diff --git a/package.json b/package.json
index ebb4d90897..0f93ae03e9 100644
--- a/package.json
+++ b/package.json
@@ -209,6 +209,7 @@
 		"seedrandom": "3.0.5",
 		"sharp": "0.29.0",
 		"speakeasy": "2.0.0",
+		"strict-event-emitter-types": "2.0.0",
 		"stringz": "2.1.0",
 		"style-loader": "3.2.1",
 		"summaly": "2.4.1",
diff --git a/src/server/api/stream/index.ts b/src/server/api/stream/index.ts
index 469f28f11c..13011b193e 100644
--- a/src/server/api/stream/index.ts
+++ b/src/server/api/stream/index.ts
@@ -15,6 +15,7 @@ import { UserProfile } from '@/models/entities/user-profile';
 import { publishChannelStream, publishGroupMessagingStream, publishMessagingStream } from '@/services/stream';
 import { UserGroup } from '@/models/entities/user-group';
 import { PackedNote } from '@/models/repositories/note';
+import { StreamEventEmitter, UserEvent } from './types';
 
 /**
  * Main stream connection
@@ -28,7 +29,7 @@ export default class Connection {
 	public followingChannels: Set<ChannelModel['id']> = new Set();
 	public token?: AccessToken;
 	private wsConnection: websocket.connection;
-	public subscriber: EventEmitter;
+	public subscriber: StreamEventEmitter;
 	private channels: Channel[] = [];
 	private subscribingNotes: any = {};
 	private cachedNotes: PackedNote[] = [];
@@ -57,14 +58,14 @@ export default class Connection {
 			this.updateFollowingChannels();
 			this.updateUserProfile();
 
-			this.subscriber.on(`user:${this.user.id}`, ({ type, body }) => {
-				this.onUserEvent(type, body);
+			this.subscriber.on(`user:${this.user.id}`, (ev) => {
+				this.onUserEvent(ev);
 			});
 		}
 	}
 
 	@autobind
-	private onUserEvent(type: string, body: any) {
+	private onUserEvent({ type, body }: UserEvent) {
 		switch (type) {
 			case 'follow':
 				this.following.add(body.id);
diff --git a/src/server/api/stream/types.ts b/src/server/api/stream/types.ts
new file mode 100644
index 0000000000..92b3f0fdb5
--- /dev/null
+++ b/src/server/api/stream/types.ts
@@ -0,0 +1,50 @@
+import { User } from '@/models/entities/user';
+import { EventEmitter } from 'events';
+import Emitter from 'strict-event-emitter-types';
+import StreamTypes from 'misskey-js/built/streaming.types';
+import { Channel } from '@/models/entities/channel';
+import { UserProfile } from '@/models/entities/user-profile';
+import { PackedUser } from '@/models/repositories/user';
+
+type Payload<T extends (payload: any) => void> = T extends (payload: infer P) => void ? P : never;
+
+// https://stackoverflow.com/questions/49311989/can-i-infer-the-type-of-a-value-using-extends-keyof-type
+type EventUnionFromDictionary<
+	T extends object,
+	U = { [K in keyof T]: { type: K; body: T[K]} }
+> = U[keyof U];
+
+export type BroadcastStream<T extends keyof StreamTypes.BroadcasrEvents> = {
+	name: 'broadcast';
+	type: T;
+	body: Payload<StreamTypes.BroadcasrEvents[T]>;
+};
+
+export interface UserEventTypes {
+	terminate: {};
+	followChannel: Channel;
+	unfollowChannel: Channel;
+	updateUserProfile: UserProfile;
+	mute: User;
+	unmute: User;
+	follow: PackedUser;
+	unfollow: PackedUser;
+	userAdded: PackedUser;
+};
+
+// UserList userRemoved: PackedUser;
+
+export type UserEventName = `user:${User['id']}`;
+export type UserEvent = EventUnionFromDictionary<UserEventTypes>;
+
+interface StreamEvents {
+	'broadcast': <T extends keyof StreamTypes.BroadcasrEvents>(e: BroadcastStream<T>) => void;
+}
+
+interface AuthenticatedStreamEvents {
+	[key: UserEventName]: <T extends keyof UserEventTypes>(e: UserEvent<T>) => void;
+	[key: `mainStream:${User['id']}`]: (e: { type: string; body: any }) => void;
+	[key: `driveStream:${User['id']}`]: (e: { type: string; body: any }) => void;
+}
+
+export type StreamEventEmitter = Emitter<EventEmitter, AuthenticatedStreamEvents & StreamEvents>;
diff --git a/yarn.lock b/yarn.lock
index 8151dfe089..33f9f22454 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -10249,6 +10249,11 @@ streamsearch@0.1.2:
   resolved "https://registry.yarnpkg.com/streamsearch/-/streamsearch-0.1.2.tgz#808b9d0e56fc273d809ba57338e929919a1a9f1a"
   integrity sha1-gIudDlb8Jz2Am6VzOOkpkZoanxo=
 
+strict-event-emitter-types@2.0.0:
+  version "2.0.0"
+  resolved "https://registry.yarnpkg.com/strict-event-emitter-types/-/strict-event-emitter-types-2.0.0.tgz#05e15549cb4da1694478a53543e4e2f4abcf277f"
+  integrity sha512-Nk/brWYpD85WlOgzw5h173aci0Teyv8YdIAEtV+N88nDB0dLlazZyJMIsN6eo1/AR61l+p6CJTG1JIyFaoNEEA==
+
 strict-uri-encode@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/strict-uri-encode/-/strict-uri-encode-1.1.0.tgz#279b225df1d582b1f54e65addd4352e18faa0713"