diff --git a/plugin/core/transport.ts b/plugin/core/transport.ts
new file mode 100644
index 0000000..f729e64
--- /dev/null
+++ b/plugin/core/transport.ts
@@ -0,0 +1,225 @@
+:
+import { WebSocket } from "ws";
+import type { YonexusClientConfig } from "./config.js";
+
+export type ClientConnectionState = 
+  | "idle"
+  | "connecting"
+  | "connected"
+  | "authenticating"
+  | "authenticated"
+  | "disconnecting"
+  | "disconnected"
+  | "error";
+
+export interface ClientTransport {
+  readonly state: ClientConnectionState;
+  readonly isConnected: boolean;
+  readonly isAuthenticated: boolean;
+  connect(): Promise<void>;
+  disconnect(): void;
+  send(message: string): boolean;
+}
+
+export type ClientMessageHandler = (message: string) => void;
+export type ClientStateChangeHandler = (state: ClientConnectionState) => void;
+export type ClientErrorHandler = (error: Error) => void;
+
+export interface ClientTransportOptions {
+  config: YonexusClientConfig;
+  onMessage: ClientMessageHandler;
+  onStateChange?: ClientStateChangeHandler;
+  onError?: ClientErrorHandler;
+}
+
+export class YonexusClientTransport implements ClientTransport {
+  private ws: WebSocket | null = null;
+  private options: ClientTransportOptions;
+  private _state: ClientConnectionState = "idle";
+  private reconnectAttempts = 0;
+  private reconnectTimer: NodeJS.Timeout | null = null;
+  private heartbeatTimer: NodeJS.Timeout | null = null;
+  
+  // Reconnect configuration
+  private readonly maxReconnectAttempts = 10;
+  private readonly baseReconnectDelayMs = 1000;
+  private readonly maxReconnectDelayMs = 30000;
+
+  constructor(options: ClientTransportOptions) {
+    this.options = options;
+  }
+
+  get state(): ClientConnectionState {
+    return this._state;
+  }
+
+  get isConnected(): boolean {
+    return this.ws !== null && this.ws.readyState === WebSocket.OPEN;
+  }
+
+  get isAuthenticated(): boolean {
+    return this._state === "authenticated";
+  }
+
+  async connect(): Promise<void> {
+    if (this.isConnected) {
+      return;
+    }
+
+    this.setState("connecting");
+    const { mainHost } = this.options.config;
+
+    return new Promise((resolve, reject) => {
+      try {
+        this.ws = new WebSocket(mainHost);
+
+        const onOpen = () => {
+          this.setState("connected");
+          this.reconnectAttempts = 0; // Reset on successful connection
+          resolve();
+        };
+
+        const onError = (error: Error) => {
+          this.setState("error");
+          if (this.options.onError) {
+            this.options.onError(error);
+          }
+          reject(error);
+        };
+
+        this.ws.once("open", onOpen);
+        this.ws.once("error", onError);
+
+        this.ws.on("message", (data) => {
+          const message = data.toString("utf8");
+          this.options.onMessage(message);
+        });
+
+        this.ws.on("close", (code: number, reason: Buffer) => {
+          this.handleDisconnect(code, reason.toString());
+        });
+
+        this.ws.on("error", (error: Error) => {
+          if (this.options.onError) {
+            this.options.onError(error);
+          }
+        });
+
+      } catch (error) {
+        this.setState("error");
+        reject(error);
+      }
+    });
+  }
+
+  disconnect(): void {
+    this.clearReconnectTimer();
+    this.stopHeartbeat();
+    
+    if (this.ws) {
+      this.setState("disconnecting");
+      this.ws.close(1000, "Client disconnecting");
+      this.ws = null;
+    }
+    
+    this.setState("disconnected");
+  }
+
+  send(message: string): boolean {
+    if (!this.isConnected) {
+      return false;
+    }
+    
+    try {
+      this.ws!.send(message);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+
+  markAuthenticated(): void {
+    if (this._state === "connected" || this._state === "authenticating") {
+      this.setState("authenticated");
+      this.startHeartbeat();
+    }
+  }
+
+  markAuthenticating(): void {
+    if (this._state === "connected") {
+      this.setState("authenticating");
+    }
+  }
+
+  private handleDisconnect(code: number, reason: string): void {
+    const wasAuthenticated = this._state === "authenticated";
+    this.ws = null;
+    this.stopHeartbeat();
+    this.setState("disconnected");
+
+    // Don't reconnect if it was a normal close
+    if (code === 1000) {
+      return;
+    }
+
+    // Attempt reconnect if we were previously authenticated
+    if (wasAuthenticated && this.reconnectAttempts < this.maxReconnectAttempts) {
+      this.scheduleReconnect();
+    }
+  }
+
+  private scheduleReconnect(): void {
+    this.clearReconnectTimer();
+    
+    const delay = Math.min(
+      this.baseReconnectDelayMs * Math.pow(2, this.reconnectAttempts),
+      this.maxReconnectDelayMs
+    );
+    
+    this.reconnectAttempts++;
+    
+    this.reconnectTimer = setTimeout(() => {
+      this.connect().catch(() => {
+        // Error handled in connect()
+      });
+    }, delay);
+  }
+
+  private clearReconnectTimer(): void {
+    if (this.reconnectTimer) {
+      clearTimeout(this.reconnectTimer);
+      this.reconnectTimer = null;
+    }
+  }
+
+  private startHeartbeat(): void {
+    this.stopHeartbeat();
+    // Heartbeat every 5 minutes (300 seconds)
+    this.heartbeatTimer = setInterval(() => {
+      if (this.isConnected) {
+        // Send heartbeat - actual message construction done by protocol layer
+        this.options.onMessage("heartbeat_tick");
+      }
+    }, 5 * 60 * 1000);
+  }
+
+  private stopHeartbeat(): void {
+    if (this.heartbeatTimer) {
+      clearInterval(this.heartbeatTimer);
+      this.heartbeatTimer = null;
+    }
+  }
+
+  private setState(state: ClientConnectionState): void {
+    const oldState = this._state;
+    this._state = state;
+    
+    if (oldState !== state && this.options.onStateChange) {
+      this.options.onStateChange(state);
+    }
+  }
+}
+
+export function createClientTransport(options: ClientTransportOptions): ClientTransport {
+  return new YonexusClientTransport(options);
+}
diff --git a/plugin/index.ts b/plugin/index.ts
index 502d7ff..266a71d 100644
--- a/plugin/index.ts
+++ b/plugin/index.ts
@@ -14,6 +14,16 @@ export {
   type YonexusClientStateFile,
   type YonexusClientStateStore
 } from "./core/state.js";
+export {
+  createClientTransport,
+  YonexusClientTransport,
+  type ClientTransport,
+  type ClientTransportOptions,
+  type ClientConnectionState,
+  type ClientMessageHandler,
+  type ClientStateChangeHandler,
+  type ClientErrorHandler
+} from "./core/transport.js";
 
 export interface YonexusClientPluginManifest {
   readonly name: "Yonexus.Client";