# sm.message.subscribe

Subscribes the calling script instance to receive messages for a given key. Can only be called from server!

**Kind:** Function

**Environments:** Game

## Game

``` { .lua .api-signature }
sm.message.subscribe( messageKey, callbackName )
```

[Open the full Game reference](../Game-Script-Environment/Static-Functions/sm.message.md#subscribe)

**Availability:** Server only

**Parameters:**

| Name | Type | Description |
| --- | --- | --- |
| `messageKey` | string | The message key to subscribe to. |
| `callbackName` | string | The name of the callback function to invoke. |