> ## 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.

# Whiteboard sharing

> How to open a whiteboard in a meeting: embed the page URL from getWhiteBoard() in an iframe, broadcast the sharing status with requestShare(ShareType.WhiteBoard), and restore the whiteboard for members who enter mid-meeting.

The whiteboard in a meeting is an **embedded H5 page** (`iframe`). Stroke sync goes through the whiteboard's own connection and produces no media streams. On top of that, the meeting layer does one more thing: **it manages the "who is sharing the whiteboard right now" status for you**, so you don't have to broadcast it yourself as you would at the SRTC layer.

<Note>
  The whiteboard page's own capabilities (URL parameters, hiding menus, desktop annotation mode, when it's destroyed) are exactly the same as at the SRTC layer; see [SRTC · Whiteboard](/en/rtc/whiteboard). This page only covers how usage differs at the meeting layer.
</Note>

***

### Get the whiteboard URL

You can read it once you've entered the meeting. The SDK has already appended the authorization code, so embed it directly:

```typescript theme={null}
await smeeting.enterRoom(/* ... */);

const url = smeeting.getWhiteBoard();
if (url) {
  const iframe = document.createElement("iframe");
  iframe.src = url;
  iframe.style.cssText = "width:100%;height:100%;border:0";
  boardContainer.appendChild(iframe);
}
```

Whiteboards map one-to-one to meetings—everyone in the same meeting opens the same board. The URL becomes invalid after you exit the meeting.

***

### Start and stop sharing

Whiteboard sharing **only broadcasts a status; it doesn't capture any video**:

```typescript theme={null}
import { ShareType } from "@seastart/smeeting-web-sdk";

// Start: broadcast "I'm sharing the whiteboard" in the meeting
await smeeting.requestShare(ShareType.WhiteBoard);

// Stop
await smeeting.stopShare();
```

Only one member in a meeting can share at a time, and screen sharing and the whiteboard are mutually exclusive. When the host has turned on "sharing disabled for the room", a call from a regular member throws an error.

***

### Respond to someone else's whiteboard sharing

When someone else opens the whiteboard, you receive a room event; use it to show the whiteboard:

```typescript theme={null}
smeeting.onNotifyRoomEvent = (evt: RoomEvent) => {
  switch (evt.type) {
    case CommonRoomEventType.ROOM_SHARE_START:
      if (evt.data.share_type === ShareType.WhiteBoard) {
        showWhiteBoard(smeeting.getWhiteBoard());
      }
      break;
    case CommonRoomEventType.ROOM_SHARE_STOP:
      hideWhiteBoard();
      break;
  }
};
```

**Members who enter mid-meeting don't receive this event**, so check once yourself—the meeting info carries the current sharing status:

```typescript theme={null}
const info = smeeting.getRoomInfo();
if (info?.share_state === ShareType.WhiteBoard) {
  // Someone in the meeting is already sharing the whiteboard, so show it on entry
  showWhiteBoard(smeeting.getWhiteBoard());
}
```

`share_state` values: `0` no sharing, `1` screen sharing, `2` whiteboard; the sharer is `share_uid`.

***

### Related

* [SRTC · Whiteboard](/en/rtc/whiteboard)—whiteboard page URL parameters, embedding in native apps, lifecycle, and destruction
* [Events](/en/meeting/web/events)—full definitions of the sharing-related events
* [SMeeting](/en/meeting/web/api-reference/SMeeting)—method signatures