diff --git a/packages/backend/src/misc/json-schema.ts b/packages/backend/src/misc/json-schema.ts
index 49f35b9b7..176978d35 100644
--- a/packages/backend/src/misc/json-schema.ts
+++ b/packages/backend/src/misc/json-schema.ts
@@ -38,6 +38,7 @@ import { packedFlashSchema } from '@/models/json-schema/flash.js';
 import { packedAnnouncementSchema } from '@/models/json-schema/announcement.js';
 import { packedSigninSchema } from '@/models/json-schema/signin.js';
 import { packedRoleLiteSchema, packedRoleSchema } from '@/models/json-schema/role.js';
+import { packedAdSchema } from '@/models/json-schema/ad.js';
 
 export const refs = {
 	UserLite: packedUserLiteSchema,
@@ -49,6 +50,7 @@ export const refs = {
 	User: packedUserSchema,
 
 	UserList: packedUserListSchema,
+	Ad: packedAdSchema,
 	Announcement: packedAnnouncementSchema,
 	App: packedAppSchema,
 	Note: packedNoteSchema,
diff --git a/packages/backend/src/models/json-schema/ad.ts b/packages/backend/src/models/json-schema/ad.ts
new file mode 100644
index 000000000..649ffcd4d
--- /dev/null
+++ b/packages/backend/src/models/json-schema/ad.ts
@@ -0,0 +1,64 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export const packedAdSchema = {
+	type: 'object',
+	properties: {
+		id: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+			format: 'id',
+			example: 'xxxxxxxxxx',
+		},
+		expiresAt: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+			format: 'date-time',
+		},
+		startsAt: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+			format: 'date-time',
+		},
+		place: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+		},
+		priority: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+		},
+		ratio: {
+			type: 'number',
+			optional: false,
+			nullable: false,
+		},
+		url: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+		},
+		imageUrl: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+		},
+		memo: {
+			type: 'string',
+			optional: false,
+			nullable: false,
+		},
+		dayOfWeek: {
+			type: 'integer',
+			optional: false,
+			nullable: false,
+		},
+	},
+} as const;
diff --git a/packages/backend/src/server/api/endpoints/admin/accounts/find-by-email.ts b/packages/backend/src/server/api/endpoints/admin/accounts/find-by-email.ts
index 7dc9ca830..bc292fd53 100644
--- a/packages/backend/src/server/api/endpoints/admin/accounts/find-by-email.ts
+++ b/packages/backend/src/server/api/endpoints/admin/accounts/find-by-email.ts
@@ -25,6 +25,11 @@ export const meta = {
 			id: 'cb865949-8af5-4062-a88c-ef55e8786d1d',
 		},
 	},
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		ref: 'User',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/create.ts b/packages/backend/src/server/api/endpoints/admin/ad/create.ts
index cbe9727c4..087ae4bef 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/create.ts
@@ -17,6 +17,12 @@ export const meta = {
 
 	requireCredential: true,
 	requireModerator: true,
+	res: {
+		type: 'object',
+		optional: false,
+		nullable: false,
+		ref: 'Ad',
+	},
 } as const;
 
 export const paramDef = {
@@ -63,7 +69,18 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				ad: ad,
 			});
 
-			return ad;
+			return {
+				id: ad.id,
+				expiresAt: ad.expiresAt.toISOString(),
+				startsAt: ad.startsAt.toISOString(),
+				dayOfWeek: ad.dayOfWeek,
+				url: ad.url,
+				imageUrl: ad.imageUrl,
+				priority: ad.priority,
+				ratio: ad.ratio,
+				place: ad.place,
+				memo: ad.memo,
+			};
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/list.ts b/packages/backend/src/server/api/endpoints/admin/ad/list.ts
index 3bda9fcb0..12528917d 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/list.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/list.ts
@@ -16,6 +16,17 @@ export const meta = {
 
 	requireCredential: true,
 	requireModerator: true,
+	res: {
+		type: 'array',
+		optional: false,
+		nullable: false,
+		items: {
+			type: 'object',
+			optional: false,
+			nullable: false,
+			ref: 'Ad',
+		},
+	},
 } as const;
 
 export const paramDef = {
@@ -46,7 +57,18 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 			}
 			const ads = await query.limit(ps.limit).getMany();
 
