> For the complete documentation index, see [llms.txt](https://appseed.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://appseed.gitbook.io/docs/content/what-is/wsgi.md).

# What IS WSGI

Short introduction to WSGI interface implemented by well-known libraries like Flask and Django.

**WSGI** is the Web Server Gateway Interface. It is a specification that describes how a web server communicates with web applications, and how web applications can be chained together to process one request. WSGI is a Python standard described in detail in [PEP 3333](https://www.python.org/dev/peps/pep-3333/).

### What is WSGI

In a single sentence, *WSGI is just an interface specification by which the server and application communicate.* This interface used by many popular frameworks like Flas and Django is defined in the [PEP 3333](https://www.python.org/dev/peps/pep-3333) specification for both parties: server and WSGI application.

Python 2.5 and later comes with a WSGI server which will be used in this tutorial. In 2.4 and earlier it can be installed.

### WSGI Frameworks

A short-list with web frameworks with native WSGI support:

* [Flask](https://flask.palletsprojects.com/en/1.1.x/) - Flask is a microframework for Python based on Werkzeug, Jinja 2 and good intentions
* [Django](https://www.djangoproject.com/) - The web framework for perfectionists with deadlines.
* [Pyramid](http://www.pylonsproject.org/projects/pyramid/about) - Pyramid is a minimalist web framework aiming at composability and making developers paying only for what they use.
* [Falcon](http://www.pylonsproject.org/projects/pyramid/about) - Falcon is a high-performance Python framework for building cloud APIs

### WSGI Resources

* [WSGI](https://wsgi.readthedocs.io/en/latest/) - official documentation
* [An introduction to WSGI](http://ivory.idyll.org/articles/wsgi-intro/what-is-wsgi.html) by Titus Brown
* [Frameworks that run on WSGI](https://wsgi.readthedocs.io/en/latest/frameworks.html) - a curated list