It’s been almost 15 years since the last standard of HTTP was ratified. HTTP is the protocol which transports web pages across the internet. It’s a brilliantly thought out and quite simple protocol. It’s beginning to show it’s age though, especially with the rise of many requests across multiple web servers. AJAX and newer technologies like WebSockets have worked around it’s limitations. It’s inefficient at connections, is designed to be stateless, so doesn’t maintain data in it’s headers between requests, and it’s not great at doing lots of requests in parallel.