-			return ads;
+			return ads.map(ad => ({
+				id: ad.id,
+				expiresAt: ad.expiresAt.toISOString(),
+				startsAt: ad.startsAt.toISOString(),
+				dayOfWeek: ad.dayOfWeek,
+				url: ad.url,
+				imageUrl: ad.imageUrl,
+				memo: ad.memo,
+				place: ad.place,
+				priority: ad.priority,
+				ratio: ad.ratio,
+			}));
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
index 360926594..76ff1c6b9 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
@@ -31,6 +31,8 @@ export const meta = {
 			id: 'f7a3462c-4e6e-4069-8421-b9bd4f4c3975',
 		},
 	},
+
+	ref: 'EmojiDetailed',
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts b/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
index 2de85f655..b81d9857d 100644
--- a/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
+++ b/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
@@ -15,6 +15,16 @@ export const meta = {
 	kind: 'read:admin',
 
 	tags: ['admin'],
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				tablename: { type: 'string' },
+				indexname: { type: 'string' },
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/admin/get-user-ips.ts b/packages/backend/src/server/api/endpoints/admin/get-user-ips.ts
index 6a404c0c7..76c32f2a9 100644
--- a/packages/backend/src/server/api/endpoints/admin/get-user-ips.ts
+++ b/packages/backend/src/server/api/endpoints/admin/get-user-ips.ts
@@ -16,6 +16,25 @@ export const meta = {
 
 	requireCredential: true,
 	requireModerator: true,
+	res: {
+		type: 'array',
+		optional: false,
+		nullable: false,
+		items: {
+			type: 'object',
+			optional: false,
+			nullable: false,
+			properties: {
+				ip: { type: 'string' },
+				createdAt: {
+					type: 'string',
+					optional: false,
+					nullable: false,
+					format: 'date-time',
+				},
+			},
+		},
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/admin/roles/users.ts b/packages/backend/src/server/api/endpoints/admin/roles/users.ts
index 53145a32d..6a0f7f998 100644
--- a/packages/backend/src/server/api/endpoints/admin/roles/users.ts
+++ b/packages/backend/src/server/api/endpoints/admin/roles/users.ts
@@ -28,6 +28,20 @@ export const meta = {
 			id: '224eff5e-2488-4b18-b3e7-f50d94421648',
 		},
 	},
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				id: { type: 'string', format: 'misskey:id' },
+				createdAt: { type: 'string', format: 'date-time' },
+				user: { ref: 'UserDetailed' },
+				expiresAt: { type: 'string', format: 'date-time', nullable: true },
+			},
+			required: ['id', 'createdAt', 'user'],
+		},
+	}
 } as const;
 
 export const paramDef = {
@@ -80,7 +94,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				id: assign.id,
 				createdAt: this.idService.parse(assign.id).date.toISOString(),
 				user: await this.userEntityService.pack(assign.user!, me, { detail: true }),
-				expiresAt: assign.expiresAt,
+				expiresAt: assign.expiresAt?.toISOString() ?? null,
 			})));
 		});
 	}
diff --git a/packages/backend/src/server/api/endpoints/endpoint.ts b/packages/backend/src/server/api/endpoints/endpoint.ts
index cecaded20..66ac8f664 100644
--- a/packages/backend/src/server/api/endpoints/endpoint.ts
+++ b/packages/backend/src/server/api/endpoints/endpoint.ts
@@ -11,6 +11,23 @@ export const meta = {
 	requireCredential: false,
 
