diff --git a/src/ain.ts b/src/ain.ts
index ac5eb05..18b58d3 100644
--- a/src/ain.ts
+++ b/src/ain.ts
@@ -55,4 +55,9 @@ export default class AinModule {
     this.isDefaultAccountExist();
     return this.ain!.wallet.defaultAccount!.address;
   }
+
+  getEventManager() {
+    this.checkAinInitiated();
+    return this.ain!.em;
+  }
 }
\ No newline at end of file
diff --git a/src/ainize.ts b/src/ainize.ts
index c66ab5f..2b24fe1 100644
--- a/src/ainize.ts
+++ b/src/ainize.ts
@@ -11,7 +11,6 @@ export default class Ainize {
   private cache: NodeCache;
   ain: Ain;
   middleware: Middleware;
-  handler: Handler;
   appController: AppController = AppController.getInstance();
 
   constructor(chainId: 1 | 0) {
@@ -19,7 +18,6 @@ export default class Ainize {
     this.ain = new Ain(blockChainEndpoint, chainId);
     this.cache = new NodeCache();
     this.middleware = new Middleware(this.cache);
-    this.handler = new Handler(this);
   }
   
   // FIXME(yoojin): add config type and change param type.
diff --git a/src/controllers/modelController.ts b/src/controllers/modelController.ts
index 94e9f10..6c5bb3f 100644
--- a/src/controllers/modelController.ts
+++ b/src/controllers/modelController.ts
@@ -3,14 +3,15 @@ import AinModule from "../ain";
 import { Path } from "../constants";
 import { getRequestDepositOp, getTransferOp } from "../utils/operator";
 import { buildSetOperation, buildTxBody } from "../utils/builder";
+import Handler from "../handlers/handler";
 
 export default class ModelController {
   private static instance: ModelController | undefined;
   private ain = AinModule.getInstance();
+  private handler = Handler.getInstance();
   static getInstance() {
     if(!ModelController.instance){
       ModelController.instance = new ModelController();
-
     }
     return ModelController.instance;
   }
@@ -73,13 +74,17 @@ export default class ModelController {
   //TODO(woojae): connect with handler
   async use(modelName: string, requestData: string) {
     this.isLoggedIn();
-    const requestKey = Date.now();
-    const requesterAddress = this.ain.getAddress();
-    const requestPath = Path.app(modelName).request(requesterAddress, requestKey);
-    const requestOp = buildSetOperation("SET_VALUE", requestPath, {prompt: requestData});
-    const txBody = buildTxBody(requestOp);
-    await this.ain.sendTransaction(txBody);
-    return requestKey;
+    const result = await new Promise(async (resolve, reject) => {
+      const requestKey = Date.now();
+      const requesterAddress = this.ain.getAddress();
+      await this.handler.subscribe(requesterAddress, requestKey.toString(), modelName, resolve);
+      const requestPath = Path.app(modelName).request(requesterAddress, requestKey);
+      const requestOp = buildSetOperation("SET_VALUE", requestPath, {prompt: requestData});
+      const txBody = buildTxBody(requestOp);
+      await this.ain.sendTransaction(txBody);
+      return requestKey;
+    });
+    return result;
   }
 
   //TODO(woojae): implement this
diff --git a/src/handlers/handler.ts b/src/handlers/handler.ts
index 725f1e6..9a8c2cd 100644
--- a/src/handlers/handler.ts
+++ b/src/handlers/handler.ts
@@ -1,94 +1,67 @@
 const _ = require("lodash");
 import Ain from "@ainblockchain/ain-js";
-import { HANDLER_HEARBEAT_INTERVAL, Path } from "../constants";
 import Ainize from "../ainize";
+import { Path } from "../constants";
+import AinModule from "../ain";
+import EventManager from "@ainblockchain/ain-js/lib/event-manager";
 
 export default class Handler {
-  isConnected: boolean = false;
-  subscribeTable:any = {};
-  ain: Ain;
-  constructor(ainize: Ainize) {
-    this.ain = ainize.ain;
+  private static instance: Handler | undefined;
+  em = AinModule.getInstance().getEventManager();
+  static getInstance() {
+    if(!Handler.instance){
+      Handler.instance = new Handler();
+    }
+    return Handler.instance;
+  }
+
+  checkEventManager() {
+    if (!this.em) {
+      if(!AinModule.getInstance().getEventManager()){
+        throw new Error('you should init ain first');
+      }
+      this.em = AinModule.getInstance().getEventManager();
+    }
+    return true;
   }
 
-    /**
-   * Connect to ai Network event node. you should connect before subscibe. It will auto reconnect when disconnected. 
-   * @returns Nothing.
-   */
   async connect() {
-    await this.ain.em.connect({}, this.disconnectedCallback.bind(this));
-    this.isConnected = true;
+    this.checkEventManager();
+    await this.em!.connect({},this.disconnectedCb);
+    console.log('connected');
   };
 
