diff --git a/demo/src/index.ts b/demo/src/index.ts
index 9d9e281..764d511 100644
--- a/demo/src/index.ts
+++ b/demo/src/index.ts
@@ -36,8 +36,9 @@ const server = new Server({
   assetsRoot: Config.publicDir
 });
 
-routerMap.get('/', async (ctx, next) => {
-  ctx.body = '';
+routerMap.get('/test-multi', async (ctx, next) => {
+  ctx.body = 'hi~';
+  next && await next(ctx);
   next && await next(ctx);
 });
 
diff --git a/lerna.json b/lerna.json
index 6cb6834..2c30a7e 100644
--- a/lerna.json
+++ b/lerna.json
@@ -8,5 +8,6 @@
     "ignoreChanges": ["ignored-file", "*.md"],
     "message": "chore(release): publish",
     "registry": "https://registry.npmjs.org"
-  }
+  },
+  "npmClient": "yarn"
 }
diff --git a/packages/auf-typing/package.json b/packages/auf-typing/package.json
index 7bb9cef..9743415 100644
--- a/packages/auf-typing/package.json
+++ b/packages/auf-typing/package.json
@@ -34,5 +34,8 @@
     "rimraf": "^3.0.2",
     "typescript": "^4.6.2"
   },
-  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b"
+  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b",
+  "resolutions": {
+    "@types/node": "15.6.2"
+  }
 }
diff --git a/packages/auf-typing/src/index.ts b/packages/auf-typing/src/index.ts
index ec5e43f..872bd06 100644
--- a/packages/auf-typing/src/index.ts
+++ b/packages/auf-typing/src/index.ts
@@ -9,12 +9,18 @@ export interface IServerOptions {
   errorHandler?: (e: Error) => void;
 }
 
+export type ContextExtendInfoType = {
+  visMap: WeakSet<IMiddleWare>;
+  handled: boolean;
+  [key: string]: any;
+}
+
 export interface IContext {
   req: http.IncomingMessage;
   res: http.ServerResponse;
   serverOptions: IServerOptions;
   body: string | Readable | Record<string, any>;
-  extendInfo: Record<string, any>;
+  extendInfo: ContextExtendInfoType;
   get reqBody(): Record<string, any>;
   get query(): Record<string, string>;
   get params(): Record<string, string>; 
diff --git a/packages/auf/src/index.ts b/packages/auf/src/index.ts
index 16c5dec..839006a 100644
--- a/packages/auf/src/index.ts
+++ b/packages/auf/src/index.ts
@@ -1,12 +1,4 @@
-export {
-  Server,
-  ClusterServer,
-  Router,
-  RouterMapFactory,
-  IClusterServerOptions,
-  CommonError,
-  isCommonError
-} from '@vergiss/auf-core';
+export * from '@vergiss/auf-core';
 
 export * as Middlewares from '@vergiss/auf-middlewares';
 export { IContext, IMiddleWare, IServerOptions } from '@vergiss/auf-typing';
diff --git a/packages/core/package.json b/packages/core/package.json
index 8b98530..73283fc 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -39,5 +39,8 @@
   "dependencies": {
     "@vergiss/auf-helpers": "^0.3.0"
   },
-  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b"
+  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b",
+  "resolutions": {
+    "@types/node": "15.6.2"
+  }
 }
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 7f37b59..6a76b24 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,13 +1,4 @@
-import { ClusterServer, Server, IClusterServerOptions } from './server';
-import { Router, RouterMapFactory } from './router';
+export { ClusterServer, Server, IClusterServerOptions } from './server';
+export { Router, RouterMapFactory } from './router';
 
-export { CommonError, isCommonError } from '@vergiss/auf-helpers';
-export {
-  Server,
-  ClusterServer,
-  Router,
-  RouterMapFactory,
-
-  // declarations
-  IClusterServerOptions,
-}
\ No newline at end of file
+export { CommonError, isCommonError, throwCommonError } from '@vergiss/auf-helpers';
\ No newline at end of file
diff --git a/packages/core/src/router/prefix-tree/index.ts b/packages/core/src/router/prefix-tree/index.ts
index 055ad61..35aa1a5 100644
--- a/packages/core/src/router/prefix-tree/index.ts
+++ b/packages/core/src/router/prefix-tree/index.ts
@@ -1,5 +1,5 @@
 
