diff --git a/catDataMocking/src/app.ts b/catDataMocking/src/app.ts
index 700a538..3f06e0a 100644
--- a/catDataMocking/src/app.ts
+++ b/catDataMocking/src/app.ts
@@ -3,29 +3,53 @@ import * as cors from "cors";
 
 import catsRouter from "./cats/cats.route";
 
-const app: express.Express = express();
 const port: number = 8000;
-
-app.use(cors());
-
-// * Logging Middleware
-app.use((req, res, next) => {
-  console.log(req.rawHeaders[1]);
-  next();
-});
-
-// * json middleware
-app.use(express.json());
-
-app.use(catsRouter);
-
-// * 404 middleware
-app.use((req, res, next) => {
-  console.log(req.rawHeaders[1]);
-  console.log("This is 404 middleware");
-  res.send({ error: "404 not found error" });
-});
-
-app.listen(port, () => {
-  console.log(`server is on ${port}`);
-});
+class Server {
+  public app: express.Application;
+
+  constructor() {
+    const app: express.Application = express();
+    this.app = app;
+  }
+
+  private setRoute() {
+    // * router
+    this.app.use(catsRouter);
+  }
+
+  private setMiddleware() {
+    this.app.use(cors());
+
+    // * Logging Middleware
+    this.app.use((req, res, next) => {
+      console.log(req.rawHeaders[1]);
+      next();
+    });
+
+    // * json middleware
+    this.app.use(express.json());
+
+    this.setRoute();
+
+    // * 404 middleware
+    this.app.use((req, res, next) => {
+      console.log(req.rawHeaders[1]);
+      console.log("This is 404 middleware");
+      res.send({ error: "404 not found error" });
+    });
+  }
+
+  public listen() {
+    this.setMiddleware();
+    this.app.listen(port, () => {
+      console.log(`server is on ${port}`);
+    });
+  }
+}
+
+function init() {
+  const server = new Server();
+  server.listen();
+}
+
+init();
diff --git a/catDataMocking/src/cats/cats.route.ts b/catDataMocking/src/cats/cats.route.ts
index 054569f..19e4d4b 100644
--- a/catDataMocking/src/cats/cats.route.ts
+++ b/catDataMocking/src/cats/cats.route.ts
@@ -1,124 +1,21 @@
 import { Router } from "express";
 import { CatType, Cat } from "./cats.model";
+import {
+  createCat,
+  deleteCat,
+  readAllCat,
+  readCat,
+  updateCat,
+  updatePartialCat,
+} from "./cats.service";
 
 const router = Router();
 
-// * C
-router.post("/cats", (req, res) => {
-  try {
-    const data = req.body;
-    Cat.push(data);
-    res.status(200).send({
-      success: true,
-      data: { data },
-    });
-  } catch (error) {}
-});
-
-// * R
-router.get("/cats", (req, res) => {
-  try {
-    const cats = Cat;
-    res.status(200).send({
-      success: true,
-      data: { cats },
-    });
-  } catch (error) {
-    res.status(400).send({
-      success: false,
-      error: error.message,
-    });
-  }
-});
-
-router.get("/cats/:id", (req, res) => {
-  try {
-    const params = req.params;
-    const cats = Cat.find((cat) => {
-      return cat.id === params.id;
-    });
-    if (!cats) throw new Error("no matched data");
-    res.status(200).send({
-      success: true,
-      data: { cats },
-    });
-  } catch (error) {
-    res.status(400).send({
-      success: false,
-      error: error.message,
-    });
-  }
-});
-
-// * U
-router.put("/cats/:id", (req, res) => {
-  try {
-    const params = req.params;
-    const body = req.body;
-    let result;
-    const index = Cat.findIndex((cat) => cat.id === params.id);
-    if (index !== -1) {
-      const tempId = params.id;
-      const newCat = { ...body, id: tempId };
-      Cat[index] = newCat;
-      result = newCat;
-    }
-    res.status(200).send({
-      success: true,
-      data: { cat: result },
-    });
-  } catch (error) {
-    res.status(400).send({
-      success: false,
-      error: error.message,
-    });
-  }
-});
-
-router.patch("/cats/:id", (req, res) => {
-  try {
-    const params = req.params;
-    const body = req.body;
-    let result;
-    const index = Cat.findIndex((cat) => cat.id === params.id);
-    if (index !== -1) {
-      const tempId = params.id;
-      const newCat = { ...Cat[index], ...body, id: tempId };
-      Cat[index] = newCat;
-      result = newCat;
-    }
-    res.status(200).send({
-      success: true,
-      data: { cat: result },
-    });
-  } catch (error) {
-    res.status(400).send({
-      success: false,
-      error: error.message,
-    });
-  }
-});
-
-// * D
-router.delete("/cats/:id", (req, res) => {
-  try {
-    const params = req.params;
-    const body = req.body;
-    let result;
-    const index = Cat.findIndex((cat) => cat.id === params.id);
-    if (index !== -1) {
-      Cat.splice(index, 1);
-    }
-    res.status(200).send({
-      success: true,
-      data: { cat: result },
-    });
-  } catch (error) {
-    res.status(400).send({
-      success: false,
-      error: error.message,
-    });
-  }
-});
+router.post("/cats", createCat);
+router.get("/cats", readAllCat);
+router.get("/cats/:id", readCat);
+router.put("/cats/:id", updateCat);
+router.patch("/cats/:id", updatePartialCat);
+router.delete("/cats/:id", deleteCat);
 
