diff --git a/src/handlers/teamspeak/connectionHandler.ts b/src/handlers/teamspeak/connectionHandler.ts
index e972d19..985054f 100644
--- a/src/handlers/teamspeak/connectionHandler.ts
+++ b/src/handlers/teamspeak/connectionHandler.ts
@@ -1,11 +1,11 @@
-import { IAuthSenderPayload, IChannel, IClient, IConnection } from "interfaces/teamspeak";
+import { IAuthSenderPayload, IChannel, IClient, IConnection, ITS5Connection } from "interfaces/teamspeak";
 import { TS5DataHandler } from "./dataHandler";
 import { TS5MessageHandler } from "./messageHandler";
 
 
 // Establish connection to TS5 client
 // Main class
-export class TS5Connection {
+export class TS5Connection implements ITS5Connection {
   ws: WebSocket; // Websocket connection to TS5 client
   authenticated = false; // Is the connection authenticated?
   remoteAppPort: number; // Port of TS5 client
diff --git a/src/handlers/teamspeak/dataHandler.ts b/src/handlers/teamspeak/dataHandler.ts
index a268cd7..af96a3d 100644
--- a/src/handlers/teamspeak/dataHandler.ts
+++ b/src/handlers/teamspeak/dataHandler.ts
@@ -1,11 +1,11 @@
-import { IConnection, IChannel, IClient } from "interfaces/teamspeak";
+import { IConnection, IChannel, IClient, ITS5DataHandler } from "interfaces/teamspeak";
 
 
 /**
  * Handles data received from TS5 client (list of connections, channels and clients)
  * Updates the states of App.tsx
  */
-export class TS5DataHandler {
+export class TS5DataHandler implements ITS5DataHandler {
   // Local lists of connections, channels and clients
   // These lists are used to keep track of the data, independent of the App.tsx state
   localConnections: IConnection[];
diff --git a/src/handlers/teamspeak/messageHandler.ts b/src/handlers/teamspeak/messageHandler.ts
index ba5797a..0e922cb 100644
--- a/src/handlers/teamspeak/messageHandler.ts
+++ b/src/handlers/teamspeak/messageHandler.ts
@@ -1,8 +1,8 @@
-import { IChannelInfos, IConnection, IChannel, IAuthMessage, IClientInfo, IClientMovedMessage, IClient, IClientPropertiesUpdatedMessage, ITalkStatusChangedMessage, IClientSelfPropertyUpdatedMessage, IServerPropertiesUpdatedMessage, IConnectStatusChangedMessage, IChannelsMessage } from "interfaces/teamspeak";
+import { IChannelInfos, IConnection, IChannel, IAuthMessage, IClientInfo, IClientMovedMessage, IClient, IClientPropertiesUpdatedMessage, ITalkStatusChangedMessage, IClientSelfPropertyUpdatedMessage, IServerPropertiesUpdatedMessage, IConnectStatusChangedMessage, IChannelsMessage, ITS5MessageHandler } from "interfaces/teamspeak";
 import { TS5DataHandler } from "./dataHandler";
 
 // Handle incoming messages from TS5 client
-export class TS5MessageHandler {
+export class TS5MessageHandler implements ITS5MessageHandler {
   ws: WebSocket;
   dataHandler: TS5DataHandler;
 
diff --git a/src/interfaces/teamspeak.ts b/src/interfaces/teamspeak.ts
index ae5be44..df56675 100644
--- a/src/interfaces/teamspeak.ts
+++ b/src/interfaces/teamspeak.ts
@@ -1,3 +1,54 @@
+// Classes
+export interface ITS5Connection {
+  ws: WebSocket;
+  authenticated: boolean;
+  remoteAppPort: number;
+  dataHandler: ITS5DataHandler;
+  messageHandler: ITS5MessageHandler;
+  reconnect(): void;
+  connect(): void;
+}
+
+export interface ITS5DataHandler {
+  localConnections: IConnection[];
+  localChannels: IChannel[];
+  localClients: IClient[];
+  setConnections: React.Dispatch<React.SetStateAction<IConnection[]>>;
+  setChannels: React.Dispatch<React.SetStateAction<IChannel[]>>;
+  setClients: React.Dispatch<React.SetStateAction<IClient[]>>;
+  clearAll(): void;
+  addConnection(connection: IConnection): void;
+  addChannel(channel: IChannel): void;
+  addClient(client: IClient): void;
+  updateConnection(connection: IConnection): void;
+  updateChannel(channel: IChannel): void;
+  updateClient(client: IClient): void;
+  removeConnection(connection: IConnection): void;
+  removeChannel(channel: IChannel): void;
+  removeClient(client: IClient): void;
+  getConnectionById(id: number): IConnection | undefined;
+  getChannelById(id: number, connectionId: number): IChannel | undefined;
+  getClientById(id: number, connectionId: number): IClient | undefined;
+}
+
+export interface ITS5MessageHandler {
+  ws: WebSocket;
+  dataHandler: ITS5DataHandler;
+  setActiveConnectionStateId: React.Dispatch<React.SetStateAction<number>>;
+  activeConnectionId: number;
+  setActiveConnection(connectionId: number): void;
+  parseChannelInfos(channelInfos: IChannelInfos, connection: IConnection): void;
+  handleAuthMessage(data: IAuthMessage): void;
+  handleClientMovedMessage(data: IClientMovedMessage): void;
+  handleClientPropertiesUpdatedMessage(data: IClientPropertiesUpdatedMessage): void;
+  handleTalkStatusChangedMessage(data: ITalkStatusChangedMessage): void;
+  handleClientSelfPropertyUpdatedMessage(data: IClientSelfPropertyUpdatedMessage): void;
+  handleServerPropertiesUpdatedMessage(data: IServerPropertiesUpdatedMessage): void;
+  handleConnectStatusChangedMessage(data: IConnectStatusChangedMessage): void;
+  handleChannelsMessage(data: IChannelsMessage): void;
+}
+
+// Remote App
 export interface IAuthSenderPayload {
   type: "auth";
   payload: {