-import { CommonError } from '@vergiss/auf-helpers';
+import { throwCommonError } from '@vergiss/auf-helpers';
 import {
   NTreeNode,
   RouterRegExpLeafNode,
@@ -78,7 +78,7 @@ class NTree<T> implements IRouterTree<T> {
     const matchedRegExpNodes = regExpNodes.filter(node => node.exp.test(url));
 
     if (matchedRegExpNodes.length === 0) {
-      throw new CommonError({
+      throwCommonError({
         message: 'Route not defined',
         statusCode: 404,
         statusMessage: 'Not Found'
@@ -143,11 +143,11 @@ class NTree<T> implements IRouterTree<T> {
       const leafNode = p.quickMap.get(LEAF_SIGN);
 
       if (leafNode == null) {
-        throw new CommonError({
+        throwCommonError({
           message: 'Handler not defined',
           statusCode: 500,
           statusMessage: 'Handler Not Found'
-        });
+        })
       }
 
       res = (leafNode as RouterTreeLeafNode<T>).value;
diff --git a/packages/core/src/server/base-server.ts b/packages/core/src/server/base-server.ts
index ad79ed4..09a88e1 100644
--- a/packages/core/src/server/base-server.ts
+++ b/packages/core/src/server/base-server.ts
@@ -13,10 +13,10 @@ class BaseServer implements IBaseServer {
     const { port } = this.options;
     http.createServer(async (_, res) => {
       const ctx = new Context(_, res, this.options);
-      if (handleContext) {
-        await handleContext(ctx);
-      }
       try {
+        if (handleContext) {
+          await handleContext(ctx);
+        }
         if (ctx.body == null) {
           res.end('');
           return;
diff --git a/packages/core/src/server/context.ts b/packages/core/src/server/context.ts
index c76cee4..6fd71be 100644
--- a/packages/core/src/server/context.ts
+++ b/packages/core/src/server/context.ts
@@ -1,18 +1,21 @@
 import * as http from 'http';
-import { IContext, IServerOptions } from '@vergiss/auf-typing';
+import { IContext, IServerOptions, ContextExtendInfoType } from '@vergiss/auf-typing';
 
 class Context implements IContext {
   public res: http.ServerResponse;
   public req: http.IncomingMessage;
   public serverOptions: IServerOptions;
-  public extendInfo: any;
+  public extendInfo: ContextExtendInfoType;
   private _body: any;
   constructor (req: http.IncomingMessage, res: http.ServerResponse, serverOptions: IServerOptions) {
     this.res = res;
     this.req = req;
     this.serverOptions = serverOptions;
     this._body = {} as any;
-    this.extendInfo = {} as any;
+    this.extendInfo = {
+      visMap: new WeakSet(),
+      handled: false
+    };
   }
 
   get body() {
diff --git a/packages/core/src/server/interface.ts b/packages/core/src/server/interface.ts
index 90598b6..714b556 100644
--- a/packages/core/src/server/interface.ts
+++ b/packages/core/src/server/interface.ts
@@ -16,6 +16,6 @@ export interface IClusterServerOptions extends IServerOptions {
 }
 
 export interface IMiddlewareAbility {
-  next(ctx: IContext): Promise<unknown>;
+  next(ctx: IContext): void;
   applyMiddleware(middlewares: IMiddleWare[]): void 
 }
\ No newline at end of file
diff --git a/packages/core/src/server/middlewares.ts b/packages/core/src/server/middlewares.ts
index 3540fc5..be9a6e5 100644
--- a/packages/core/src/server/middlewares.ts
+++ b/packages/core/src/server/middlewares.ts
@@ -2,31 +2,54 @@ import { compose } from '@vergiss/auf-helpers';
 import { IContext, IMiddleWare } from '@vergiss/auf-typing';
 import { IMiddlewareAbility } from './interface';
 
+/**
+ * Check if a middleware is called multiple times. It has side effect.
+ * @param fn The middleware function
+ * @param ctx Context object
+ */
+function checkIfMultipleVisited (fn: IMiddleWare, ctx: IContext) {
+  if (ctx.extendInfo.visMap.has(fn)) {
+    throw new Error('The "next" method can\'t be called multiple times.');
+  }
+  ctx.extendInfo.visMap.add(fn);
+}
+
+/**
+ * Returns a resolved promise as the middlewares chain's tail.
+ * @param ctx Context object
+ */
+function wrapResolvedPromise (ctx: IContext) {
+  checkIfMultipleVisited(wrapResolvedPromise, ctx);
+  return Promise.resolve();
+}
+
 class Middlewares {
-  public middlewares: Function[];
-  constructor (middlewares: Function[]) {
+  private middlewares: Array<IMiddleWare>;
+  private wrappedMiddlewares: Array<(fn?: IMiddleWare) => void>;
+  constructor (middlewares: IMiddleWare[]) {
     this.middlewares = middlewares
   }
 
