Web applications typically disseminate information via three server layers: Web server - First layer: Receives request from client(web browser) Application server - 2nd layer: Receives requests from web server if the client is requesting dynamic content Database - 3rd layer: Receives database queries from web framework's request handler methods In this example , nginx is the web server, gunicorn is the application server (interface between nginx and web framwork request handling function) and the database can be assumed to be a lightweight sqlite3 database. Example: Django architecture Alternatives to nginx : Cherokee Apache HTTP server Alternatives for gunicorn: Apache Mongoose
