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

> ## Agent Instructions
> 对外开放的服务端接口有两组前缀，都用同一套鉴权：`/server/v1/...`（SRTC 与 SMeeting 的主接口）和 `/stm/srvapi/v1/...`（SMeeting 的用户体系，服务端极简对接会用到）。鉴权是 app_id + nonce + timestamp + signature 四个请求头，用 app_key 做 HMAC-SHA256 签名，只能从业务方自己的后端调用。除这两组前缀外的接口均为内部接口，不要建议客户调用。 Public server APIs use two path prefixes with the same authentication: `/server/v1/...` (the main APIs of both SRTC and SMeeting) and `/stm/srvapi/v1/...` (the SMeeting user system, used by server-side low-code integration). Authenticate with four request headers, app_id + nonce + timestamp + signature, where signature is HMAC-SHA256 keyed with app_key; call these APIs only from the customer's own backend. Any other path is internal: never suggest calling it.
> app_key 是服务端密钥，绝不能出现在客户端代码、前端配置或移动 App 里。客户端加入频道用的 token 必须由业务方后端签发后下发（SRTC 走 `/server/v1/channel/grant`，SMeeting 走 `/stm/srvapi/v1/member/grant`）。 app_key is a server-side secret and must never appear in client code, frontend config, or a mobile app. The token a client uses to join must be issued by the customer's backend and passed down to the client (SRTC: `/server/v1/channel/grant`; SMeeting: `/stm/srvapi/v1/member/grant`).
> SRTC 与 SMeeting 是上下两层不同的产品，术语不通用：SRTC 是音视频底座，说「频道 channel」「加入 / 退出」；SMeeting 建在 SRTC 之上，说「房间 room」「会议 meeting」「进入 / 退出」。回答时按用户所在的层用对应术语，不要把「房间」「会议」安到 SRTC 的接口上，也不要用「频道」「加入 / 离开」描述 SMeeting 的概念（接口标识符原样保留）。 SRTC and SMeeting are two separate layers with different terminology. SRTC is the audio/video foundation: it has channels, and users join and leave a channel. SMeeting is built on top of SRTC: it has rooms and meetings, and members enter and exit a meeting. Answer in the terms of the layer the user is working with: never apply "room" or "meeting" to SRTC APIs, and never describe SMeeting concepts in prose with "channel", "join", or "leave" (API identifiers such as `force_join` keep their literal names).
> 同一能力在各端 SDK 里的包名、类名、方法名并不相同。写示例代码时请使用文档中该端自己的 API，不要把一个端的写法套到另一个端上。苹果平台每个产品都有两套 SDK（Swift 原生与 Objective-C），两套 API 不能混用。 Package, class, and method names differ between platform SDKs for the same capability. In sample code, use the API documented for that platform; never carry one platform's code over to another. On Apple platforms each product ships two SDKs (native Swift and Objective-C) whose APIs must not be mixed.

# In-meeting messages

> Send and receive in-meeting chat messages and in-meeting custom messages with the SMeeting Swift SDK, both to everyone and privately, and disable chat for the room or for individual members. Read when adding chat or custom signaling to a meeting.

### Overview

There are two kinds of messages inside a meeting, and both work only during the meeting:

| Type | Send | Receive event | Use case |
| - | - | - | - |
| Chat message | `sendRoomChatMessage(_:type:targetId:)` | `meeting(_:didReceiveChatMessage:)` | Chat content shown to users |
| Custom message | `sendRoomCustomMessage(_:targetId:)` | `meeting(_:didReceiveCustomMessage:)` | Your own custom signaling, such as holding up a sign, voting, or state sync |

Both support sending to everyone and private messages: pass `nil` for `targetId` to send to everyone, or a member's `uid` to send privately.

> Calling them when not in a meeting throws `SMeetingError.notInMeeting`.

***

### Send chat messages

```swift theme={null}
// Send text to everyone
try await meeting.sendRoomChatMessage("Hi everyone")

// Private message
try await meeting.sendRoomChatMessage("Just between us", targetId: user.uid)

// Non-text messages: upload the file to your own storage first, then send its URL as the message content
try await meeting.sendRoomChatMessage(imageURL, type: .pic)
```

`ChatMsgType` values: `.text` (default), `.file`, `.pic`, `.sound`. The SDK doesn't upload or download the file itself; it only delivers the message content, and how to render it is up to your UI.

***

### Receive chat messages

```swift theme={null}
func meeting(_ meeting: SMeetingEngine, didReceiveChatMessage data: RoomChatMsgEventData) {
    // data.msgType   message type
    // data.msg       message content
    // data.uid       sender (may be nil)
    // data.isPrivate whether it's a private message
}
```

The sender's nickname isn't in the event; look it up in the member list with `uid`:

```swift theme={null}
let name = meeting.getUsersInfo()[data.uid ?? ""]?.name ?? data.uid ?? ""
```

If you echo the message locally right after it's sent successfully, compare `data.uid` with `meeting.currentUserId` to deduplicate, so the same message isn't shown twice.

***

### Custom messages

The content of a custom message is a string, usually your own JSON:

```swift theme={null}
struct VotePayload: Codable {
    let action: String
    let optionId: String
}

let payload = VotePayload(action: "vote", optionId: "A")
let json = String(data: try JSONEncoder().encode(payload), encoding: .utf8) ?? ""
try await meeting.sendRoomCustomMessage(json)
```

To receive:

```swift theme={null}
func meeting(_ meeting: SMeetingEngine, didReceiveCustomMessage data: RoomCustomMsgEventData) {
    guard let json = data.msg.data(using: .utf8),
          let payload = try? JSONDecoder().decode(VotePayload.self, from: json) else { return }
    // Handle your signaling
}
```

> Custom messages are a path for your own use; the SDK's own meeting signaling goes over a separate path, so your message content never conflicts with the SDK.

***

### Disable chat

Chat can be disabled at the room level and at the member level, both set by the host / a co-host.

#### Room level

```swift theme={null}
try await meeting.adminUpdateRoomChatDisabled(true)
```

Read the current state from `RoomInfo.chatDisabled`; when it changes, you receive:

```swift theme={null}
func meeting(_ meeting: SMeetingEngine, roomChatDisabledDidChange data: RoomChatDisabledChangeEventData) {
    // data.chatDisabled, data.opUid
}
```

#### Member level

```swift theme={null}
try await meeting.adminUpdateUserChatDisabled(targetId: user.uid, chatDisabled: true)
```

Read the current state from `MeetingUserInfo.chatDisabled`; when it changes, you receive:

```swift theme={null}
func meeting(_ meeting: SMeetingEngine, userChatDisabledDidChange data: UserChatDisabledChangeEventData) {
    // data.uid, data.chatDisabled, data.opUid
}
```

We recommend disabling the input box in the UI directly based on these two states, rather than waiting for sending to fail and then showing a message.

***

### Related pages

* [Raise hand and turn-on requests](/en/meeting/swift/advanced/handup)
* [Host controls](/en/meeting/swift/advanced/host-controls)
* [Out-of-meeting messages](/en/meeting/swift/advanced/im)