 	tags: ['meta'],
+
+	res: {
+		type: 'object',
+		nullable: true,
+		properties: {
+			params: {
+				type: 'array',
+				items: {
+					type: 'object',
+					properties: {
+						name: { type: 'string' },
+						type: { type: 'string' },
+					},
+				},
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/federation/stats.ts b/packages/backend/src/server/api/endpoints/federation/stats.ts
index e3ffea7b7..6548142d4 100644
--- a/packages/backend/src/server/api/endpoints/federation/stats.ts
+++ b/packages/backend/src/server/api/endpoints/federation/stats.ts
@@ -18,6 +18,92 @@ export const meta = {
 
 	allowGet: true,
 	cacheSec: 60 * 60,
+
+	res: {
+		type: 'object',
+		optional: false,
+		nullable: false,
+		properties: {
+			topSubInstances: {
+				type: 'array',
+				optional: false,
+				nullable: false,
+				items: {
+					properties: {
+						id: { type: 'string' },
+						firstRetrievedAt: { type: 'string' },
+						host: { type: 'string' },
+						usersCount: { type: 'number' },
+						notesCount: { type: 'number' },
+						followingCount: { type: 'number' },
+						followersCount: { type: 'number' },
+						isNotResponding: { type: 'boolean' },
+						isSuspended: { type: 'boolean' },
+						isBlocked: { type: 'boolean' },
+						softwareName: { type: 'string' },
+						softwareVersion: { type: 'string' },
+						openRegistrations: { type: 'boolean' },
+						name: { type: 'string' },
+						description: { type: 'string' },
+						maintainerName: { type: 'string' },
+						maintainerEmail: { type: 'string' },
+						isSilenced: { type: 'boolean' },
+						iconUrl: { type: 'string' },
+						faviconUrl: { type: 'string' },
+						themeColor: { type: 'string' },
+						infoUpdatedAt: {
+							type: 'string',
+							nullable: true,
+						},
+						latestRequestReceivedAt: {
+							type: 'string',
+							nullable: true,
+						},
+					}
+				},
+			},
+			otherFollowersCount: { type: 'number' },
+			topPubInstances: {
+				type: 'array',
+				optional: false,
+				nullable: false,
+				items: {
+					properties: {
+						id: { type: 'string' },
+						firstRetrievedAt: { type: 'string' },
+						host: { type: 'string' },
+						usersCount: { type: 'number' },
+						notesCount: { type: 'number' },
+						followingCount: { type: 'number' },
+						followersCount: { type: 'number' },
+						isNotResponding: { type: 'boolean' },
+						isSuspended: { type: 'boolean' },
+						isBlocked: { type: 'boolean' },
+						softwareName: { type: 'string' },
+						softwareVersion: { type: 'string' },
+						openRegistrations: { type: 'boolean' },
+						name: { type: 'string' },
+						description: { type: 'string' },
+						maintainerName: { type: 'string' },
+						maintainerEmail: { type: 'string' },
+						isSilenced: { type: 'boolean' },
+						iconUrl: { type: 'string' },
+						faviconUrl: { type: 'string' },
+						themeColor: { type: 'string' },
+						infoUpdatedAt: {
+							type: 'string',
+							nullable: true,
+						},
+						latestRequestReceivedAt: {
+							type: 'string',
+							nullable: true,
+						},
+					}
+				},
+			},
+			otherFollowingCount: { type: 'number' },
+		},
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/fetch-external-resources.ts b/packages/backend/src/server/api/endpoints/fetch-external-resources.ts
index d7b46cc66..6391a2f58 100644
--- a/packages/backend/src/server/api/endpoints/fetch-external-resources.ts
+++ b/packages/backend/src/server/api/endpoints/fetch-external-resources.ts
@@ -32,6 +32,18 @@ export const meta = {
 			id: '693ba8ba-b486-40df-a174-72f8279b56a4',
 		},
 	},
+
+	res: {
+		type: 'object',
+		properties: {
+			type: {
+				type: 'string',
+			},
+			data: {
+				type: 'string',
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/fetch-rss.ts b/packages/backend/src/server/api/endpoints/fetch-rss.ts
index 37859d833..b2dee83fe 100644
--- a/packages/backend/src/server/api/endpoints/fetch-rss.ts
+++ b/packages/backend/src/server/api/endpoints/fetch-rss.ts
@@ -16,6 +16,18 @@ export const meta = {
 	requireCredential: false,
 	allowGet: true,
 	cacheSec: 60 * 3,
+
+	res: {
+		type: 'object',
+		properties: {
+			items: {
+				type: 'array',
+				items: {
+					type: 'object',
+				},
+			}
+		}
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/flash/create.ts b/packages/backend/src/server/api/endpoints/flash/create.ts
index 4fa65ac9a..674f32373 100644
--- a/packages/backend/src/server/api/endpoints/flash/create.ts
+++ b/packages/backend/src/server/api/endpoints/flash/create.ts
@@ -27,6 +27,12 @@ export const meta = {
 
