diff --git a/ext/src/lib/messaging.ts b/ext/src/lib/messaging.ts
index 15f63a0..75a2fac 100644
--- a/ext/src/lib/messaging.ts
+++ b/ext/src/lib/messaging.ts
@@ -29,6 +29,8 @@ export type Messages = [
           , availableMediaTypes: ReceiverSelectorMediaType
         }
     }
+  , { subject: "popup:/close" }
+
   , { subject: "receiverSelector:/selected", data: ReceiverSelection }
   , { subject: "receiverSelector:/stop", data: ReceiverSelection }
   , { subject: "main:/shimInitialized", data: { appId: string; }}
@@ -167,6 +169,16 @@ export type Messages = [
         }
       , _id: string;
     }
+  , {
+        subject: "bridge:/mediaServer/start"
+      , data: { filePath: string, port: number }
+    }
+  , {
+        subject: "mediaCast:/mediaServer/started"
+      , data: { mediaPath: string, subtitlePaths: string[] }
+    }
+  , { subject: "mediaCast:/mediaServer/stopped" }
+  , { subject: "mediaCast:/mediaServer/error" }
 
   , { subject: "main:/serviceUp", data: Receiver }
   , { subject: "main:/serviceDown", data: { id: string }}
diff --git a/ext/src/senders/media/index.ts b/ext/src/senders/media/index.ts
index ef586d7..9f58694 100644
--- a/ext/src/senders/media/index.ts
+++ b/ext/src/senders/media/index.ts
@@ -4,7 +4,8 @@ import logger from "../../lib/logger";
 import options from "../../lib/options";
 import cast, { ensureInit } from "../../shim/export";
 
-import { Message, Receiver } from "../../types";
+import { Message } from "../../lib/messaging";
+import { Receiver } from "../../types";
 
 
 function getLocalAddress () {
@@ -35,7 +36,7 @@ function startMediaServer (filePath: string, port: number)
                 filePath: decodeURI(filePath)
               , port
             }
-        });
+        } as Message);
 
         backgroundPort.addEventListener("message", function onMessage (ev) {
             const message = ev.data as Message;
diff --git a/ext/src/types.ts b/ext/src/types.ts
index e66e3fb..7ecac96 100644
--- a/ext/src/types.ts
+++ b/ext/src/types.ts
@@ -1,11 +1,5 @@
 "use strict";
 
-export interface Message {
-    subject: string;
-    data?: any;
-    _id?: string;
-}
-
 export interface Receiver {
     host: string;
     friendlyName: string;
diff --git a/ext/src/ui/popup/index.tsx b/ext/src/ui/popup/index.tsx
index 6a972e1..d463182 100755
--- a/ext/src/ui/popup/index.tsx
+++ b/ext/src/ui/popup/index.tsx
@@ -6,8 +6,9 @@ import ReactDOM from "react-dom";
 
 import knownApps from "../../lib/knownApps";
 
+import { Message } from "../../lib/messaging";
 import { getNextEllipsis } from "../../lib/utils";
-import { Message, Receiver } from "../../types";
+import { Receiver } from "../../types";
 
 import { ReceiverSelectorMediaType } from "../../background/receiverSelector";