diff --git a/src/createServer.js b/src/createServer.js
index 5b405372..fab67451 100644
--- a/src/createServer.js
+++ b/src/createServer.js
@@ -1,11 +1,248 @@
 'use strict';
 
-// const express = require('express');
+const express = require('express');
+const cors = require('cors');
 
 function createServer() {
-  // Use express to create a server
-  // Add a routes to the server
-  // Return the server (express app)
+  const app = express();
+
+  app.use(cors());
+  app.use(express.json());
+
+  const users = [];
+  const expenses = [];
+
+  let nextUserId = 1;
+  let nextExpenseId = 1;
+
+  app.post('/users', (req, res) => {
+    const { name } = req.body;
+
+    if (!name) {
+      res.sendStatus(400);
+
+      return;
+    }
+
+    const user = {
+      id: nextUserId,
+      name,
+    };
+
+    nextUserId += 1;
+    users.push(user);
+
+    res.status(201).json(user);
+  });
+
+  app.get('/users', (req, res) => {
+    res.json(users);
+  });
+
+  app.get('/users/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const user = users.find((currentUser) => currentUser.id === id);
+
+    if (!user) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    res.json(user);
+  });
+
+  app.patch('/users/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const user = users.find((currentUser) => currentUser.id === id);
+
+    if (!user) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    const { name } = req.body;
+
+    if (!name) {
+      res.sendStatus(400);
+
+      return;
+    }
+
+    user.name = name;
+
+    res.json(user);
+  });
+
+  app.delete('/users/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const userIndex = users.findIndex((currentUser) => currentUser.id === id);
+
+    if (userIndex === -1) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    users.splice(userIndex, 1);
+
+    res.sendStatus(204);
+  });
+
+  app.post('/expenses', (req, res) => {
+    const { userId, spentAt, title, amount, category, note } = req.body;
+
+    if (
+      userId === undefined ||
+      !spentAt ||
+      !title ||
+      amount === undefined ||
+      !category
+    ) {
+      res.sendStatus(400);
+
+      return;
+    }
+
+    const user = users.find((currentUser) => currentUser.id === userId);
+
+    if (!user) {
+      res.sendStatus(400);
+
+      return;
+    }
+
+    const expense = {
+      id: nextExpenseId,
+      userId,
+      spentAt,
+      title,
+      amount,
+      category,
+      note,
+    };
+
+    nextExpenseId += 1;
+    expenses.push(expense);
+
+    res.status(201).json(expense);
+  });
+
+  app.get('/expenses', (req, res) => {
+    const { userId, from, to, categories } = req.query;
+
+    let filteredExpenses = [...expenses];
+
+    if (userId) {
+      filteredExpenses = filteredExpenses.filter(
+        (expense) => expense.userId === Number(userId),
+      );
+    }
+
+    if (from) {
+      filteredExpenses = filteredExpenses.filter(
+        (expense) => new Date(expense.spentAt) >= new Date(from),
+      );
+    }
+
+    if (to) {
+      filteredExpenses = filteredExpenses.filter(
+        (expense) => new Date(expense.spentAt) <= new Date(to),
+      );
+    }
+
+    if (categories) {
+      const categoryList = []
+        .concat(categories)
+        .flatMap((category) => category.split(','));
+
+      filteredExpenses = filteredExpenses.filter((expense) => {
+        return categoryList.includes(expense.category);
+      });
+    }
+
+    res.json(filteredExpenses);
+  });
+
+  app.get('/expenses/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const expense = expenses.find((currentExpense) => currentExpense.id === id);
+
+    if (!expense) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    res.json(expense);
+  });
+
+  app.patch('/expenses/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const expense = expenses.find((currentExpense) => currentExpense.id === id);
+
+    if (!expense) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    const { userId, spentAt, title, amount, category, note } = req.body;
+
+    if (userId !== undefined) {
+      const user = users.find((currentUser) => currentUser.id === userId);
+
+      if (!user) {
+        res.sendStatus(400);
+
+        return;
+      }
+
+      expense.userId = userId;
+    }
+
+    if (spentAt !== undefined) {
+      expense.spentAt = spentAt;
+    }
+
+    if (title !== undefined) {
+      expense.title = title;
+    }
+
+    if (amount !== undefined) {
+      expense.amount = amount;
+    }
+
+    if (category !== undefined) {
+      expense.category = category;
+    }
+
+    if (note !== undefined) {
+      expense.note = note;
+    }
+
+    res.json(expense);
+  });
+
+  app.delete('/expenses/:id', (req, res) => {
+    const id = Number(req.params.id);
+    const expenseIndex = expenses.findIndex(
+      (currentExpense) => currentExpense.id === id,
+    );
+
+    if (expenseIndex === -1) {
+      res.sendStatus(404);
+
+      return;
+    }
+
+    expenses.splice(expenseIndex, 1);
+
+    res.sendStatus(204);
+  });
+
+  return app;
 }
 
 module.exports = {