diff --git a/README.md b/README.md
index eff576a..ae5e2b3 100644
--- a/README.md
+++ b/README.md
@@ -84,11 +84,42 @@ Then resume the steps from above.
 
 ## Usage
 
+On Linux and macOS:
+
 ```shell
-cd src
-python -m robot_interface.main
+PYTHONPATH=src python -m robot_interface.main
 ```
 
+On Windows:
+
+```shell
+$env:PYTHONPATH="src"; python -m robot_interface.main
+```
+
+With both, if you want to connect to the actual robot (or simulator), pass the `--qi-url` argument.
+
+
+
+## Testing
+
+To run the unit tests, on Linux and macOS:
+
+```shell
+PYTHONPATH=src pytest test/
+```
+
+On Windows:
+
+```shell
+$env:PYTHONPATH="src"; pytest test/
+```
+
+### Coverage
+
+For coverage, add `--cov=robot_interface` as an argument to `pytest`. 
+
+
+
 ## GitHooks
 
 To activate automatic commits/branch name checks run:
diff --git a/requirements.txt b/requirements.txt
index aee002a..f93c70d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,5 @@
 pyzmq<16
 pyaudio<=0.2.11
+pytest<5
+pytest-mock<3.0.0
+pytest-cov<3.0.0
diff --git a/src/robot_interface/endpoints/actuation_receiver.py b/src/robot_interface/endpoints/actuation_receiver.py
new file mode 100644
index 0000000..7fe16b7
--- /dev/null
+++ b/src/robot_interface/endpoints/actuation_receiver.py
@@ -0,0 +1,49 @@
+import logging
+
+import zmq
+
+from robot_interface.endpoints.receiver_base import ReceiverBase
+from robot_interface.state import state
+
+
+class ActuationReceiver(ReceiverBase):
+    def __init__(self, zmq_context, port=5557):
+        """
+        The actuation receiver endpoint, responsible for handling speech and gesture requests.
+
+        :param zmq_context: The ZeroMQ context to use.
+        :type zmq_context: zmq.Context
+
+        :param port: The port to use.
+        :type port: int
+        """
+        super(ActuationReceiver, self).__init__("actuation")
+        self.create_socket(zmq_context, zmq.SUB, port)
+        self.socket.setsockopt_string(zmq.SUBSCRIBE, u"")  # Causes block if given in options
+        self._tts_service = None
+
+    def _handle_speech(self, message):
+        text = message.get("data")
+        if not text:
+            logging.warn("Received message to speak, but it lacks data.")
+            return
+
+        if not isinstance(text, (str, unicode)):
+            logging.warn("Received message to speak but it is not a string.")
+            return
+
+        logging.debug("Received message to speak: {}".format(text))
+
+        if not state.qi_session: return
+        # If state has a qi_session, we know that we can import qi
+        import qi  # Takes a while only the first time it's imported
+
+        if not self._tts_service:
+            self._tts_service = state.qi_session.service("ALTextToSpeech")
+
+        # Returns instantly. Messages received while speaking will be queued.
+        qi.async(self._tts_service.say, text)
+
+    def handle_message(self, message):
+        if message["endpoint"] == "actuate/speech":
+            self._handle_speech(message)
diff --git a/src/robot_interface/endpoints/main_receiver.py b/src/robot_interface/endpoints/main_receiver.py
index 4ad7846..0ce9711 100644
--- a/src/robot_interface/endpoints/main_receiver.py
+++ b/src/robot_interface/endpoints/main_receiver.py
@@ -1,6 +1,7 @@
 import zmq
 
 from robot_interface.endpoints.receiver_base import ReceiverBase
+from robot_interface.state import state
 
 
 class MainReceiver(ReceiverBase):
@@ -15,13 +16,19 @@ class MainReceiver(ReceiverBase):
         :type port: int
         """
         super(MainReceiver, self).__init__("main")
-        self.create_socket(zmq_context, zmq.REP, port)
+        self.create_socket(zmq_context, zmq.REP, port, bind=False)
 
     @staticmethod
     def _handle_ping(message):
         """A simple ping endpoint. Returns the provided data."""
         return {"endpoint": "ping", "data": message.get("data")}
 
