We read the MX and SPF records of all 100 companies on the Forbes Cloud 100, 2025 edition. 78 of them receive their mail directly on Google Workspace, and only 3 on Microsoft 365. Another 15 put a security gateway in front, most often Proofpoint.
include: terms and names 3 services we recognise.No lookup failed: every number below has all 100 companies in it, with no unknowns.
A domain’s MX records tell other mail servers where to deliver its email. We matched the highest-priority MX hosts, where mail actually goes, against each provider’s known hostnames.
| Primary MX points at | Companies | Share |
|---|---|---|
| Google Workspace | 78 | 78% |
| A secure email gateway | 15 | 15% |
| Microsoft 365 | 3 | 3% |
| Own servers or another host | 4 | 4% |
| No MX record | 0 | 0% |
These companies lean heavily towards Google: 78 to 3 among the ones whose mailbox provider shows in MX. The 4 “own servers or another host” companies point MX at their own mail servers or at a host other than Google, Microsoft or a gateway; for 1 of them, SPF authorises Google Workspace.
A secure email gateway scans inbound mail before passing it on to the real mailbox provider, so MX shows the gateway instead of the mailbox. 15 of 100 use one:
| Gateway in MX | Companies |
|---|---|
| Proofpoint | 10 |
| Mimecast | 3 |
| Cloudflare Email Security | 2 |
To see past the gateway, we read each of these companies’ SPF record and followed its includes, as the email provider checker does. SPF lists who may send as the domain, so this is an inference, not proof of where mailboxes live:
| SPF of the 15 gateway companies authorises | Companies |
|---|---|
| Google Workspace (likely mailbox provider) | 8 |
| Microsoft 365 | 0 |
| Neither | 7 |
Counting those 8 inferred ones, Google Workspace is the likely mailbox provider for 86 of 100. Microsoft 365 stays at 3. For the 7 “neither” companies, DNS doesn’t show the mailbox provider: they may send through the gateway itself or through a service SPF doesn’t name.
All 100 publish exactly one SPF record. Each include: in it authorises a service to send mail as the company’s domain: a marketing platform, a help desk, a transactional email API. We matched every include: and redirect= target against our list of known senders, and followed each one we didn’t recognise one level down (a company’s own _spf.example.com often includes the services). A company counts once per service.
| Service authorised in SPF | Companies |
|---|---|
| Google Workspace | 67 |
| Salesforce (incl. Pardot) | 36 |
| Zendesk | 28 |
| Amazon SES | 27 |
| Marketo | 26 |
| HubSpot | 25 |
| Mailchimp / Mandrill | 14 |
| SendGrid | 11 |
| Mailgun | 9 |
| Greenhouse | 8 |
| Microsoft 365 | 6 |
| Proofpoint | 6 |
Next come Qualtrics (5), Atlassian (4), Postmark (3), Mailjet (3), Brevo (2) and Help Scout (2). Two other names appear often in these records: docebosaas.com, Docebo’s learning platform (9), and stspg-customer.com, Atlassian Statuspage notifications (7). Among email APIs for product mail, Amazon SES (27) leads SendGrid (11) and Mailgun (9).
include: terms (from 0 to 9), and the median company authorises 3 services we recognise.To see which provider a list of companies uses, the free email provider checker runs the same MX lookup for up to 50 domains in your browser, with the SPF note for gateways. For larger lists, Tech Enricher returns each domain’s email provider and the sending services in its SPF (spfSenders), next to its CMS, analytics and the rest of its website stack. $0.02 per domain report, charged only for a domain whose homepage we can fetch and where we detect at least one technology, email provider, DNS provider or SPF sender.
More from the same 100 companies: DMARC adoption across the Forbes Cloud 100 (SPF, DMARC policy, MTA-STS and BIMI) and which ATS these companies hire through.