# Waitress — Flask Documentation (3.1.x)

# Waitress

Waitress is a pure Python WSGI server.

- It is easy to configure.

- It supports Windows directly.

- It is easy to install as it does not require additional dependencies or compilation.

- It does not support streaming requests, full request data is always buffered.

- It uses a single process with multiple thread workers.

This page outlines the basics of running Waitress. Be sure to read its documentation and `waitress-serve --help` to understand what features are available.

## Installing

Create a virtualenv, install your application, then install `waitress`.

    $ cd hello-app
    $ python -m venv .venv
    $ . .venv/bin/activate
    $ pip install .  # install your application
    $ pip install waitress

## Running

The only required argument to `waitress-serve` tells it how to load your Flask application. The syntax is `{module}:{app}`. `module` is the dotted import name to the module with your application. `app` is the variable with the application. If you’re using the app factory pattern, use `--call {module}:{factory}` instead.

    # equivalent to 'from hello import app'
    $ waitress-serve --host 127.0.0.1 hello:app

    # equivalent to 'from hello import create_app; create_app()'
    $ waitress-serve --host 127.0.0.1 --call hello:create_app

    Serving on http://127.0.0.1:8080

The `--host` option binds the server to local `127.0.0.1` only.

Logs for each request aren’t shown, only errors are shown. Logging can be configured through the Python interface instead of the command line.

## Binding Externally

Waitress should not be run as root because it would cause your application code to run as root, which is not secure. However, this means it will not be possible to bind to port 80 or 443. Instead, a reverse proxy such as nginx or Apache httpd should be used in front of Waitress.

You can bind to all external IPs on a non-privileged port by not specifying the `--host` option. Don’t do this when using a reverse proxy setup, otherwise it will be possible to bypass the proxy.

`0.0.0.0` is not a valid address to navigate to, you’d use a specific IP address in your browser.