+    @staticmethod
+    def _handle_port_negotiation(message):
+        endpoints = [socket.endpoint_description() for socket in state.sockets]
+
+        return {"endpoint": "negotiate/ports", "data": endpoints}
+
     @staticmethod
     def _handle_negotiation(message):
         """
@@ -33,16 +40,17 @@ class MainReceiver(ReceiverBase):
         :return: A response dictionary with a 'ports' key containing a list of ports and their function.
         :rtype: dict[str, list[dict]]
         """
-        # TODO: .../error on all endpoints?
-        return {"endpoint": "negotiation/error", "data": "The requested endpoint is not implemented."}
+        # In the future, the sender could send information like the robot's IP address, etc.
+
+        if message["endpoint"] == "negotiate/ports":
+            return MainReceiver._handle_port_negotiation(message)
+
+        return {"endpoint": "negotiate/error", "data": "The requested endpoint is not implemented."}
 
     def handle_message(self, message):
-        if "endpoint" not in message:
-            return {"endpoint": "error", "data": "No endpoint provided."}
-
         if message["endpoint"] == "ping":
             return self._handle_ping(message)
-        elif message["endpoint"] == "negotiation":
+        elif message["endpoint"].startswith("negotiate"):
             return self._handle_negotiation(message)
 
         return {"endpoint": "error", "data": "The requested endpoint is not supported."}
diff --git a/src/robot_interface/endpoints/receiver_base.py b/src/robot_interface/endpoints/receiver_base.py
index b3183f7..498d38b 100644
--- a/src/robot_interface/endpoints/receiver_base.py
+++ b/src/robot_interface/endpoints/receiver_base.py
@@ -12,10 +12,10 @@ class ReceiverBase(SocketBase, object):
         """
         Handle a message with the receiver.
 
-        :param message: The message to handle.
+        :param message: The message to handle, must contain properties "endpoint" and "data".
         :type message: dict
 
-        :return: A response message.
-        :rtype: dict
+        :return: A response message or None if this type of receiver doesn't publish.
+        :rtype: dict | None
         """
-        return {"endpoint": "error", "data": "The requested receiver is not implemented."}
+        raise NotImplementedError()
diff --git a/src/robot_interface/endpoints/socket_base.py b/src/robot_interface/endpoints/socket_base.py
index f86b3ec..d08c360 100644
--- a/src/robot_interface/endpoints/socket_base.py
+++ b/src/robot_interface/endpoints/socket_base.py
@@ -1,5 +1,7 @@
 from abc import ABCMeta
 
+import zmq
+
 
 class SocketBase(object):
     __metaclass__ = ABCMeta
@@ -7,15 +9,17 @@ class SocketBase(object):
     name = None
     socket = None
 
-    def __init__(self, name):
+    def __init__(self, identifier):
         """
-        :param name: The name of the endpoint.
-        :type name: str
+        :param identifier: The identifier of the endpoint.
+        :type identifier: str
         """
-        self.name = name
-        self.socket = None
+        self.identifier = identifier
+        self.port = None  # Set later by `create_socket`
+        self.socket = None  # Set later by `create_socket`
+        self.bound = None  # Set later by `create_socket`
 
-    def create_socket(self, zmq_context, socket_type, port, options=[]):
+    def create_socket(self, zmq_context, socket_type, port, options=[], bind=True):
         """
         Create a ZeroMQ socket.
 
@@ -31,16 +35,38 @@ class SocketBase(object):
         :param options: A list of options to be set on the socket. The list contains tuples where the first element contains the option
         and the second the value, for example (zmq.CONFLATE, 1).
         :type options: list[tuple[int, int]]
+
+        :param bind: Whether to bind the socket or connect to it.
+        :type bind: bool
         """
+        self.port = port
         self.socket = zmq_context.socket(socket_type)
 
         for option, arg in options:
             self.socket.setsockopt(option,arg)
 
-        self.socket.connect("tcp://localhost:{}".format(port))
+        self.bound = bind
+        if bind:
+            self.socket.bind("tcp://*:{}".format(port))
+        else:
+            self.socket.connect("tcp://localhost:{}".format(port))
 
     def close(self):
         """Close the ZeroMQ socket."""
         if not self.socket: return
         self.socket.close()
         self.socket = None
+
+    def endpoint_description(self):
+        """
+        Description of the endpoint. Used for negotiation.
+
+        :return: A dictionary with the following keys: id, port, bind. See API specification at:
+        https://utrechtuniversity.youtrack.cloud/articles/N25B-A-14/RI-CB-Communication#negotiation
+        :rtype: dict
+        """
+        return {
+            "id": self.identifier,
+            "port": self.port,
+            "bind": not self.bound
+        }
diff --git a/src/robot_interface/endpoints/video_sender.py b/src/robot_interface/endpoints/video_sender.py
index 793385b..c46b768 100644
--- a/src/robot_interface/endpoints/video_sender.py
+++ b/src/robot_interface/endpoints/video_sender.py
@@ -15,12 +15,12 @@ class VideoSender(SocketBase):
     def start_video_rcv(self):
         """
         Prepares arguments for retrieving video images from Pepper and starts video loop on a separate thread.
-        """        
-        app = qi.Application()
-        app.start()
-        session = app.session
+        """
+        if not state.qi_session:
+            logging.info("No Qi session available. Not starting video loop.")
+            return
 
