diff --git a/etc/misskey-js.api.md b/etc/misskey-js.api.md
index a2cbb0c2ec..ad5d1bc4be 100644
--- a/etc/misskey-js.api.md
+++ b/etc/misskey-js.api.md
@@ -1177,20 +1177,29 @@ export type Endpoints = {
         res: null;
     };
     'gallery/featured': {
-        req: TODO;
-        res: TODO;
+        req: null;
+        res: GalleryPost[];
     };
     'gallery/popular': {
-        req: TODO;
-        res: TODO;
+        req: null;
+        res: GalleryPost[];
     };
     'gallery/posts': {
-        req: TODO;
-        res: TODO;
+        req: {
+            limit?: number;
+            sinceId?: GalleryPost['id'];
+            untilId?: GalleryPost['id'];
+        };
+        res: GalleryPost[];
     };
     'gallery/posts/create': {
-        req: TODO;
-        res: TODO;
+        req: {
+            title: GalleryPost['title'];
+            description?: GalleryPost['description'];
+            fileIds: GalleryPost['fileIds'];
+            isSensitive?: GalleryPost['isSensitive'];
+        };
+        res: GalleryPost;
     };
     'gallery/posts/delete': {
         req: {
@@ -1199,20 +1208,32 @@ export type Endpoints = {
         res: null;
     };
     'gallery/posts/like': {
-        req: TODO;
-        res: TODO;
+        req: {
+            postId: GalleryPost['id'];
+        };
+        res: null;
     };
     'gallery/posts/show': {
-        req: TODO;
-        res: TODO;
+        req: {
+            postId: GalleryPost['id'];
+        };
+        res: GalleryPost;
     };
     'gallery/posts/unlike': {
-        req: TODO;
-        res: TODO;
+        req: {
+            postId: GalleryPost['id'];
+        };
+        res: null;
     };
     'gallery/posts/update': {
-        req: TODO;
-        res: TODO;
+        req: {
+            postId: GalleryPost['id'];
+            title: GalleryPost['title'];
+            description?: GalleryPost['description'];
+            fileIds: GalleryPost['fileIds'];
+            isSensitive?: GalleryPost['isSensitive'];
+        };
+        res: GalleryPost;
     };
     'games/reversi/games': {
         req: TODO;
@@ -2224,7 +2245,20 @@ type FollowRequest = {
 };
 
 // @public (undocumented)
-type GalleryPost = TODO_2;
+type GalleryPost = {
+    id: ID;
+	createdAt: DateString;
+	updatedAt: DateString;
+	userId: User['id'];
+	user: User;
+	title: string;
+	description: string | null;
+	fileIds: DriveFile['id'][];
+	files: DriveFile[];
+	isSensitive: boolean;
+	likedCount: number;
+	isLiked?: boolean;
+};
 
 // @public (undocumented)
 type ID = string;
diff --git a/src/api.types.ts b/src/api.types.ts
index 2a08af7d64..4fbf42f917 100644
--- a/src/api.types.ts
+++ b/src/api.types.ts
@@ -317,15 +317,15 @@ export type Endpoints = {
 	'following/requests/reject': { req: { userId: User['id'] }; res: null; };
 
 	// gallery
-	'gallery/featured': { req: TODO; res: TODO; };
-	'gallery/popular': { req: TODO; res: TODO; };
-	'gallery/posts': { req: TODO; res: TODO; };
-	'gallery/posts/create': { req: TODO; res: TODO; };
+	'gallery/featured': { req: null; res: GalleryPost[]; };
+	'gallery/popular': { req: null; res: GalleryPost[]; };
+	'gallery/posts': { req: { limit?: number; sinceId?: GalleryPost['id']; untilId?: GalleryPost['id']; }; res: GalleryPost[]; };
+	'gallery/posts/create': { req: { title: GalleryPost['title']; description?: GalleryPost['description']; fileIds: GalleryPost['fileIds']; isSensitive?: GalleryPost['isSensitive'] }; res: GalleryPost; };
 	'gallery/posts/delete': { req: { postId: GalleryPost['id'] }; res: null; };
-	'gallery/posts/like': { req: TODO; res: TODO; };
-	'gallery/posts/show': { req: TODO; res: TODO; };
-	'gallery/posts/unlike': { req: TODO; res: TODO; };
-	'gallery/posts/update': { req: TODO; res: TODO; };
+	'gallery/posts/like': { req: { postId: GalleryPost['id'] }; res: null; };
+	'gallery/posts/show': { req: { postId: GalleryPost['id'] }; res: GalleryPost; };
+	'gallery/posts/unlike': { req: { postId: GalleryPost['id'] }; res: null; };
+	'gallery/posts/update': { req: { postId: GalleryPost['id']; title: GalleryPost['title']; description?: GalleryPost['description']; fileIds: GalleryPost['fileIds']; isSensitive?: GalleryPost['isSensitive'] }; res: GalleryPost; };
 
 	// games
 	'games/reversi/games': { req: TODO; res: TODO; };
diff --git a/src/entities.ts b/src/entities.ts
index 7acffa32e7..37a8bc6184 100644
--- a/src/entities.ts
+++ b/src/entities.ts
@@ -123,7 +123,20 @@ export type DriveFile = {
 
 export type DriveFolder = TODO;
 
-export type GalleryPost = TODO;
+export type GalleryPost = {
+	id: ID;
+	createdAt: DateString;
+	updatedAt: DateString;
+	userId: User['id'];
+	user: User;
+	title: string;
+	description: string | null;
+	fileIds: DriveFile['id'][];
+	files: DriveFile[];
+	isSensitive: boolean;
+	likedCount: number;
+	isLiked?: boolean;
+};
 
 export type Note = {
 	id: ID;