-  private async disconnectedCallback() {
-    this.isConnected = false;
+  private async disconnectedCb() {
+    console.log('disconnected. reconnecting...');
     await this.connect();
   }
 
-  /**
-   * Subscribe to specific service reponse. You can handle reponse with callback function.
-   * You should connect before subscibe. 
-   * @param {string} userAddress - Address of account you request with. 
-   * @param {string} appName - App name you want to subscribe.
-   * @param {Function(valueChangedEvent: any)} callback - A callback function to handle response. It will be called when response is written.
-   * @returns SubscribeId. 
-   */
-  async subscribe(userAddress:string, appName: string, callback: (valueChangedEvent: any) => any) {
-    if (this.checkSubscribeTableExists(userAddress, appName)){
-      throw new Error("Already subscribed");
-    }
-    const subscribeId = await this.ain.em.subscribe(
+  async subscribe(requester:string, recordId:string, appName: string, resolve: any) {
+    this.checkEventManager();
+    const responsePath = Path.app(appName).response(requester, recordId);
+    const subscribeId = await this.em!.subscribe(
       "VALUE_CHANGED",
       {
-        path: Path.app(appName).response(userAddress, "$requestKey"),
+        path: responsePath,
         event_source: "USER",
       },
-      (valueChangedEvent) => {
-        callback(valueChangedEvent);
+      (valueChangedEvent: any) => {
+        this.unsubscribe(subscribeId);
+        resolve(valueChangedEvent.values.after.data);
       },
       (err) => {
         throw new Error(err.message);
       },
     );
-    this.addToSubscribeTable(userAddress, appName, subscribeId);
-    return subscribeId;
-  }
-  
-  private checkSubscribeTableExists(userAddress:string, appName:string,) {
-    return _.has(this.subscribeTable, [userAddress, appName]);
-  }
-
-  private addToSubscribeTable(userAddress:string, appName: string, filterId: string) {
-    _.set(this.subscribeTable, [userAddress], {appName:filterId});
   }
 
-  /**
-   * Get subscribe list of userAddress. If you don't set userAddress, it will return all subscribe list.
-   * @param {string=} userAddress - Address of account you want to get subscribe list.
-   * @returns Result of transaction.
-   */
-  getSubscribeList(userAddress?: string) {
-    if (!userAddress) return this.subscribeTable;
-    return this.subscribeTable[userAddress];
-  }
-  /**
-   * Unsubscribe to specific service reponse. 
-   * @param {string} userAddress - Address of account you want to unsubscribe.
-   * @param {string} appName - App name you want to unsubscribe.
-   * @returns True if successfuly unsubscribed.
-   */
-  unsubscribe(userAddress:string, appName: string) {
-    if (!this.checkSubscribeTableExists(userAddress, appName)) {
-      throw new Error("Not subscribed");
-    }
-    this.ain.em.unsubscribe(
-      this.subscribeTable[userAddress][appName],
+  async unsubscribe(filterId: string) {
+    this.checkEventManager();
+    await this.em!.unsubscribe(
+      filterId,
       (err)=>{
         if (err) {
           throw new Error(err.message);
-      } else {
-        this.subscribeTable[userAddress][appName] = null;
-          return true;
       }
     });
   }
diff --git a/src/modules/moduleBase.ts b/src/modules/moduleBase.ts
deleted file mode 100644
index 9767d7f..0000000
--- a/src/modules/moduleBase.ts
+++ /dev/null
@@ -1,46 +0,0 @@
-import Ain from "@ainblockchain/ain-js";
-import { SetOperation, TransactionBody } from "@ainblockchain/ain-js/lib/types";
-import Ainize from "../ainize";
-import { opResult, txResult } from "../types/type";
-
-export default class ModuleBase {
-  protected ain: Ain;
-  constructor(ainize: Ainize) {
-    this.ain = ainize.ain;
-  }
-
-  protected getDefaultAccount() {
-    const defaultAccount = this.ain.wallet.defaultAccount;
-    if (!defaultAccount) 
-      throw new Error("You need to set default account.");
-    return defaultAccount;
-  }
-
-  private async _sendTransaction(txBody: TransactionBody) {
-    return await this.ain.sendTransaction(txBody);
-  }
-
-  private hasFailedOpResultList(result: txResult): boolean {
-    if (result.result_list) {
-      return Object.values(result.result_list).some(
-        (result: { code: number }) => result.code !== 0
-      );
-    }
-    return result.code !== 0;
-  }
-
-  private handleTxResultWrapper(operation: Function) {
-    return async (args: any) => {
-      const res = await operation(args);
-      const { tx_hash, result } = res;
-      if (this.hasFailedOpResultList(result)) {
-        throw new Error(
-          `Failed to send transaction (${tx_hash}).\n Tx Result: ${JSON.stringify(result)}`
-        );
-      }
-      return tx_hash;
-    }
-  }
-
-  protected sendTransaction = this.handleTxResultWrapper(this._sendTransaction.bind(this));
-}