 export default router;
diff --git a/catDataMocking/src/cats/cats.service.ts b/catDataMocking/src/cats/cats.service.ts
new file mode 100644
index 0000000..ff0b84b
--- /dev/null
+++ b/catDataMocking/src/cats/cats.service.ts
@@ -0,0 +1,120 @@
+import { Request, Response } from "express";
+import { CatType, Cat } from "./cats.model";
+
+// * C
+export const createCat = (req: Request, res: Response) => {
+  try {
+    const data = req.body;
+    Cat.push(data);
+    res.status(200).send({
+      success: true,
+      data: { data },
+    });
+  } catch (error) {}
+};
+
+// * R
+export const readAllCat = (req: Request, res: Response) => {
+  try {
+    const cats = Cat;
+    res.status(200).send({
+      success: true,
+      data: { cats },
+    });
+  } catch (error) {
+    res.status(400).send({
+      success: false,
+      error: error.message,
+    });
+  }
+};
+
+export const readCat = (req: Request, res: Response) => {
+  try {
+    const params = req.params;
+    const cats = Cat.find((cat) => {
+      return cat.id === params.id;
+    });
+    if (!cats) throw new Error("no matched data");
+    res.status(200).send({
+      success: true,
+      data: { cats },
+    });
+  } catch (error) {
+    res.status(400).send({
+      success: false,
+      error: error.message,
+    });
+  }
+};
+
+// * U
+export const updateCat = (req: Request, res: Response) => {
+  try {
+    const params = req.params;
+    const body = req.body;
+    let result;
+    const index = Cat.findIndex((cat) => cat.id === params.id);
+    if (index !== -1) {
+      const tempId = params.id;
+      const newCat = { ...body, id: tempId };
+      Cat[index] = newCat;
+      result = newCat;
+    }
+    res.status(200).send({
+      success: true,
+      data: { cat: result },
+    });
+  } catch (error) {
+    res.status(400).send({
+      success: false,
+      error: error.message,
+    });
+  }
+};
+
+export const updatePartialCat = (req: Request, res: Response) => {
+  try {
+    const params = req.params;
+    const body = req.body;
+    let result;
+    const index = Cat.findIndex((cat) => cat.id === params.id);
+    if (index !== -1) {
+      const tempId = params.id;
+      const newCat = { ...Cat[index], ...body, id: tempId };
+      Cat[index] = newCat;
+      result = newCat;
+    }
+    res.status(200).send({
+      success: true,
+      data: { cat: result },
+    });
+  } catch (error) {
+    res.status(400).send({
+      success: false,
+      error: error.message,
+    });
+  }
+};
+
+// * D
+export const deleteCat = (req: Request, res: Response) => {
+  try {
+    const params = req.params;
+    const body = req.body;
+    let result;
+    const index = Cat.findIndex((cat) => cat.id === params.id);
+    if (index !== -1) {
+      Cat.splice(index, 1);
+    }
+    res.status(200).send({
+      success: true,
+      data: { cat: result },
+    });
+  } catch (error) {
+    res.status(400).send({
+      success: false,
+      error: error.message,
+    });
+  }
+};