diff --git a/change.ts b/change.ts
index 4bf19bb..2875b43 100644
--- a/change.ts
+++ b/change.ts
@@ -1,4 +1,17 @@
-import type { BasePage, LineId, StringLc } from "./base.ts";
+import type { LineId, StringLc } from "./base.ts";
+import type {
+  ChangeLine,
+  CharsCountChange,
+  DeleteChange,
+  DescriptionsChange,
+  FilesChange,
+  HelpFeelsChange,
+  ImageChange,
+  InfoboxDefinitionChange,
+  InsertChange,
+  LinesCountChange,
+  PinChange,
+} from "./websocket/change.ts";
 
 /** ページの変更内容 */
 export type Change =
@@ -6,31 +19,18 @@ export type Change =
   | UpdateChange
   | DeleteChange
   | LinksChange
+  | ProjectLinksChange
+  | IconsChange
   | DescriptionsChange
   | ImageChange
+  | FilesChange
+  | HelpFeelsChange
+  | InfoboxDefinitionChange
   | TitleChange
+  | LinesCountChange
+  | CharsCountChange
   | PinChange;
 
-/** 行を新規作成する変更 */
-export interface InsertChange {
-  /** このIDが示す行の上に挿入する
-   *
-   * 末尾に挿入するときは`"_end"`を指定する
-   */
-  _insert: LineId;
-
-  /** 挿入する行のデータ */
-  lines: NewLine;
-}
-
-export interface NewLine {
-  /** 新しく挿入する行のID */
-  id: LineId;
-
-  /** 行のテキスト */
-  text: string;
-}
-
 /** 既存の行を書き換える変更 */
 export interface UpdateChange {
   /** 書き換える行のID */
@@ -40,23 +40,6 @@ export interface UpdateChange {
   lines: ChangeLine;
 }
 
-export interface ChangeLine {
-  /**変更前の文字列*/
-  origText: string;
-
-  /**変更後の文字列*/
-  text: string;
-}
-
-/** 既存の行を削除する変更 */
-export interface DeleteChange {
-  /** 削除する行のID */
-  _delete: LineId;
-
-  /** 常に `-1` */
-  lines: -1;
-}
-
 /** ページ中のリンクが変更されると発生する */
 export interface LinksChange {
   /** 新しいリンク */
@@ -66,19 +49,22 @@ export interface LinksChange {
   linksLc: StringLc[];
 }
 
-/** ページのサムネイル本文が変更されると発生する */
-export interface DescriptionsChange {
-  /** 新しいサムネイル本文 */
-  descriptions: string[];
+/** ページ中のproject linksが変更されると発生する */
+export interface ProjectLinksChange {
+  /** 新しいリンク */
+  projectLinks: string[];
+
+  /** 新しいリンク */
+  projectLinksLc: StringLc[];
 }
 
-/** ページのサムネイルが変更されると発生する */
-export interface ImageChange {
-  /** 新しいサムネイルのURL
-   *
-   * サムネイルがなくなったときは`null`になる
-   */
-  image: string | null;
+/** ページ中のiconsが変更されると発生する */
+export interface IconsChange {
+  /** 新しいicons */
+  icons: string[];
+
+  /** 新しいicons */
+  iconsLc: StringLc[];
 }
 
