diff --git a/lib/tunnelbroker/tunnelbroker-context.js b/lib/tunnelbroker/tunnelbroker-context.js
--- a/lib/tunnelbroker/tunnelbroker-context.js
+++ b/lib/tunnelbroker/tunnelbroker-context.js
@@ -2,9 +2,12 @@
 
 import invariant from 'invariant';
 import * as React from 'react';
+import uuid from 'uuid';
 
 import { tunnnelbrokerURL } from '../facts/tunnelbroker.js';
 import type { MessageReceiveConfirmation } from '../types/tunnelbroker/message-receive-confirmation-types.js';
+import type { MessageSentStatus } from '../types/tunnelbroker/message-to-device-request-status-types.js';
+import type { MessageToDeviceRequest } from '../types/tunnelbroker/message-to-device-request-types.js';
 import {
   type TunnelbrokerMessage,
   tunnelbrokerMessageTypes,
@@ -21,6 +24,12 @@
   message: TunnelbrokerMessage,
 ) => mixed;
 
+type PromiseCallbacks = {
+  +resolve: () => void,
+  +reject: (error: string) => void,
+};
+type Promises = { [clientMessageID: string]: PromiseCallbacks };
+
 type TunnelbrokerContextType = {
   +sendMessage: (message: ClientMessageToDevice) => Promise<void>,
   +addListener: (listener: TunnelbrokerSocketListener) => void,
@@ -41,6 +50,7 @@
   const [connected, setConnected] = React.useState(false);
   const listeners = React.useRef<Set<TunnelbrokerSocketListener>>(new Set());
   const socket = React.useRef<?WebSocket>(null);
+  const promises = React.useRef<Promises>({});
 
   React.useEffect(() => {
     if (connected || !initMessage) {
@@ -107,15 +117,53 @@
           messageIDs: [message.messageID],
         };
         socket.current?.send(JSON.stringify(confirmation));
+      } else if (
+        message.type ===
+        tunnelbrokerMessageTypes.MESSAGE_TO_DEVICE_REQUEST_STATUS
+      ) {
+        for (const status: MessageSentStatus of message.clientMessageIDs) {
+          if (status.type === 'Success') {
+            promises.current[status.data]?.resolve();
+            delete promises.current[status.data];
+          } else if (status.type === 'Error') {
+            promises.current[status.data.id]?.reject(status.data.error);
+            delete promises.current[status.data.id];
+          } else if (status.type === 'SerializationError') {
+            console.log('SerializationError for message: ', status.data);
+          } else if (status.type === 'InvalidRequest') {
+            console.log('Tunnelbroker recorded InvalidRequest');
+          }
+        }
       }
     };
 
     socket.current = tunnelbrokerSocket;
   }, [connected, initMessage]);
 
-  const sendMessage: () => Promise<void> = React.useCallback(() => {
-    return new Promise(() => {});
-  }, []);
+  const sendMessage: (message: ClientMessageToDevice) => Promise<void> =
+    React.useCallback(
+      (message: ClientMessageToDevice) => {
+        if (!connected || !socket.current) {
+          throw new Error('Tunnelbroker not connected');
+        }
+        const clientMessageID = uuid.v4();
+        const messageToDevice: MessageToDeviceRequest = {
+          type: tunnelbrokerMessageTypes.MESSAGE_TO_DEVICE_REQUEST,
+          clientMessageID,
+          deviceID: message.deviceID,
+          payload: message.payload,
+        };
+
+        return new Promise((resolve, reject) => {
+          promises.current[clientMessageID] = {
+            resolve,
+            reject,
+          };
+          socket.current?.send(JSON.stringify(messageToDevice));
+        });
+      },
+      [connected],
+    );
 
   const addListener = React.useCallback(
     (listener: TunnelbrokerSocketListener) => {