Email Hosting Providers

MailgunMailgun

Mailgun Usage Statistics · Download List of All Websites using Mailgun

Mailgun is a set of APIs that allow you to send, receive, track and store email effortlessly.

Transactional Email

MandrillMandrill

Mandrill Usage Statistics · Download List of All Websites using Mandrill

Mandrill is an email infrastructure service. Detailed analytics offer insight to measure email performance.

Transactional Email

Google Apps for BusinessGoogle Apps for Business

Google Apps for Business Usage Statistics · Download List of All Websites using Google Apps for Business

Web-based email, calendar, and documents for teams. Renamed to Google Apps for Work, but now known as G Suite From Google Cloud.

Business Email Hosting

SPFSPF

SPF Usage Statistics · Download List of All Websites using SPF

The Sender Policy Framework is an open standard specifying a technical method to prevent sender address forgery.

Operating Systems and Servers