 /** ページのタイトルが変更されると発生する */
@@ -89,8 +75,3 @@ export interface TitleChange {
   /** 新しいタイトル */
   titleLc: StringLc;
 }
-
-/** ページのピンの状態が変更されると発生する */
-export interface PinChange {
-  pin: BasePage["pin"];
-}
diff --git a/deno.jsonc b/deno.jsonc
index 22f3763..86071f1 100644
--- a/deno.jsonc
+++ b/deno.jsonc
@@ -5,14 +5,15 @@
     "fix": "deno fmt && deno lint --fix && deno test --allow-read --doc --parallel --shuffle && deno publish --dry-run --allow-dirty",
     "check": "deno fmt --check && deno lint && deno test --allow-read --doc --parallel --shuffle && deno publish --dry-run",
     "coverage": "deno test --allow-read=./ --parallel --shuffle --coverage && deno coverage --html",
-    "doc": "deno doc --html rest.ts userscript.ts"
+    "doc": "deno doc --html rest.ts userscript.ts websocket.ts"
   },
   "imports": {
     "@std/testing/types": "jsr:@std/testing@0/types"
   },
   "exports": {
     "./rest": "./rest.ts",
-    "./userscript": "./userscript.ts"
+    "./userscript": "./userscript.ts",
+    "./websocket": "./websocket.ts"
   },
   "compilerOptions": {
     "lib": [
diff --git a/deno.lock b/deno.lock
index d3d5329..693553c 100644
--- a/deno.lock
+++ b/deno.lock
@@ -1,17 +1,14 @@
 {
-  "version": "3",
-  "packages": {
-    "specifiers": {
-      "jsr:@std/testing": "jsr:@std/testing@0.225.3",
-      "jsr:@std/testing@0": "jsr:@std/testing@0.225.3"
-    },
-    "jsr": {
-      "@std/testing@0.225.3": {
-        "integrity": "348c24d0479d44ab3dbb4f26170f242e19f24051b45935d4a9e7ca0ab7e37780"
-      }
+  "version": "4",
+  "specifiers": {
+    "jsr:@std/testing@*": "0.225.3",
+    "jsr:@std/testing@0": "0.225.3"
+  },
+  "jsr": {
+    "@std/testing@0.225.3": {
+      "integrity": "348c24d0479d44ab3dbb4f26170f242e19f24051b45935d4a9e7ca0ab7e37780"
     }
   },
-  "remote": {},
   "workspace": {
     "dependencies": [
       "jsr:@std/testing@0"
diff --git a/websocket.ts b/websocket.ts
new file mode 100644
index 0000000..3353cf1
--- /dev/null
+++ b/websocket.ts
@@ -0,0 +1,2 @@
+export * from "./websocket/change.ts";
+export * from "./websocket/event.ts";
diff --git a/websocket/change.ts b/websocket/change.ts
new file mode 100644
index 0000000..dd23c6b
--- /dev/null
+++ b/websocket/change.ts
@@ -0,0 +1,136 @@
+import type { BasePage, LineId } from "../base.ts";
+
+/** Changes to push to the cosense server */
+export type ChangeToPush =
+  | InsertChange
+  | UpdateChange
+  | DeleteChange
+  | LinksChange
+  | ProjectLinksChange
+  | IconsChange
+  | DescriptionsChange
+  | ImageChange
+  | FilesChange
+  | HelpFeelsChange
+  | InfoboxDefinitionChange
+  | TitleChange
+  | LinesCountChange
+  | CharsCountChange
+  | PinChange;
+
+/** 行を新規作成する変更 */
+export interface InsertChange {
+  /** このIDが示す行の上に挿入する
+   *
+   * 末尾に挿入するときは`"_end"`を指定する
+   */
+  _insert: LineId;
+
+  /** 挿入する行のデータ */
+  lines: NewLine;
+}
+export interface NewLine {
+  /** 新しく挿入する行のID */
+  id: LineId;
+
+  /** 行のテキスト */
+  text: string;
+}
+
+export interface UpdateChange {
+  _update: string;
+  lines: Pick<ChangeLine, "text">;
+  noTimestampUpdate?: unknown;
+}
+
+export interface ChangeLine {
+  /**変更前の文字列*/
+  origText: string;
+
+  /**変更後の文字列*/
+  text: string;
+}
+
+/** 既存の行を削除する変更 */
+export interface DeleteChange {
+  /** 削除する行のID */
+  _delete: LineId;
+
+  /** 常に `-1` */
+  lines: -1;
+}
+
+export interface LinksChange {
+  links: string[];
+}
+
+export interface ProjectLinksChange {
+  projectLinks: string[];
+}
+
+export interface IconsChange {
+  icons: string[];
+}
+
+/** ページのサムネイル本文が変更されると発生する */
+export interface DescriptionsChange {
+  /** 新しいサムネイル本文 */
+  descriptions: string[];
+}
+
+/** ページのサムネイルが変更されると発生する */
+export interface ImageChange {
+  /** 新しいサムネイルのURL
+   *
+   * サムネイルがなくなったときは`null`になる
+   */
+  image: string | null;
+}
+
+export interface TitleChange {
+  title: string;
+}
+
+export interface FilesChange {
+  /** Array of file IDs
+   *
+   * These IDs reference files that have been uploaded to the page.
+   * Files can include images, documents, or other attachments.
+   */
+  files: string[];
+}
+export interface HelpFeelsChange {
+  /** Array of Helpfeel entries without the leading "? " prefix
+   *
+   * Helpfeel is a Scrapbox notation for creating help/documentation entries.
+   * Example: "? How to use" becomes "How to use" in this array.
+   * These entries are used to build the page's help documentation.
+   */
+  helpfeels: string[];
+}
+
+export interface InfoboxDefinitionChange {
+  /** Array of trimmed lines from infobox tables
+   *
+   * Contains lines from tables marked with either `table:infobox` or `table:cosense`
