Email Hosting Providers

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.

Web Servers

Rack CacheRack Cache

Rack Cache Usage Statistics · Download List of All Websites using Rack Cache

Rack::Cache is a component to enable HTTP caching for Rack-based applications such as Rails.

Operating Systems and Servers