The Static File Servers

Most websites have resources they deliver to browsers that do not change during the regular operation of the site. The images and CSS files that describe the appearance of the site, the JavaScript code that runs in the browser, and HTML files for pages without dynamic components are examples of these resources, collectively known as static files. Since the delivery of these files doesn’t involve application code, it’s unnecessary and inefficient to serve them from the application servers.

Instead, App Engine provides a separate set of servers dedicated to delivering static files. These servers are optimized for both internal architecture and network topology to handle requests for static resources. To the client, static files look like any other resource served by your app.