-        video = session.service("ALVideoDevice")
+        video = state.qi_session.service("ALVideoDevice")
 
         camera_index = 0
         kQVGA = 2
diff --git a/src/robot_interface/main.py b/src/robot_interface/main.py
index fb48040..934dfd3 100644
--- a/src/robot_interface/main.py
+++ b/src/robot_interface/main.py
@@ -1,11 +1,13 @@
 import logging
-import time
+logging.basicConfig(level=logging.DEBUG)
 
 import zmq
 
+from robot_interface.endpoints.actuation_receiver import ActuationReceiver
 from robot_interface.endpoints.main_receiver import MainReceiver
 from robot_interface.endpoints.video_sender import VideoSender
 from robot_interface.state import state
+from robot_interface.utils.timeblock import TimeBlock
 
 
 def main_loop(context):
@@ -18,6 +20,8 @@ def main_loop(context):
     # When creating sockets, remember to add them to the `sockets` list of the state to ensure they're deinitialized
     main_receiver = MainReceiver(context)
     state.sockets.append(main_receiver)
+    actuation_receiver = ActuationReceiver(context)
+    state.sockets.append(actuation_receiver)
 
     video_sender = VideoSender(context)
     state.sockets.append(video_sender)
@@ -25,12 +29,14 @@ def main_loop(context):
     video_sender.start_video_rcv()
 
     # Sockets that can run on the main thread. These sockets' endpoints should not block for long (say 50 ms at most).
-    receivers = [main_receiver]
+    receivers = [main_receiver, actuation_receiver]
 
     poller = zmq.Poller()
     for receiver in receivers:
         poller.register(receiver.socket, zmq.POLLIN)
 
+    logging.debug("Starting main loop.")
+
     while True:
         if state.exit_event.is_set(): break
         socks = dict(poller.poll(100))
@@ -38,15 +44,20 @@ def main_loop(context):
         for receiver in receivers:
             if receiver.socket not in socks: continue
 
-            start_time = time.time()
-
             message = receiver.socket.recv_json()
-            response = receiver.handle_message(message)
-            receiver.socket.send_json(response)
+            if not isinstance(message, dict) or "endpoint" not in message or "data" not in message:
+                logging.error("Received message of unexpected format: {}".format(message))
+                continue
 
-            time_spent_ms = (time.time() - start_time) * 1000
-            if time_spent_ms > 50:
-                logging.warn("Endpoint \"%s\" took too long (%.2f ms) on the main thread.", receiver.name, time_spent_ms)
+            def overtime_callback(time_ms):
+                logging.warn("Endpoint \"%s\" took too long (%.2f ms) on the main thread.",
+                             message["endpoint"], time_ms)
+
+            with TimeBlock(overtime_callback, 50):
+                response = receiver.handle_message(message)
+
+            if receiver.socket.getsockopt(zmq.TYPE) == zmq.REP:
+                receiver.socket.send_json(response)
 
 
 def main():
@@ -57,7 +68,7 @@ def main():
     try:
         main_loop(context)
     except KeyboardInterrupt:
-        print("User interrupted.")
+        logging.info("User interrupted.")
     finally:
         state.deinitialize()
         context.term()
diff --git a/src/robot_interface/state.py b/src/robot_interface/state.py
index d10cf77..b6f8ce1 100644
--- a/src/robot_interface/state.py
+++ b/src/robot_interface/state.py
@@ -2,6 +2,8 @@ import logging
 import signal
 import threading
 
+from robot_interface.utils.qi_utils import get_qi_session
+
 
 class State(object):
     """
@@ -15,6 +17,7 @@ class State(object):
         self.is_initialized = False
         self.exit_event = None
         self.sockets = []  # type: List[SocketBase]
+        self.qi_session = None  # type: None | ssl.SSLSession
 
     def initialize(self):
         if self.is_initialized:
@@ -28,6 +31,8 @@ class State(object):
         signal.signal(signal.SIGINT, handle_exit)
         signal.signal(signal.SIGTERM, handle_exit)
 
