CloudFlare is a CDN (content delivery network) with a security layer. Once a website is part of the CloudFlare community, its web traffic is routed through CloudFlares global network.
CloudFlares network stores copy of static files closer to web visitors, which means they are delivered more quickly than before. CloudFlare caches resources such as CSS, JavaScript and images. CloudFlares technology automatically decides which resources to cache based on file extension names so there is zero-configuration. CloudFlare also does compression for every request.
CloudFlares network also blocks threats and limits abusive bots before they hit the server, which means less wasted bandwidth and server resources.
