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MessagingService

Show Deprecated
Not Creatable
Service
Not Replicated

The MessagingService allows game servers in the same game to communicate with each other in real time (< 1 second) using topics. Topics are developer defined strings (1-80 characters) that game servers can send and receive messages.

Delivery is best effort and not guaranteed. Make sure to architect your game so delivery failures are not critical.

Limitations

Note: these limits are subject to change.

LimitMaximum
Size of message 1kB
Messages sent per game server 150 + 60 * (number of players in this game server) per minute
Messages received per topic (10 + 20 * number of servers) per minute
Messages received for entire game (100 + 50 * number of servers) per minute
Subscriptions allowed per game server 5 + 2 * (number of players in this game server)

Cross-Server Messaging explores how to communicate between game servers in greater detail with relevant code samples. Note that Cross-Server Messaging has separate namespaces for live games and Studio, and they can't communicate with each other.

If you want to publish ad-hoc messages to live game servers, you can use the Open Cloud APIs.

Summary

Properties

Methods

PublishAsync(topic: string, message: Variant): void  YIELDS

Invokes the supplied callback whenever a message is pushed to the topic.

SubscribeAsync(topic: string, callback: function): RBXScriptConnection  YIELDS

Begins listening to the given topic.

Events

Properties

Methods

PublishAsync

void
Yields

This function sends the provided message to all subscribers to the topic, triggering their registered callbacks to be invoked.

Yields until the message is received by the backend.

Parameters

topic: string

Determines where the message is sent.

message: Variant

The data to include in the message.


Returns

void

SubscribeAsync

RBXScriptConnection
Yields

This function registers a callback to begin listening to the given topic. The callback is invoked when a topic receives a message. It can be called multiple times for the same topic.

Callback

The callback is invoked with a single argument, a table with the following entries:

FieldSummary
Data Developer supplied payload
Sent Unix time in seconds at which the message was sent

It yields until the subscription is properly registered and returns a connection object.

To unsubscribe, call :Disconnect() on the returned object. Once Disconnect() is called, the callback should never be invoked. Killing the script containing the connections also causes the underlying connect to be unsubscribed.

See also:

Parameters

topic: string

Determines where to listen for messages.

callback: function

Function to be invoked whenever a message is received.


Returns

RBXScriptConnection

Connection that can be used to unsubscribe from the topic.

Code Samples

Subscribing to Cross Server Messages
local MessagingService = game:GetService("MessagingService")

local Players = game:GetService("Players")



local function onPlayerAdded(player)

	--subscribe to the topic

	local topic = "player-" .. player.UserId

	local connection = MessagingService:SubscribeAsync(topic, function(message)

		print("Received message for", player.Name, message.Data)

	end)



	player.AncestryChanged:Connect(function()

		-- unsubscribe from the topic

		connection:Disconnect()

	end)

end



Players.PlayerAdded:Connect(onPlayerAdded)

Events