WSGI – the Web Standard Gateway Interface – is a Python standard. It is loosely based on the CGI – common gateway interface – standard, which web servers used to interact with scripts. With higher loads came the need to have a persistent Python process, inside the web server. Originally, each server had its own unique way of running Python applications. That meant each application had to decide on a web server and could not move away. WSGI was designed as a low-level standard for web applications written in Python to interact with web servers that can run Python internally (either by being written in Python themselves, or by embedding the Python interpreter).