 	errors: {
 	},
+
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		ref: 'Flash',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/get-online-users-count.ts b/packages/backend/src/server/api/endpoints/get-online-users-count.ts
index 8a61168f2..737d637b7 100644
--- a/packages/backend/src/server/api/endpoints/get-online-users-count.ts
+++ b/packages/backend/src/server/api/endpoints/get-online-users-count.ts
@@ -16,6 +16,16 @@ export const meta = {
 	requireCredential: false,
 	allowGet: true,
 	cacheSec: 60 * 1,
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		properties: {
+			count: {
+				type: 'number',
+				nullable: false,
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts b/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
index 6d530aba3..a7be47fd0 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
@@ -32,6 +32,16 @@ export const meta = {
 			id: '798d6847-b1ed-4f9c-b1f9-163c42655995',
 		},
 	},
+
+	res: {
+		type: 'object',
+		nullable: false,
+		optional: false,
+		properties: {
+			id: { type: 'string' },
+			name: { type: 'string' },
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts b/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
index c39005f2d..0fac96d58 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
@@ -36,6 +36,140 @@ export const meta = {
 			id: 'bf32b864-449b-47b8-974e-f9a5468546f1',
 		},
 	},
+
+	res: {
+		type: 'object',
+		nullable: false,
+		optional: false,
+		properties: {
+			rp: {
+				type: 'object',
+				properties: {
+					id: {
+						type: 'string',
+						nullable: true,
+					},
+				},
+			},
+			user: {
+				type: 'object',
+				properties: {
+					id: {
+						type: 'string',
+					},
+					name: {
+						type: 'string',
+					},
+					displayName: {
+						type: 'string',
+					},
+				},
+			},
+			challenge: {
+				type: 'string',
+			},
+			pubKeyCredParams: {
+				type: 'array',
+				items: {
+					type: 'object',
+					properties: {
+						type: {
+							type: 'string',
+						},
+						alg: {
+							type: 'number',
+						},
+					},
+				},
+			},
+			timeout: {
+				type: 'number',
+				nullable: true,
+			},
+			excludeCredentials: {
+				type: 'array',
+				nullable: true,
+				items: {
+					type: 'object',
+					properties: {
+						id: {
+							type: 'string',
+						},
+						type: {
+							type: 'string',
+						},
+						transports: {
+							type: 'array',
+							items: {
+								type: 'string',
+								enum: [
+									"ble",
+									"cable",
+									"hybrid",
+									"internal",
+									"nfc",
+									"smart-card",
+									"usb",
+								],
+							},
+						},
+					},
+				},
+			},
+			authenticatorSelection: {
+				type: 'object',
+				nullable: true,
+				properties: {
+					authenticatorAttachment: {
+						type: 'string',
+						enum: [
+							"cross-platform",
+							"platform",
+						],
+					},
+					requireResidentKey: {
+						type: 'boolean',
+					},
+					userVerification: {
+						type: 'string',
+						enum: [
+							"discouraged",
+							"preferred",
+							"required",
+						],
+					},
+				},
+			},
+			attestation: {
+				type: 'string',
+				nullable: true,
+				enum: [
+					"direct",
+					"enterprise",
+					"indirect",
+					"none",
+				],
+			},
+			extensions: {
+				type: 'object',
+				nullable: true,
+				properties: {
+					appid: {
+						type: 'string',
+						nullable: true,
+					},
+					credProps: {
+						type: 'boolean',
+						nullable: true,
+					},
+					hmacCreateSecret: {
+						type: 'boolean',
+						nullable: true,
+					},
+				},
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/register.ts b/packages/backend/src/server/api/endpoints/i/2fa/register.ts
index b358c812e..cc083cbf7 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/register.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/register.ts
@@ -26,6 +26,19 @@ export const meta = {
 			id: '78d6c839-20c9-4c66-b90a-fc0542168b48',
 		},
 	},
+
+	res: {
+		type: 'object',
+		nullable: false,
+		optional: false,
+		properties: {
+			qr: { type: 'string' },
+			url: { type: 'string' },
+			secret: { type: 'string' },
+			label: { type: 'string' },
+			issuer: { type: 'string' },
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/apps.ts b/packages/backend/src/server/api/endpoints/i/apps.ts
index 09f6540a7..ef89f9318 100644
--- a/packages/backend/src/server/api/endpoints/i/apps.ts
+++ b/packages/backend/src/server/api/endpoints/i/apps.ts
@@ -13,6 +13,37 @@ export const meta = {
 	requireCredential: true,
 