-  applyMiddlewares(): (ctx: IContext) => Promise<unknown> {
-    this.middlewares = this.middlewares.map(fn => {
-      return function (next = (() => Promise.resolve())) {
+  getMiddlewareChain(): (ctx: IContext) => void {
+    this.wrappedMiddlewares = this.middlewares.map(fn => {
+      return function (next = wrapResolvedPromise) {
         return async function (ctx: IContext) {
+          checkIfMultipleVisited(fn, ctx);
           await fn(ctx, next);
         }
       }
-    })
-    const [lastActionGenerator, ...restActionGenerators] = this.middlewares.reverse();
+    });
+    const [lastActionGenerator, ...restActionGenerators] = this.wrappedMiddlewares.reverse();
 
     return compose(restActionGenerators)(lastActionGenerator());
   }
 }
 
 export class MiddlewaresAbility implements IMiddlewareAbility {
-  next: (ctx: IContext) => Promise<unknown>;
+  next: (ctx: IContext) => void;
   private middleware: Middlewares;
   applyMiddleware(middlewares: IMiddleWare[]): void {
     this.middleware = new Middlewares(middlewares);
-    this.next = this.middleware.applyMiddlewares();
+    this.next = this.middleware.getMiddlewareChain();
   }
 }
\ No newline at end of file
diff --git a/packages/helpers/package.json b/packages/helpers/package.json
index d866a35..32005ae 100644
--- a/packages/helpers/package.json
+++ b/packages/helpers/package.json
@@ -37,5 +37,8 @@
     "ts-node": "^10.7.0",
     "typescript": "^4.3.2"
   },
-  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b"
+  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b",
+  "resolutions": {
+    "@types/node": "15.6.2"
+  }
 }
diff --git a/packages/helpers/src/error.ts b/packages/helpers/src/error.ts
index 97483d0..ef14a9e 100644
--- a/packages/helpers/src/error.ts
+++ b/packages/helpers/src/error.ts
@@ -17,10 +17,15 @@ class CommonError extends Error {
   }
 }
 
+function throwCommonError(options: ICommonErrorOptions): never {
+  throw new CommonError(options);
+}
+
 function isCommonError (value: any): value is CommonError {
   return value.type === commonErrorSymbol;
 }
 export {
   CommonError,
-  isCommonError
+  isCommonError,
+  throwCommonError
 }
\ No newline at end of file
diff --git a/packages/helpers/src/index.ts b/packages/helpers/src/index.ts
index eaee46d..18bcc41 100644
--- a/packages/helpers/src/index.ts
+++ b/packages/helpers/src/index.ts
@@ -1,7 +1,7 @@
-export { compose, composePromise } from './functional';
-export { checkMimeTypes } from './mime-type';
-export { uuid } from './tools';
-export { getMD5 } from './md5';
-export { LRUCache } from './lru-cache';
-export { CommonError, isCommonError } from './error';
+export * from './functional';
+export * from './mime-type';
+export * from './tools';
+export * from './md5';
+export * from './lru-cache';
+export * from './error';
 
diff --git a/packages/middlewares/package.json b/packages/middlewares/package.json
index a8927d2..7959fde 100644
--- a/packages/middlewares/package.json
+++ b/packages/middlewares/package.json
@@ -38,5 +38,8 @@
     "@vergiss/auf-helpers": "^0.3.0",
     "@vergiss/auf-template-engine": "^0.4.0"
   },
-  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b"
+  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b",
+  "resolutions": {
+    "@types/node": "15.6.2"
+  }
 }
diff --git a/packages/template-engine/package.json b/packages/template-engine/package.json
index f430cd8..365c31e 100644
--- a/packages/template-engine/package.json
+++ b/packages/template-engine/package.json
@@ -25,5 +25,8 @@
     "ts-node": "^10.7.0",
     "typescript": "^4.3.2"
   },
-  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b"
+  "gitHead": "3f74b38e9dc2a875da3de1a32d4c045acb975d7b",
+  "resolutions": {
+    "@types/node": "15.6.2"
+  }
 }