New in version 0.8.4: Waitress comes bundled with a thin command-line wrapper around the waitress.serve function called waitress-serve. This is useful for development, and in production situations where serving of static assets is delegated to a reverse proxy, such as nginx or Apache.

waitress-serve takes the very same arguments as the waitress.serve function, but where the function's arguments have underscores, waitress-serve uses hyphens. Thus:

import myapp

waitress.serve(myapp.wsgifunc, port=8041, url_scheme='https')

Is equivalent to:

waitress-serve --port=8041 --url-scheme=https myapp:wsgifunc

The full argument list is given below.

Boolean arguments are represented by flags. If you wish to explicitly set a flag, simply use it by its name. Thus the flag:


Is equivalent to passing expose_tracebacks=True to waitress.serve.

All flags have a negative equivalent. These are prefixed with no-; thus using the flag:


Is equivalent to passing expose_tracebacks=False to waitress.serve.

If at any time you want the full argument list, use the --help flag.

Applications are specified similarly to PasteDeploy, where the format is myapp.mymodule:wsgifunc. As some application frameworks use application objects, you can use dots to resolve attributes like so: myapp.mymodule:appobj.wsgifunc.

A number of frameworks, web.py being an example, have factory methods on their application objects that return usable WSGI functions when called. For cases like these, waitress-serve has the --call flag. Thus:

waitress-serve --call myapp.mymodule.app.wsgi_factory

Would load the myapp.mymodule module, and call app.wsgi_factory to get a WSGI application function to be passed to waitress.server.


As of 0.8.6, the current directory is automatically included on sys.path.



waitress-serve [OPTS] MODULE:OBJECT

Common options:

Show this information.
Call the given object to get the WSGI application.
Hostname or IP address on which to listen, default is '', which means "all IP addresses on this host".
TCP port on which to listen, default is '8080'

Tell waitress to listen on an ip port combination.


--listen= --listen=[::1]:8080 --listen=*:8080

This option may be used multiple times to listen on multipe sockets. A wildcard for the hostname is also supported and will bind to both IPv4/IPv6 depending on whether they are enabled or disabled.


Toggle on/off IPv4 support.

This affects wildcard matching when listening on a wildcard address/port combination.


Toggle on/off IPv6 support.

This affects wildcard matching when listening on a wildcard address/port combination.


Path of Unix socket. If a socket path is specified, a Unix domain socket is made instead of the usual inet domain socket.

Not available on Windows.

Octal permissions to use for the Unix domain socket, default is '600'.
Default wsgi.url_scheme value, default is 'http'.
The SCRIPT_NAME WSGI environment value. Setting this to anything except the empty string will cause the WSGI SCRIPT_NAME value to be the value passed minus any trailing slashes you add, and it will cause the PATH_INFO of any request which is prefixed with this value to be stripped of the prefix. Default is the empty string.
Server identity used in the 'Server' header in responses. Default is 'waitress'.

Tuning options:

Number of threads used to process application logic, default is 4.
Connection backlog for the server. Default is 1024.
Number of bytes to request when calling socket.recv(). Default is 8192.

Number of bytes to send to socket.send(). Default is 1. Multiples of 9000 should avoid partly-filled TCP packets.

Deprecated since version 1.3.

A temporary file should be created if the pending output is larger than this. Default is 1048576 (1MB).
The app_iter will pause when pending output is larger than this value and will resume once enough data is written to the socket to fall below this threshold. Default is 16777216 (16MB).
A temporary file should be created if the pending input is larger than this. Default is 524288 (512KB).
Stop creating new channels if too many are already active. Default is 100.
Minimum seconds between cleaning up inactive channels. Default is 30. See --channel-timeout.
Maximum number of seconds to leave inactive connections open. Default is 120. 'Inactive' is defined as 'has received no data from the client and has sent no data to the client'.
Toggle whether premature client disconnect tracebacks ought to be logged. On by default.
Maximum size of all request headers combined. Default is 262144 (256KB).
Maximum size of request body. Default is 1073741824 (1GB).
Toggle whether to expose tracebacks of unhandled exceptions to the client. Off by default.
The timeout value in seconds passed to asyncore.loop(). Default is 1.
The use_poll argument passed to asyncore.loop(). Helps overcome open file descriptors limit. Default is False.