diff --git a/modem/api_validations.py b/modem/api_validations.py
index 81f9d2d3..e3b50021 100644
--- a/modem/api_validations.py
+++ b/modem/api_validations.py
@@ -3,3 +3,10 @@ import re
 def validate_freedata_callsign(callsign):
     regexp = "^[a-zA-Z]+\d+\w+-\d{1,2}$"
     return re.compile(regexp).match(callsign) is not None
+
+def validate_message_attachment(attachment):
+    for field in ['name', 'type', 'data']:
+        if field not in attachment:
+            raise ValueError(f"Attachment missing '{field}'")
+        if len(attachment[field]) < 1:
+            raise ValueError(f"Attachment has empty '{field}'")
diff --git a/modem/command_message_send.py b/modem/command_message_send.py
new file mode 100644
index 00000000..4915cf5e
--- /dev/null
+++ b/modem/command_message_send.py
@@ -0,0 +1,23 @@
+from command import TxCommand
+import api_validations
+import base64
+from queue import Queue
+from arq_session_iss import ARQSessionISS
+from message_p2p import MessageP2P
+
+class SendMessageCommand(TxCommand):
+    """Command to send a P2P message using an ARQ transfer session
+    """
+
+    def set_params_from_api(self, apiParams):
+        origin = f"{self.config['STATION']['mycall']}-{self.config['STATION']['myssid']}"
+        self.message = MessageP2P.from_api_params(origin, apiParams)
+
+    def transmit(self, modem):
+        iss = ARQSessionISS(self.config, modem, 
+                            self.message.destination, 
+                            self.message.to_payload(), 
+                            self.state_manager)
+        
+        self.state_manager.register_arq_iss_session(iss)
+        iss.start()
diff --git a/modem/message_p2p.py b/modem/message_p2p.py
new file mode 100644
index 00000000..30b7d7a7
--- /dev/null
+++ b/modem/message_p2p.py
@@ -0,0 +1,62 @@
+import datetime
+import api_validations
+import base64
+import json
+import lzma
+
+
+class MessageP2P:
+    def __init__(self, origin: str, destination: str, body: str, attachments: list) -> None:
+        self.timestamp = datetime.datetime.now().isoformat()
+        self.origin = origin
+        self.destination = destination
+        self.body = body
+        self.attachments = attachments
+
+    @classmethod
+    def from_api_params(cls, origin: str, params: dict):
+
+        dxcall = params['dxcall']
+        if not api_validations.validate_freedata_callsign(dxcall):
+            dxcall = f"{dxcall}-0"
+
+        if not api_validations.validate_freedata_callsign(dxcall):
+            raise ValueError(f"Invalid dxcall given ({params['dxcall']})")
+
+        body = params['body']
+        if len(body) < 1:
+            raise ValueError(f"Body cannot be empty")
+
+        attachments = []
+        if 'attachments' in params: 
+            for a in params['attachments']:
+                api_validations.validate_message_attachment(a)
+                attachments.append({
+                    'name': a['name'],
+                    'type': a['type'],
+                    'data': base64.decode(a['data']),
+                })
+
+        return cls(origin, dxcall, body, attachments)
+        
+    def get_id(self) -> str:
+        return f"{self.origin}.{self.destination}.{self.timestamp}"
+    
+    def to_dict(self):
+        """Make a dictionary out of the message data
+        """
+        message = {
+            'id': self.get_id(),
+            'origin': self.origin,
+            'destination': self.destination,
+            'body': self.body,
+            'attachments': self.attachments,
+        }
+        return message
+    
+    def to_payload(self):
+        """Make a byte array ready to be sent out of the message data"""
+        json_string = json.dumps(self.to_dict())
+        json_bytes = bytes(json_string, 'utf-8')
+        final_payload = lzma.compress(json_bytes)
+        return final_payload
diff --git a/modem/server.py b/modem/server.py
index 3a5e0971..7e55723b 100644
--- a/modem/server.py
+++ b/modem/server.py
@@ -16,6 +16,7 @@ import command_ping
 import command_feq
 import command_test
 import command_arq_raw
+import command_message_send
 import event_manager
 
 app = Flask(__name__)
@@ -234,6 +235,13 @@ def get_post_radio():
     elif request.method == 'GET':
         return api_response(app.state_manager.get_radio_status())
 
+@app.route('/freedata/messages', methods=['POST'])
+def post_freedata_message():
+    if enqueue_tx_command(command_message_send.SendMessageCommand, request.json):
+        return api_response(request.json)
+    else:
+        api_abort('Error executing command...', 500)
+
 # @app.route('/modem/arq_connect', methods=['POST'])
 # @app.route('/modem/arq_disconnect', methods=['POST'])
 # @app.route('/modem/send_raw', methods=['POST'])
diff --git a/tests/test_message_p2p.py b/tests/test_message_p2p.py
new file mode 100755
index 00000000..f1341e52
--- /dev/null
+++ b/tests/test_message_p2p.py
@@ -0,0 +1,37 @@
+import sys
+sys.path.append('modem')
+
+import unittest
+from config import CONFIG
+from message_p2p import MessageP2P
+
+class TestDataFrameFactory(unittest.TestCase):
+
+    @classmethod
+    def setUpClass(cls):
+        config_manager = CONFIG('modem/config.ini.example')
+        cls.config = config_manager.read()
+        cls.mycall = f"{cls.config['STATION']['mycall']}-{cls.config['STATION']['myssid']}"
+
+
+    def testFromApiParams(self):
+        api_params = {
+            'dxcall': 'DJ2LS-3',
+            'body': 'Hello World!',
+        }
+        message = MessageP2P.from_api_params(self.mycall, api_params)
+        self.assertEqual(message.destination, api_params['dxcall'])
+        self.assertEqual(message.body, api_params['body'])
+
+    def testToPayload(self):
+        api_params = {
+            'dxcall': 'DJ2LS-3',
+            'body': 'Hello World!',
+        }
+        message = MessageP2P.from_api_params(self.mycall, api_params)
+        payload = message.to_payload()
+        self.assertGreater(len(payload), 0)
+        self.assertIsInstance(payload, bytes)
+
+if __name__ == '__main__':
+    unittest.main()