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A modern and efficient OSC Client/Server implementation

Project description


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A modern implementation of OSC for python2/3.

What is OSC.

OpenSoundControl is an UDP based network protocol, that is designed for fast dispatching of time-sensitive messages, as the name suggests, it was designed as a replacement for MIDI, but applies well to other situations. The protocol is simple to use, OSC addresses look like http URLs, and accept various basic types, such as string, float, int, etc. You can think of it basically as an http POST, with less overhead.

You can learn more about OSC on


  • python2.7/3.6+ compatibility (can be relaxed more on the python3 side if needed, but nothing before 2.7 will be supported)
  • fast
  • easy to use
  • robust (returns meaningful errors in case of malformed messages, always do the right thing on correct messages, and by default intercept+log the exceptions raised by callbacks)
  • separation of concerns (message parsing vs communication)
  • sync and async compatibility (threads, asyncio, trio…)
  • clean and easy to read code


  • serialize and parse OSC data types/Messages/Bundles
  • a thread based udp server to open sockets (INET or UNIX) and bind callbacks on osc addresses on them
  • a simple client


pip install oscpy


Server (thread)

from oscpy.server import OSCThreadServer
from time import sleep

def callback(*values):
    print("got values: {}".format(values))

osc = OSCThreadServer()  # See sources for all the arguments

# You can also use an \*nix socket path here
sock = osc.listen(address='', port=8000, default=True)
osc.bind(b'/address', callback)
osc.stop()  # Stop the default socket

osc.stop_all()  # Stop all sockets

# Here the server is still alive, one might call osc.listen() again

osc.terminate_server()  # Request the handler thread to stop looping

osc.join_server()  # Wait for the handler thread to finish pending tasks and exit

or you can use the decorator API.

Server (thread)

from oscpy.server import OSCThreadServer
from time import sleep

osc = OSCThreadServer()
sock = osc.listen(address='', port=8000, default=True)

def callback(*values):
    print("got values: {}".format(values))


Servers are also client, in the sense they can send messages and answer to messages from other servers

from oscpy.server import OSCThreadServer
from time import sleep

osc_1 = OSCThreadServer()

def ping(*values):
    print("ping called")
    if True in values:

osc_2 = OSCThreadServer()

def pong(*values):
    print("pong called")
    osc_2.answer(b'/ping', [True])

osc_2.send_message(b'/ping', [], *osc_1.getaddress())

timeout = time() + 1
while not cont:
    if time() > timeout:
        raise OSError('timeout while waiting for success message.')

Server (async) (TODO!)

from oscpy.server import OSCThreadServer

with OSCAsyncServer(port=8000) as OSC:
    for address, values in OSC.listen():
       if address == b'/example':
            print("got {} on /example".format(values))
            print("unknown address {}".format(address))


from oscpy.client import OSCClient

address = ""
port = 8000

osc = OSCClient(address, port)
for i in range(10):
    osc.send_message(b'/ping', [i])


By default, the server and client take bytes (encoded strings), not unicode strings, for osc addresses as well as osc strings. However, you can pass an encoding parameter to have your strings automatically encoded and decoded by them, so your callbacks will get unicode strings (unicode in python2, str in python3).

osc = OSCThreadServer(encoding='utf8')

values = []

def encoded(*val):
    for v in val:
        assert not isinstance(v, bytes)

    [u'hello world', u'ééééé ààààà'],
    *osc.getaddress(), encoding='utf8')

(u literals added here for clarity).


OSCPy provides an "oscli" util, to help with debugging:

  • oscli dump to listen for messages and dump them
  • oscli send to send messages or bundles to a server

See oscli -h for more information.


  • None values are not allowed in serialization
  • Unix-type sockets must not already exist when you listen() on them


  • real support for timetag (currently only supports optionally dropping late bundles, not delaying those with timetags in the future)
  • support for additional argument types
  • an asyncio-oriented server implementation
  • examples & documentation


Check out our contribution guide and feel free to improve OSCPy.


OSCPy is released under the terms of the MIT License. Please see the LICENSE.txt file.

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