diff --git a/src/im/ImClient.ts b/src/im/ImClient.ts
index 0dfc597..cf6d5c5 100644
--- a/src/im/ImClient.ts
+++ b/src/im/ImClient.ts
@@ -123,6 +123,8 @@ export class ImClient {
             this.ws?.send(buildStompFrame('SUBSCRIBE', { id, destination: dest }))
           }
         })
+        // Sync offline messages
+        this.sendSync()
         this.emit('connected')
         break
       }
@@ -210,6 +212,22 @@ export class ImClient {
     )
   }
 
+  sync(): void {
+    this.sendSync()
+  }
+
+  private sendSync(): void {
+    if (this.ws?.readyState !== WebSocket.OPEN) return
+    const config = getConfig()
+    this.ws.send(
+      buildStompFrame(
+        'SEND',
+        { destination: '/app/chat.sync', 'content-type': 'application/json' },
+        JSON.stringify({ appId: config.appKey })
+      )
+    )
+  }
+
   subscribe(destination: string): void {
     if (this.subscriptions.has(destination)) return
     this.sendSubscribe(destination)
diff --git a/src/im/api.ts b/src/im/api.ts
index 4d0c699..3a05062 100644
--- a/src/im/api.ts
+++ b/src/im/api.ts
@@ -360,3 +360,51 @@ export function adminGroupReadReceipts(groupId: string, messageIds: string[]): P
     appQuery(),
   )
 }
+
+/* ---------- 批量操作 ---------- */
+export function batchAddFriends(friendIds: string[]): Promise<void> {
+  return http.post<void>('/api/im/friends/batch', { friendIds }, appQuery())
+}
+
+export function batchRemoveFriends(friendIds: string[]): Promise<void> {
+  return http.post<void>('/api/im/friends/batch/remove', { friendIds }, appQuery())
+}
+
+export function batchAcceptFriendRequests(requestIds: string[]): Promise<void> {
+  return http.post<void>('/api/im/friend-requests/batch/accept', { requestIds }, appQuery())
+}
+
+export function batchRejectFriendRequests(requestIds: string[]): Promise<void> {
+  return http.post<void>('/api/im/friend-requests/batch/reject', { requestIds }, appQuery())
+}
+
+export function batchAddGroupMembers(groupId: string, userIds: string[]): Promise<void> {
+  return http.post<void>(`/api/im/groups/${encodeURIComponent(groupId)}/members/batch`, { userIds }, appQuery())
+}
+
+export function batchRemoveGroupMembers(groupId: string, userIds: string[]): Promise<void> {
+  return http.post<void>(`/api/im/groups/${encodeURIComponent(groupId)}/members/batch/remove`, { userIds }, appQuery())
+}
+
+export function batchAcceptGroupJoinRequests(groupId: string, requestIds: string[]): Promise<void> {
+  return http.post<void>(`/api/im/groups/${encodeURIComponent(groupId)}/join-requests/batch/accept`, { requestIds }, appQuery())
+}
+
+export function batchRejectGroupJoinRequests(groupId: string, requestIds: string[]): Promise<void> {
+  return http.post<void>(`/api/im/groups/${encodeURIComponent(groupId)}/join-requests/batch/reject`, { requestIds }, appQuery())
+}
+
+export function modifyGroupMemberInfo(groupId: string, userId: string, nickname?: string, role?: string): Promise<void> {
+  const body: Record<string, string> = {}
+  if (nickname !== undefined) body.nickname = nickname
+  if (role !== undefined) body.role = role
+  return http.put<void>(`/api/im/groups/${encodeURIComponent(groupId)}/members/${encodeURIComponent(userId)}/info`, body, appQuery())
+}
+
+export function offlineMessageCount(): Promise<{ count: number }> {
+  return http.get<{ count: number }>('/api/im/messages/offline/count', appQuery())
+}
+
+export function syncOfflineMessages(): Promise<ImMessage[]> {
+  return http.post<ImMessage[]>('/api/im/messages/offline', undefined, appQuery())
+}
diff --git a/src/index.ts b/src/index.ts
index 7b5aa2c..7a79124 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -50,6 +50,17 @@ export {
   transferGroupOwner,
   updateGroupAttributes,
   updateProfile,
+  batchAddFriends,
+  batchRemoveFriends,
+  batchAcceptFriendRequests,
+  batchRejectFriendRequests,
+  batchAddGroupMembers,
+  batchRemoveGroupMembers,
+  batchAcceptGroupJoinRequests,
+  batchRejectGroupJoinRequests,
+  modifyGroupMemberInfo,
+  offlineMessageCount,
+  syncOfflineMessages,
 } from './im/api'
 export { useIm } from './im/useIm'
 export type {