+        self.qi_session = get_qi_session()
+
         self.is_initialized = True
 
     def deinitialize(self):
diff --git a/src/robot_interface/utils/__init__.py b/src/robot_interface/utils/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/src/robot_interface/utils/qi_utils.py b/src/robot_interface/utils/qi_utils.py
new file mode 100644
index 0000000..fc7640b
--- /dev/null
+++ b/src/robot_interface/utils/qi_utils.py
@@ -0,0 +1,25 @@
+import logging
+import sys
+
+try:
+    import qi
+except ImportError:
+    qi = None
+
+
+def get_qi_session():
+    if qi is None:
+        logging.info("Unable to import qi. Running in stand-alone mode.")
+        return None
+
+    if "--qi-url" not in sys.argv:
+        logging.info("No Qi URL argument given. Running in stand-alone mode.")
+        return None
+
+    try:
+        app = qi.Application()
+        app.start()
+        return app.session
+    except RuntimeError:
+        logging.info("Unable to connect to the robot. Running in stand-alone mode.")
+        return None
diff --git a/src/robot_interface/utils/timeblock.py b/src/robot_interface/utils/timeblock.py
new file mode 100644
index 0000000..23f1c85
--- /dev/null
+++ b/src/robot_interface/utils/timeblock.py
@@ -0,0 +1,31 @@
+import time
+
+
+class TimeBlock(object):
+    """
+    A context manager that times the execution of the block it contains. If execution exceeds the
+    limit, or if no limit is given, the callback will be called with the time that the block took.
+    """
+    def __init__(self, callback, limit_ms=None):
+        """
+        :param callback: The callback function that is called when the block of code is over,
+        unless the code block did not exceed the time limit.
+        :type callback: Callable[[float], None]
+
+        :param limit_ms: The number of milliseconds the block of code is allowed to take. If it
+        exceeds this time, or if it's None, the callback function will be called with the time the
+        block took.
+        :type limit_ms: int | None
+        """
+        self.limit_ms = float(limit_ms) if limit_ms is not None else None
+        self.callback = callback
+        self.start = None
+
+    def __enter__(self):
+        self.start = time.time()
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        elapsed = (time.time() - self.start) * 1000.0  # ms
+        if self.limit_ms is None or elapsed > self.limit_ms:
+            self.callback(elapsed)
diff --git a/test/unit/__init__.py b/test/unit/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/test/unit/test_actuation_receiver.py b/test/unit/test_actuation_receiver.py
new file mode 100644
index 0000000..da70964
--- /dev/null
+++ b/test/unit/test_actuation_receiver.py
@@ -0,0 +1,74 @@
+import sys
+
+import mock
+import pytest
+import zmq
+
+from robot_interface.endpoints.actuation_receiver import ActuationReceiver
+
+
+@pytest.fixture
+def zmq_context():
+    context = zmq.Context()
+    yield context
+
+
+def test_handle_unimplemented_endpoint(zmq_context):
+    receiver = ActuationReceiver(zmq_context)
+    # Should not error
+    receiver.handle_message({
+        "endpoint": "some_endpoint_that_definitely_does_not_exist",
+        "data": None,
+    })
+
+
+def test_speech_message_no_data(zmq_context, mocker):
+    mock_warn = mocker.patch("logging.warn")
+
+    receiver = ActuationReceiver(zmq_context)
+    receiver.handle_message({"endpoint": "actuate/speech", "data": ""})
+
+    mock_warn.assert_called_with(mock.ANY)
+
+
+def test_speech_message_invalid_data(zmq_context, mocker):
+    mock_warn = mocker.patch("logging.warn")
+
+    receiver = ActuationReceiver(zmq_context)
+    receiver.handle_message({"endpoint": "actuate/speech", "data": True})
+
+    mock_warn.assert_called_with(mock.ANY)
+
+
+def test_speech_no_qi(zmq_context, mocker):
+    mock_state = mocker.patch("robot_interface.endpoints.actuation_receiver.state")
+
+    mock_qi_session = mock.PropertyMock(return_value=None)
+    type(mock_state).qi_session = mock_qi_session
+
+    receiver = ActuationReceiver(zmq_context)
+    receiver._handle_speech({"endpoint": "actuate/speech", "data": "Some message to speak."})
+
+    mock_qi_session.assert_called()
+
+