 	secure: true,
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				id: {
+					type: 'string',
+					format: 'misskey:id',
+				},
+				name: {
+					type: 'string',
+				},
+				createdAt: {
+					type: 'string',
+					format: 'date-time',
+				},
+				lastUsedAt: {
+					type: 'string',
+					format: 'date-time',
+				},
+				permission: {
+					type: 'array',
+					uniqueItems: true,
+					items: {
+						type: 'string'
+					},
+				}
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
@@ -50,7 +81,7 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				id: token.id,
 				name: token.name ?? token.app?.name,
 				createdAt: this.idService.parse(token.id).date.toISOString(),
-				lastUsedAt: token.lastUsedAt,
+				lastUsedAt: token.lastUsedAt?.toISOString(),
 				permission: token.permission,
 			})));
 		});
diff --git a/packages/backend/src/server/api/endpoints/i/authorized-apps.ts b/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
index 32061c2aa..a0ed371fb 100644
--- a/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
+++ b/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
@@ -14,6 +14,36 @@ export const meta = {
 	requireCredential: true,
 
 	secure: true,
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				id: {
+					type: 'string',
+					format: 'misskey:id',
+				},
+				name: {
+					type: 'string',
+				},
+				callbackUrl: {
+					type: 'string',
+					nullable: true,
+				},
+				permission: {
+					type: 'array',
+					uniqueItems: true,
+					items: {
+						type: 'string'
+					},
+				},
+				isAuthorized: {
+					type: 'boolean',
+				},
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/move.ts b/packages/backend/src/server/api/endpoints/i/move.ts
index 86b726e05..f3ba720c2 100644
--- a/packages/backend/src/server/api/endpoints/i/move.ts
+++ b/packages/backend/src/server/api/endpoints/i/move.ts
@@ -64,6 +64,10 @@ export const meta = {
 			id: 'b234a14e-9ebe-4581-8000-074b3c215962',
 		},
 	},
+
+	res: {
+		type: 'object',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get-all.ts b/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
index 29fa0a29c..bd6e85a07 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
@@ -9,6 +9,10 @@ import { RegistryApiService } from '@/core/RegistryApiService.js';
 