+   */
+  infoboxDefinition: string[];
+}
+
+export interface LinesCountChange {
+  linesCount: number;
+}
+
+export interface CharsCountChange {
+  charsCount: number;
+}
+
+/** ページのピンの状態が変更されると発生する */
+export interface PinChange {
+  pin: BasePage["pin"];
+}
+
+export interface DeletePageChange {
+  deleted: true;
+  merged?: true;
+}
diff --git a/websocket/event.ts b/websocket/event.ts
new file mode 100644
index 0000000..6a00217
--- /dev/null
+++ b/websocket/event.ts
@@ -0,0 +1,178 @@
+import type { CommitId, PageId, ProjectId, UserId } from "../base.ts";
+import type { User } from "../response.ts";
+import type {
+  ChangeToPush,
+  DeleteChange,
+  DeletePageChange,
+  DescriptionsChange,
+  IconsChange,
+  ImageChange,
+  InsertChange,
+  LinksChange,
+  TitleChange,
+  UpdateChange,
+} from "./change.ts";
+
+export interface EmitEventMap {
+  "socket.io-request": (
+    req: { method: "commit"; data: PageCommit } | {
+      method: "room:join";
+      data: JoinRoomRequest;
+    },
+    callback: (
+      res:
+        | { data: PageCommitResponse | JoinRoomResponse }
+        | { error: { name: string; message?: string } },
+    ) => void,
+  ) => void;
+  cursor: (req: Omit<MoveCursorData, "socketId">) => void;
+}
+
+export interface PageCommit {
+  kind: "page";
+  parentId: CommitId;
+  projectId: ProjectId;
+  pageId: PageId;
+  userId: UserId;
+  changes: ChangeToPush[] | [DeletePageChange];
+  cursor?: null;
+  freeze: true;
+}
+
+export interface PageCommitResponse {
+  commitId: CommitId;
+}
+
+export type JoinRoomRequest =
+  | JoinPageRoomRequest
+  | JoinProjectRoomRequest
+  | JoinStreamRoomRequest;
+
+export interface JoinProjectRoomRequest {
+  pageId: null;
+  projectId: ProjectId;
+  projectUpdatesStream: false;
+}
+
+export interface JoinPageRoomRequest {
+  pageId: PageId;
+  projectId: ProjectId;
+  projectUpdatesStream: false;
+}
+
+export interface JoinStreamRoomRequest {
+  pageId: null;
+  projectId: ProjectId;
+  projectUpdatesStream: true;
+}
+
+export interface JoinRoomResponse {
+  success: true;
+  pageId: PageId | null;
+  projectId: ProjectId;
+}
+
+export interface MoveCursorData {
+  user: Omit<User, "photo">;
+  pageId: PageId;
+  position: {
+    line: number;
+    char: number;
+  };
+  visible: boolean;
+  socketId: string;
+}
+
+export interface ListenEventMap {
+  "projectUpdatesStream:commit": (event: ProjectUpdatesStreamCommit) => void;
+  "projectUpdatesStream:event": (event: ProjectUpdatesStreamEvent) => void;
+  commit: (event: CommitNotification) => void;
+  cursor: (event: MoveCursorData) => void;
+  "quick-search:commit": (event: QuickSearchCommit) => void;
+  "quick-search:replace-link": QuickSearchReplaceLink;
+  "infobox:updating": boolean;
+  "infobox:reload": void;
+  "literal-database:reload": void;
+}
+
+export interface ProjectUpdatesStreamCommit {
+  kind: "page";
+  id: CommitId;
+  parentId: CommitId;
+  projectId: ProjectId;
+  pageId: PageId;
+  userId: UserId;
+  changes:
+    | (
+      | InsertChange
+      | UpdateChange
+      | DeleteChange
+      | TitleChange
+      | LinksChange
+      | IconsChange
+    )[]
+    | [DeletePageChange];
+  cursor: null;
+  freeze: true;
+}
+
+export type ProjectUpdatesStreamEvent =
+  | PageDeleteEvent
+  | MemberJoinEvent
+  | MemberAddEvent
+  | AdminAddEvent
+  | AdminDeleteEvent
+  | OwnerSetEvent
+  | InvitationResetEvent;
+
+export interface ProjectEvent {
+  id: string;
+  pageId: string;
+  userId: string;
+  projectId: string;
+  created: number;
+  updated: number;
+}
+
+export interface PageDeleteEvent extends ProjectEvent {
+  type: "page.delete";
+  data: {
+    titleLc: string;
+  };
+}
+export interface MemberJoinEvent extends ProjectEvent {
+  type: "member.join";
+}
+export interface MemberAddEvent extends ProjectEvent {
+  type: "member.add";
+}
+export interface InvitationResetEvent extends ProjectEvent {
+  type: "invitation.reset";
+}
+export interface AdminAddEvent extends ProjectEvent {
+  type: "admin.add";
+  targetUserId: UserId;
+}
+export interface AdminDeleteEvent extends ProjectEvent {
+  type: "admin.delete";
+  targetUserId: UserId;
+}
+export interface OwnerSetEvent extends ProjectEvent {
+  type: "owner.set";
+  targetUserId: UserId;
+}
+
+export interface CommitNotification extends PageCommit {
+  id: string;
+}
+
+export interface QuickSearchCommit extends Omit<CommitNotification, "changes"> {
+  changes:
+    | (TitleChange | LinksChange | DescriptionsChange | ImageChange)[]
+    | [DeletePageChange];
+}
+
+export interface QuickSearchReplaceLink {
+  from: string;
+  to: string;
+}