+def test_speech(zmq_context, mocker):
+    mock_state = mocker.patch("robot_interface.endpoints.actuation_receiver.state")
+
+    mock_qi = mock.Mock()
+    sys.modules["qi"] = mock_qi
+
+    mock_tts_service = mock.Mock()
+    mock_state.qi_session = mock.Mock()
+    mock_state.qi_session.service.return_value = mock_tts_service
+
+    receiver = ActuationReceiver(zmq_context)
+    receiver._tts_service = None
+    receiver._handle_speech({"endpoint": "actuate/speech", "data": "Some message to speak."})
+
+    mock_state.qi_session.service.assert_called_once_with("ALTextToSpeech")
+
+    mock_qi.async.assert_called_once()
+    call_args = mock_qi.async.call_args[0]
+    assert call_args[0] == mock_tts_service.say
+    assert call_args[1] == "Some message to speak."
diff --git a/test/unit/test_main_receiver.py b/test/unit/test_main_receiver.py
new file mode 100644
index 0000000..4ded502
--- /dev/null
+++ b/test/unit/test_main_receiver.py
@@ -0,0 +1,79 @@
+import mock
+import pytest
+import zmq
+
+from robot_interface.endpoints.main_receiver import MainReceiver
+
+
+@pytest.fixture
+def zmq_context():
+    context = zmq.Context()
+    yield context
+
+
+def test_handle_ping(zmq_context):
+    receiver = MainReceiver(zmq_context)
+    response = receiver.handle_message({"endpoint": "ping", "data": "pong"})
+
+    assert "endpoint" in response
+    assert response["endpoint"] == "ping"
+    assert "data" in response
+    assert response["data"] == "pong"
+
+
+def test_handle_ping_none(zmq_context):
+    receiver = MainReceiver(zmq_context)
+    response = receiver.handle_message({"endpoint": "ping", "data": None})
+
+    assert "endpoint" in response
+    assert response["endpoint"] == "ping"
+    assert "data" in response
+    assert response["data"] == None
+
+
+@mock.patch("robot_interface.endpoints.main_receiver.state")
+def test_handle_negotiate_ports(mock_state, zmq_context):
+    receiver = MainReceiver(zmq_context)
+    mock_state.sockets = [receiver]
+
+    response = receiver.handle_message({"endpoint": "negotiate/ports", "data": None})
+
+    assert "endpoint" in response
+    assert response["endpoint"] == "negotiate/ports"
+    assert "data" in response
+    assert isinstance(response["data"], list)
+    for port in response["data"]:
+        assert "id" in port
+        assert isinstance(port["id"], str)
+        assert "port" in port
+        assert isinstance(port["port"], int)
+        assert "bind" in port
+        assert isinstance(port["bind"], bool)
+
+    assert any(port["id"] == "main" for port in response["data"])
+
+
+def test_handle_unimplemented_endpoint(zmq_context):
+    receiver = MainReceiver(zmq_context)
+    response = receiver.handle_message({
+        "endpoint": "some_endpoint_that_definitely_does_not_exist",
+        "data": None,
+    })
+
+    assert "endpoint" in response
+    assert response["endpoint"] == "error"
+    assert "data" in response
+    assert isinstance(response["data"], str)
+
+
+def test_handle_unimplemented_negotiation_endpoint(zmq_context):
+    receiver = MainReceiver(zmq_context)
+    response = receiver.handle_message({
+        "endpoint": "negotiate/but_some_subpath_that_definitely_does_not_exist",
+        "data": None,
+    })
+
+    assert "endpoint" in response
+    assert response["endpoint"] == "negotiate/error"
+    assert "data" in response
+    assert isinstance(response["data"], str)
diff --git a/test/unit/test_time_block.py b/test/unit/test_time_block.py
new file mode 100644
index 0000000..eabc91b
--- /dev/null
+++ b/test/unit/test_time_block.py
@@ -0,0 +1,37 @@
+import time
+
+import mock
+
+from robot_interface.utils.timeblock import TimeBlock
+
+
+class AnyFloat(object):
+    def __eq__(self, other):
+        return isinstance(other, float)
+
+
+def test_no_limit():
+    callback = mock.Mock()
+
+    with TimeBlock(callback):
+        pass
+
+    callback.assert_called_once_with(AnyFloat())
+
+
+def test_exceed_limit():
+    callback = mock.Mock()
+
+    with TimeBlock(callback, 0):
+        time.sleep(0.001)
+
+    callback.assert_called_once_with(AnyFloat())
+
+
+def test_within_limit():
+    callback = mock.Mock()
+
+    with TimeBlock(callback, 5):
+        pass
+
+    callback.assert_not_called()