 export const meta = {
 	requireCredential: true,
+
+	res: {
+		type: 'object',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts b/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
index 5b460b45d..2352beb13 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
@@ -18,6 +18,10 @@ export const meta = {
 			id: '97a1e8e7-c0f7-47d2-957a-92e61256e01a',
 		},
 	},
+
+	res: {
+		type: 'object',
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get.ts b/packages/backend/src/server/api/endpoints/i/registry/get.ts
index e8c28298e..4155a43e0 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get.ts
@@ -18,6 +18,10 @@ export const meta = {
 			id: 'ac3ed68a-62f0-422b-a7bc-d5e09e8f6a6a',
 		},
 	},
+
+	res: {
+		type: 'object',
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts b/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
index 8953ee5d3..b411cdd3d 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
@@ -9,6 +9,10 @@ import { RegistryApiService } from '@/core/RegistryApiService.js';
 
 export const meta = {
 	requireCredential: true,
+
+	res: {
+		type: 'object',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/registry/scopes-with-domain.ts b/packages/backend/src/server/api/endpoints/i/registry/scopes-with-domain.ts
index 1ff994b82..0aca2a26f 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/scopes-with-domain.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/scopes-with-domain.ts
@@ -10,6 +10,28 @@ import { RegistryApiService } from '@/core/RegistryApiService.js';
 export const meta = {
 	requireCredential: true,
 	secure: true,
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				scopes: {
+					type: 'array',
+					items: {
+						type: 'array',
+						items: {
+							type: 'string',
+						}
+					}
+				},
+				domain: {
+					type: 'string',
+					nullable: true,
+				},
+			},
+		},
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/update-email.ts b/packages/backend/src/server/api/endpoints/i/update-email.ts
index a36b3a732..52977f5a0 100644
--- a/packages/backend/src/server/api/endpoints/i/update-email.ts
+++ b/packages/backend/src/server/api/endpoints/i/update-email.ts
@@ -40,6 +40,11 @@ export const meta = {
 			id: 'a2defefb-f220-8849-0af6-17f816099323',
 		},
 	},
+
+	res: {
+		type: 'object',
+		ref: 'UserDetailed',
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/i/webhooks/create.ts b/packages/backend/src/server/api/endpoints/i/webhooks/create.ts
index f00dba4a8..bdc9f9ea8 100644
--- a/packages/backend/src/server/api/endpoints/i/webhooks/create.ts
+++ b/packages/backend/src/server/api/endpoints/i/webhooks/create.ts
@@ -27,6 +27,33 @@ export const meta = {
 			id: '87a9bb19-111e-4e37-81d3-a3e7426453b0',
 		},
 	},
+
+	res: {
+		type: 'object',
+		properties: {
+			id: {
+				type: 'string',
+				format: 'misskey:id'
+			},
+			userId: {
+				type: 'string',
+				format: 'misskey:id',
+			},
+			name: { type: 'string' },
+			on: {
+				type: 'array',
+				items: {
+					type: 'string',
+					enum: webhookEventTypes,
+				}
+			},
+			url: { type: 'string' },
+			secret: { type: 'string' },
+			active: { type: 'boolean' },
+			latestSentAt: { type: 'string', format: 'date-time', nullable: true },
+			latestStatus: { type: 'integer', nullable: true },
+		},
+	},
 } as const;
 
 export const paramDef = {
@@ -73,7 +100,17 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 
 			this.globalEventService.publishInternalEvent('webhookCreated', webhook);
 
-			return webhook;
+			return {
+				id: webhook.id,
+				userId: webhook.userId,
+				name: webhook.name,
+				on: webhook.on,
+				url: webhook.url,
+				secret: webhook.secret,
+				active: webhook.active,
+				latestSentAt: webhook.latestSentAt?.toISOString(),
+				latestStatus: webhook.latestStatus,
+			};
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/i/webhooks/list.ts b/packages/backend/src/server/api/endpoints/i/webhooks/list.ts
index aa8921fe2..afb2d0509 100644
--- a/packages/backend/src/server/api/endpoints/i/webhooks/list.ts
+++ b/packages/backend/src/server/api/endpoints/i/webhooks/list.ts
@@ -5,6 +5,7 @@
 
 import { Inject, Injectable } from '@nestjs/common';
 import { Endpoint } from '@/server/api/endpoint-base.js';
+import { webhookEventTypes } from '@/models/Webhook.js';
 import type { WebhooksRepository } from '@/models/_.js';
 import { DI } from '@/di-symbols.js';
 
