diff --git a/http2irc.py b/http2irc.py
index dd786b4..5a1b5e3 100644
--- a/http2irc.py
+++ b/http2irc.py
@@ -147,8 +147,8 @@ class MessageQueue:
 		if self._getter is not None:
 			self._getter.set_result(None)
 
-	def putleft_nowait(self, item):
-		self._queue.appendleft(item)
+	def putleft_nowait(self, *item):
+		self._queue.extendleft(reversed(item))
 		if self._getter is not None:
 			self._getter.set_result(None)
 
@@ -166,6 +166,8 @@ class IRCClientProtocol(asyncio.Protocol):
 		self.buffer = b''
 		self.connected = False
 		self.channels = channels # Currently joined/supposed-to-be-joined channels; set(str)
+		self.unconfirmedMessages = []
+		self.pongReceivedEvent = asyncio.Event()
 
 	def connection_made(self, transport):
 		logging.info('Connected')
@@ -176,6 +178,7 @@ class IRCClientProtocol(asyncio.Protocol):
 		self.send(b'USER ' + nickb + b' ' + nickb + b' ' + nickb + b' :' + self.config.irc.real.encode('utf-8'))
 		self.send(b'JOIN ' + ','.join(self.channels).encode('utf-8')) #TODO: Split if too long
 		asyncio.create_task(self.send_messages())
+		asyncio.create_task(self.confirm_messages())
 
 	def update_channels(self, channels: set):
 		channelsToPart = self.channels - channels
@@ -220,10 +223,31 @@ class IRCClientProtocol(asyncio.Protocol):
 			logging.debug(f'{id(self)}: got message: {message!r}')
 			if message is None:
 				break
+			self.unconfirmedMessages.append((channel, message))
 			self.send(b'PRIVMSG ' + channel.encode('utf-8') + b' :' + message.encode('utf-8'))
-			#TODO self.messageQueue.putleft_nowait if delivery fails
 			await asyncio.sleep(1) # Rate limit
 
+	async def confirm_messages(self):
+		while self.connected:
+			await asyncio.wait((asyncio.sleep(60), self.connectionClosedEvent.wait()), return_when = concurrent.futures.FIRST_COMPLETED)  # Confirm once per minute
+			if not self.connected: # Disconnected while sleeping, can't confirm unconfirmed messages, requeue them directly
+				self.messageQueue.putleft_nowait(*self.unconfirmedMessages)
+				self.unconfirmedMessages = []
+				break
+			if not self.unconfirmedMessages:
+				logging.debug(f'{id(self)}: no messages to confirm')
+				continue
+			logging.debug(f'{id(self)}: trying to confirm message delivery')
+			self.pongReceivedEvent.clear()
+			self.send(b'PING :42')
+			await asyncio.wait((asyncio.sleep(5), self.pongReceivedEvent.wait()), return_when = concurrent.futures.FIRST_COMPLETED)
+			logging.debug(f'{id(self)}: message delivery success: {self.pongReceivedEvent.is_set()}')
+			if not self.pongReceivedEvent.is_set():
+				# No PONG received in five seconds, assume connection's dead
+				self.messageQueue.putleft_nowait(*self.unconfirmedMessages)
+				self.transport.close()
+			self.unconfirmedMessages = []
+
 	def data_received(self, data):
 		logging.debug(f'Data received: {data!r}')
 		# Split received data on CRLF. If there's any data left in the buffer, prepend it to the first message and process that.
@@ -241,6 +265,8 @@ class IRCClientProtocol(asyncio.Protocol):
 		logging.info(f'Message received: {message!r}')
 		if message.startswith(b'PING '):
 			self.send(b'PONG ' + message[5:])
+		elif message.startswith(b'PONG '):
+			self.pongReceivedEvent.set()
 
 	def connection_lost(self, exc):
 		logging.info('The server closed the connection')