diff --git a/pom.xml b/pom.xml
index b453c0b..ffad089 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,6 +36,18 @@
             <scope>test</scope>
             <version>3.1.2</version>
         </dependency>
+        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+            <version>3.1.3</version>
+        </dependency>
+        <!-- https://mvnrepository.com/artifact/com.microsoft.sqlserver/mssql-jdbc -->
+        <dependency>
+            <groupId>com.microsoft.sqlserver</groupId>
+            <artifactId>mssql-jdbc</artifactId>
+            <version>12.4.1.jre11</version>
+        </dependency>
     </dependencies>
     <build>
         <plugins>
diff --git a/src/main/java/entities/Categories.java b/src/main/java/entities/Categories.java
new file mode 100644
index 0000000..43bda11
--- /dev/null
+++ b/src/main/java/entities/Categories.java
@@ -0,0 +1,33 @@
+package entities;
+
+public class Categories {
+
+    public enum ExpenseCategory {
+        CREDIT, BUY, BUSINESS, ENTERTAINMENT, RESTAURANTS_AND_CAFE, COMMUNAL_PAYMENTS, SUPERMARKET, MISC;
+
+        public String getEffectiveName() {
+            return Categories.getEffectiveName(this.name());
+        }
+    }
+
+    public enum IncomeCategory {
+        P2P, SALARY, GIFT, CREDIT, MISC;
+
+        public String getEffectiveName() {
+            return Categories.getEffectiveName(this.name());
+        }
+    }
+
+    private static String getEffectiveName(String name) {
+        String[] arr = name.split("_");
+        StringBuilder result = new StringBuilder();
+        for(String entry : arr) {
+            String[] entryArr = entry.split("");
+            StringBuilder builder = new StringBuilder(entryArr[0]);
+            for(int i = 1; i < entry.length(); i++) builder.append(entryArr[i].toLowerCase());
+            result.append(builder).append(" ");
+        }
+        return result.toString();
+    }
+
+}
diff --git a/src/main/java/entities/Expense.java b/src/main/java/entities/Expense.java
new file mode 100644
index 0000000..c6b2c3b
--- /dev/null
+++ b/src/main/java/entities/Expense.java
@@ -0,0 +1,41 @@
+package entities;
+
+public class Expense implements IMoneyTransaction {
+
+    private int userId;
+    private int amount;
+    private Categories.ExpenseCategory category;
+
+    public Expense(int userId, int amount, Categories.ExpenseCategory category) {
+        this.userId = userId;
+        this.amount = amount;
+        this.category = category;
+    }
+
+    @Override
+    public long getUserId() {
+        return userId;
+    }
+
+    public void setUserId(int userId) {
+        this.userId = userId;
+    }
+
+    @Override
+    public int getAmount() {
+        return amount;
+    }
+
+    public void setAmount(int amount) {
+        this.amount = amount;
+    }
+
+    @Override
+    public String getCategory() {
+        return category.getEffectiveName();
+    }
+
+    public void setCategory(Categories.ExpenseCategory category) {
+        this.category = category;
+    }
+}
diff --git a/src/main/java/entities/IMoneyTransaction.java b/src/main/java/entities/IMoneyTransaction.java
new file mode 100644
index 0000000..70b92d5
--- /dev/null
+++ b/src/main/java/entities/IMoneyTransaction.java
@@ -0,0 +1,9 @@
+package entities;
+
+public interface IMoneyTransaction {
+
+    long getUserId();
+    int getAmount();
+    String getCategory();
+
+}
diff --git a/src/main/java/entities/Income.java b/src/main/java/entities/Income.java
new file mode 100644
index 0000000..31b5d67
--- /dev/null
+++ b/src/main/java/entities/Income.java
@@ -0,0 +1,41 @@
+package entities;
+
+public class Income implements IMoneyTransaction {
+
+    private long userId;
+    private int amount;
+    private Categories.IncomeCategory category;
+
+    public Income(long userId, int amount, Categories.IncomeCategory category) {
+        this.userId = userId;
+        this.amount = amount;
+        this.category = category;
+    }
+
+    @Override
+    public long getUserId() {
+        return userId;
+    }
+
+    @Override
+    public int getAmount() {
+        return amount;
+    }
+
+    @Override
+    public String getCategory() {
+        return category.getEffectiveName();
+    }
+
+    public void setUserId(long userId) {
+        this.userId = userId;
+    }
+
+    public void setAmount(int amount) {
+        this.amount = amount;
+    }
+
+    public void setCategory(Categories.IncomeCategory category) {
+        this.category = category;
+    }
+}
diff --git a/src/main/java/entities/Role.java b/src/main/java/entities/Role.java
new file mode 100644
index 0000000..258e49e
--- /dev/null
+++ b/src/main/java/entities/Role.java
@@ -0,0 +1,7 @@
+package entities;
+
+public enum Role {
+
+    UNREGISTERED, REGISTERED, ADMIN;
+
+}
diff --git a/src/main/java/entities/User.java b/src/main/java/entities/User.java
new file mode 100644
index 0000000..37f571a
--- /dev/null
+++ b/src/main/java/entities/User.java
@@ -0,0 +1,88 @@
+package entities;
+
+import java.util.List;
+
+public class User {
+    private long id;
+    private String name, email, login, password;
+    private Role role;
+    private List<Expense> expenses;
+    private List<Income> incomes;
+
+    public User(long id, String name, String email, String login, String password, Role role, List<Expense> expenses, List<Income> incomes) {
+        this.id = id;
+        this.name = name;
+        this.email = email;
+        this.login = login;
+        this.password = password;
+        this.role = role;
+        this.expenses = expenses;
+        this.incomes = incomes;
+    }
+
+    public User() {}
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getLogin() {
+        return login;
+    }
+
+    public void setLogin(String login) {
+        this.login = login;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public Role getRole() {
+        return role;
+    }
+
+    public void setRole(Role role) {
+        this.role = role;
+    }
+
+    public List<Expense> getExpenses() {
+        return expenses;
+    }
+
+    public void setExpenses(List<Expense> expenses) {
+        this.expenses = expenses;
+    }
+
+    public List<Income> getIncomes() {
+        return incomes;
+    }
+
+    public void setIncomes(List<Income> incomes) {
+        this.incomes = incomes;
+    }
+}