@@ -14,6 +15,36 @@ export const meta = {
 	requireCredential: true,
 
 	kind: 'read:account',
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				id: {
+					type: 'string',
+					format: 'misskey:id'
+				},
+				userId: {
+					type: 'string',
+					format: 'misskey:id',
+				},
+				name: { type: 'string' },
+				on: {
+					type: 'array',
+					items: {
+						type: 'string',
+						enum: webhookEventTypes,
+					}
+				},
+				url: { type: 'string' },
+				secret: { type: 'string' },
+				active: { type: 'boolean' },
+				latestSentAt: { type: 'string', format: 'date-time', nullable: true },
+				latestStatus: { type: 'integer', nullable: true },
+			},
+		}
+	}
 } as const;
 
 export const paramDef = {
@@ -33,7 +64,19 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				userId: me.id,
 			});
 
-			return webhooks;
+			return webhooks.map(webhook => (
+				{
+					id: webhook.id,
+					userId: webhook.userId,
+					name: webhook.name,
+					on: webhook.on,
+					url: webhook.url,
+					secret: webhook.secret,
+					active: webhook.active,
+					latestSentAt: webhook.latestSentAt?.toISOString(),
+					latestStatus: webhook.latestStatus,
+				}
+			));
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/i/webhooks/show.ts b/packages/backend/src/server/api/endpoints/i/webhooks/show.ts
index f1294bb5c..5c6dd908b 100644
--- a/packages/backend/src/server/api/endpoints/i/webhooks/show.ts
+++ b/packages/backend/src/server/api/endpoints/i/webhooks/show.ts
@@ -5,6 +5,7 @@
 
 import { Inject, Injectable } from '@nestjs/common';
 import { Endpoint } from '@/server/api/endpoint-base.js';
+import { webhookEventTypes } from '@/models/Webhook.js';
 import type { WebhooksRepository } from '@/models/_.js';
 import { DI } from '@/di-symbols.js';
 import { ApiError } from '../../../error.js';
@@ -23,6 +24,33 @@ export const meta = {
 			id: '50f614d9-3047-4f7e-90d8-ad6b2d5fb098',
 		},
 	},
+
+	res: {
+		type: 'object',
+		properties: {
+			id: {
+				type: 'string',
+				format: 'misskey:id'
+			},
+			userId: {
+				type: 'string',
+				format: 'misskey:id',
+			},
+			name: { type: 'string' },
+			on: {
+				type: 'array',
+				items: {
+					type: 'string',
+					enum: webhookEventTypes,
+				}
+			},
+			url: { type: 'string' },
+			secret: { type: 'string' },
+			active: { type: 'boolean' },
+			latestSentAt: { type: 'string', format: 'date-time', nullable: true },
+			latestStatus: { type: 'integer', nullable: true },
+		},
+	},
 } as const;
 
 export const paramDef = {
@@ -49,7 +77,17 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				throw new ApiError(meta.errors.noSuchWebhook);
 			}
 
