 1.36% of 637,420 SPF-publishing domains. Its share has been stable over the last 30 days. Its strongest TLD is .com (58.8% of its domains). Detection: include: mechanisms in the SPF record.
Last updated from the 2026-09-24 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 2026-09-24 snapshot shows about Mimecast
Across 176 distinct TLDs its top three are .com (58.8%), .org (8.6%), .co.uk (6.2%) — together 73.6% of the 8,692 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, 7,167 domains, 82.5% of them), followed by Microsoft 365 (9.6%). 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 (2026-09-24); 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 Mimecast
What else the same 8,692 domains use — cross-tabulated from the same daily snapshot (2026-09-24).
| Type | Service | Domains | Share of Mimecast users |
|---|---|---|---|
| Mailbox | Mimecast | 7,167 | 82.5% |
| Mailbox | Microsoft 365 | 834 | 9.6% |
| Mailbox | Proofpoint | 191 | 2.2% |
| Mailbox | Google Workspace | 167 | 1.9% |
| Mailbox | Unknown / Other | 56 | 0.6% |
| Mailbox | Self-Hosted | 32 | 0.4% |
| ESP | Salesforce | 1,301 | 15.0% |
| ESP | SendGrid (Twilio) | 1,158 | 13.3% |
| ESP | Amazon SES | 1,096 | 12.6% |
| ESP | HubSpot | 893 | 10.3% |
TLD distribution (top 30 of 176)
Frequently asked questions
How many domains use Mimecast?
8,692 domains in the Tranco top-1M use Mimecast as their email service provider (ESP) as of September 24, 2026, according to Live Direct Marketing's daily DNS scan.
What is Mimecast's market share?
Mimecast holds 1.36% of SPF-publishing domains in the Tranco top-1M (snapshot of 2026-09-24). The number is recomputed every day.
Is Mimecast growing or declining?
Mimecast's share has been stable over the last 30 days (±0.01 pp).
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 2026-09-24).
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 8,692 domains.