| Name | Type | Description | Notes |
|---|---|---|---|
| fromUserId | String | Sender user ID. The sender should have an access token. | |
| toUserIds | List<String> | Recipient user IDs. Up to 100 users are supported in a single request. | |
| messageType | String | Message type. Supports built-in types and custom types. Custom types must not start with `RC:` and must not exceed 32 characters. | |
| content | String | Message content payload serialized as a string. Built-in message types should use a JSON object string. Maximum size is 128 KB. | |
| pushContent | String | Push notification text for offline recipients. Required for custom or notification messages that need push delivery. | [optional] |
| pushData | String | Custom push payload data. Exposed as `appData` on iOS and Android. | [optional] |
| shouldPersist | Integer | Whether to store the message in cloud message history. `0` means do not store and `1` means store. | [optional] |
| contentAvailable | Integer | iOS silent-push flag. `1` enables background delivery and `0` disables it. | [optional] |
| disablePush | Boolean | Whether to suppress push notifications for offline recipients. | [optional] |
| pushExt | String | Extended push configuration (JSON string as accepted by `SystemChannelMsgSendInput`). | [optional] |
| disableUpdateLastMsg | Boolean | Whether to keep this message from updating the system channel's last-message preview. | [optional] |