-			return webhook;
+			return {
+				id: webhook.id,
+				userId: webhook.userId,
+				name: webhook.name,
+				on: webhook.on,
+				url: webhook.url,
+				secret: webhook.secret,
+				active: webhook.active,
+				latestSentAt: webhook.latestSentAt?.toISOString(),
+				latestStatus: webhook.latestStatus,
+			};
 		});
 	}
 }
diff --git a/packages/backend/src/server/api/endpoints/roles/users.ts b/packages/backend/src/server/api/endpoints/roles/users.ts
index caaa3735e..d304d075b 100644
--- a/packages/backend/src/server/api/endpoints/roles/users.ts
+++ b/packages/backend/src/server/api/endpoints/roles/users.ts
@@ -24,6 +24,25 @@ export const meta = {
 			id: '30aaaee3-4792-48dc-ab0d-cf501a575ac5',
 		},
 	},
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			nullable: false,
+			properties: {
+				id: {
+					type: 'string',
+					format: 'misskey:id'
+				},
+				user: {
+					type: 'object',
+					ref: 'User'
+				},
+			},
+			required: ['id', 'user'],
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/server-info.ts b/packages/backend/src/server/api/endpoints/server-info.ts
index c8cb63e6b..079f2d7f1 100644
--- a/packages/backend/src/server/api/endpoints/server-info.ts
+++ b/packages/backend/src/server/api/endpoints/server-info.ts
@@ -15,6 +15,53 @@ export const meta = {
 	cacheSec: 60 * 1,
 
 	tags: ['meta'],
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		properties: {
+			machine: {
+				type: 'string',
+				nullable: false,
+			},
+			cpu: {
+				type: 'object',
+				nullable: false,
+				properties: {
+					model: {
+						type: 'string',
+						nullable: false,
+					},
+					cores: {
+						type: 'number',
+						nullable: false,
+					},
+				},
+			},
+			mem: {
+				type: 'object',
+				properties: {
+					total: {
+						type: 'number',
+						nullable: false,
+					},
+				},
+			},
+			fs: {
+				type: 'object',
+				nullable: false,
+				properties: {
+					total: {
+						type: 'number',
+						nullable: false,
+					},
+					used: {
+						type: 'number',
+						nullable: false,
+					},
+				},
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/test.ts b/packages/backend/src/server/api/endpoints/test.ts
index 6d6d44f75..949867c57 100644
--- a/packages/backend/src/server/api/endpoints/test.ts
+++ b/packages/backend/src/server/api/endpoints/test.ts
@@ -12,6 +12,30 @@ export const meta = {
 	description: 'Endpoint for testing input validation.',
 
 	requireCredential: false,
+
+	res: {
+		type: 'object',
+		properties: {
+			id: {
+				type: 'string',
+				format: 'misskey:id'
+			},
+			required: {
+				type: 'boolean',
+			},
+			string: {
+				type: 'string',
+			},
+			default: {
+				type: 'string',
+			},
+			nullableDefault: {
+				type: 'string',
+				default: 'hello',
+				nullable: true,
+			},
+		}
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/users/achievements.ts b/packages/backend/src/server/api/endpoints/users/achievements.ts
index e4845d57b..d6ad718df 100644
--- a/packages/backend/src/server/api/endpoints/users/achievements.ts
+++ b/packages/backend/src/server/api/endpoints/users/achievements.ts
@@ -10,6 +10,21 @@ import { DI } from '@/di-symbols.js';
 
 export const meta = {
 	requireCredential: true,
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			properties: {
+				name: {
+					type: 'string',
+				},
+				unlockedAt: {
+					type: 'number',
+				},
+			},
+		},
+	}
 } as const;
 
 export const paramDef = {
diff --git a/packages/backend/src/server/api/endpoints/users/lists/get-memberships.ts b/packages/backend/src/server/api/endpoints/users/lists/get-memberships.ts
index ae8b4e9b8..985141515 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/get-memberships.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/get-memberships.ts
@@ -25,6 +25,35 @@ export const meta = {
 			id: '7bc05c21-1d7a-41ae-88f1-66820f4dc686',
 		},
 	},
+
+	res: {
+		type: 'array',
+		items: {
+			type: 'object',
+			nullable: false,
+			properties: {
+				id: {
+					type: 'string',
+					format: 'misskey:id',
+				},
+				createdAt: {
+					type: 'string',
+					format: 'date-time',
+				},
+				userId: {
+					type: 'string',
+					format: 'misskey:id',
+				},
+				user: {
+					type: 'object',
+					ref: 'User',
+				},
+				withReplies: {
+					type: 'boolean',
+				},
+			},
+		},
+	},
 } as const;
 
 export const paramDef = {