diff --git a/README_API.md b/README_API.md
index 815e9cd..38fcb10 100644
--- a/README_API.md
+++ b/README_API.md
@@ -177,7 +177,7 @@ Remove a previously added listener.
 
 
 ## monarch.post(screen_id, message_id, [message])
-Post a message to a visible screen. If the screen is created through a collection proxy it must have specified a receiver url. If the screen is created through a collection factory the function will post the message to all game objects within the collection.
+Post a message to a visible screen. The screen must have set a message listener using `monarch.on_post()`.
 
 **PARAMETERS**
 * `screen_id` (string|hash) - Id of the screen to post message to
diff --git a/monarch/monarch.lua b/monarch/monarch.lua
index 85426e3..3975619 100644
--- a/monarch/monarch.lua
+++ b/monarch/monarch.lua
@@ -1173,17 +1173,11 @@ function M.post(id, message_id, message)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
 
 	local screen = screens[id]
-	if screen.proxy then
-		if screen.receiver_url then
-			log("post() sending message to", screen.receiver_url)
-			msg.post(screen.receiver_url, message_id, message)
-		else
-			return false, "Unable to post message since screen has no receiver url specified"
-		end
+	if screen.receiver_url then
+		log("post() sending message to", screen.receiver_url)
+		msg.post(screen.receiver_url, message_id, message)
 	else
-		for id,instance in pairs(screen.factory_ids) do
-			msg.post(instance, message_id, message)
-		end
+		return false, "Unable to post message since screen has no receiver url specified. Set one using monarch.on_post()."
 	end
 	return true
 end