> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hop.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Sending Messages to Hop Channels

> Along with Channel State, the other primary function of Channels is the ability to send messages to Channel subscribers in realtime.

Messages can be sent to channels from your backend (e.g. an API, a serverless
function, etc) and be received by Channel subscribers (on your frontend app, for
example).

## Message Structure

When sending a message to a channel, you must specify 2 fields:

* an **event name**, and
* message data

The event name can be an arbritrary string of your choosing - for example, if we
were making a group chat application and wanted to send a channel message when
someone sends a chat message, we might call that event `MESSAGE_CREATE`.

The data field can be any object. In the case of our group chat example, we
might include the message content and author in the data object.

<Info>
  This reference assumes you have already set up the [Hop server-side
  SDK](/sdks/server/js).
</Info>

## Publish a Message to a Channel

```js sending-messages.js theme={null}
// Import your Hop SDK instance
import { hop } from ".";

const channelId = "channel_xxx"; // the channel we want to send a message to

await hop.channels.publishMessage(
  channelId,
  // event name of your choosing
  "MESSAGE_CREATE",
  // event data, this can be any object you want it to be
  {
    content: "Hello Hop Channels!",
    author_name: "Vanilla",
  }
);
```