Email Hosting Providers

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.

Standard

AuthSMTPAuthSMTP

AuthSMTP Usage Statistics · Download List of All Websites using AuthSMTP

AuthSMTP is an authenticated SMTP mail service designed to solve most of the problems experienced when sending mail from your email program, application, server, cell phone or mobile device.

Web Hosting Providers

StratoStrato

Strato Usage Statistics · Download List of All Websites using Strato

German based hosting solution owned by Deutsche Telekom.

German hosting

Web Servers

ApacheApache

Apache Usage Statistics · Download List of All Websites using Apache

Apache has been the most popular web server on the Internet since April 1996.

Operating Systems and Servers