diff --git a/pom.xml b/pom.xml
index 6d1fee4..d7bdb34 100644
--- a/pom.xml
+++ b/pom.xml
@@ -15,6 +15,7 @@
     <description>banking-service</description>
     <properties>
         <java.version>17</java.version>
+        <modelmapper.version>3.1.1</modelmapper.version>
     </properties>
     <dependencies>
         <dependency>
@@ -29,6 +30,15 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.modelmapper</groupId>
+            <artifactId>modelmapper</artifactId>
+            <version>${modelmapper.version}</version>
+        </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>
diff --git a/src/main/java/net/kapcake/bankingservice/domain/Balance.java b/src/main/java/net/kapcake/bankingservice/domain/Balance.java
deleted file mode 100644
index 2dd84a8..0000000
--- a/src/main/java/net/kapcake/bankingservice/domain/Balance.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package net.kapcake.bankingservice.domain;
-
-import jakarta.persistence.*;
-import lombok.Data;
-
-@Entity
-@Data
-public class Balance {
-    @Id
-    @GeneratedValue
-    private Long id;
-    private Long amount;
-    private String currency;
-    @Enumerated(EnumType.STRING)
-    private BalanceType type;
-}
diff --git a/src/main/java/net/kapcake/bankingservice/domain/PaymentStatus.java b/src/main/java/net/kapcake/bankingservice/domain/PaymentStatus.java
deleted file mode 100644
index e74f882..0000000
--- a/src/main/java/net/kapcake/bankingservice/domain/PaymentStatus.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package net.kapcake.bankingservice.domain;
-
-public enum PaymentStatus {
-    EXECUTED
-}
diff --git a/src/main/java/net/kapcake/bankingservice/domain/AccountStatus.java b/src/main/java/net/kapcake/bankingservice/model/domain/AccountStatus.java
similarity index 53%
rename from src/main/java/net/kapcake/bankingservice/domain/AccountStatus.java
rename to src/main/java/net/kapcake/bankingservice/model/domain/AccountStatus.java
index 03bb411..31edd55 100644
--- a/src/main/java/net/kapcake/bankingservice/domain/AccountStatus.java
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/AccountStatus.java
@@ -1,4 +1,4 @@
-package net.kapcake.bankingservice.domain;
+package net.kapcake.bankingservice.model.domain;
 
 public enum AccountStatus {
     ENABLED,
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/BalanceDTO.java b/src/main/java/net/kapcake/bankingservice/model/domain/BalanceDTO.java
new file mode 100644
index 0000000..7b5af82
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/BalanceDTO.java
@@ -0,0 +1,19 @@
+package net.kapcake.bankingservice.model.domain;
+
+import jakarta.validation.constraints.DecimalMin;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+import java.math.BigDecimal;
+
+@Data
+public class BalanceDTO {
+    private Long id;
+    @NotNull
+    @DecimalMin(value = "0", inclusive = false)
+    private BigDecimal amount;
+    @NotNull
+    private Currency currency;
+    @NotNull
+    private BalanceType type;
+}
diff --git a/src/main/java/net/kapcake/bankingservice/domain/BalanceType.java b/src/main/java/net/kapcake/bankingservice/model/domain/BalanceType.java
similarity index 54%
rename from src/main/java/net/kapcake/bankingservice/domain/BalanceType.java
rename to src/main/java/net/kapcake/bankingservice/model/domain/BalanceType.java
index a84fa45..cf2d8f6 100644
--- a/src/main/java/net/kapcake/bankingservice/domain/BalanceType.java
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/BalanceType.java
@@ -1,4 +1,4 @@
-package net.kapcake.bankingservice.domain;
+package net.kapcake.bankingservice.model.domain;
 
 public enum BalanceType {
     END_OF_DAY,
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/BankAccountDTO.java b/src/main/java/net/kapcake/bankingservice/model/domain/BankAccountDTO.java
new file mode 100644
index 0000000..ed8f3d7
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/BankAccountDTO.java
@@ -0,0 +1,25 @@
+package net.kapcake.bankingservice.model.domain;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import jakarta.validation.constraints.NotBlank;
+import jakarta.validation.constraints.NotEmpty;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+import java.util.List;
+
+@Data
+public class BankAccountDTO {
+    private Long id;
+    @NotBlank
+    private String accountNumber;
+    @NotEmpty
+    @JsonIgnore
+    private List<UserDTO> users;
+    @NotBlank
+    private String accountName;
+    @NotEmpty
+    private List<BalanceDTO> balances;
+    @NotNull
+    private AccountStatus status;
+}
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/Currency.java b/src/main/java/net/kapcake/bankingservice/model/domain/Currency.java
new file mode 100644
index 0000000..9415d9d
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/Currency.java
@@ -0,0 +1,7 @@
+package net.kapcake.bankingservice.model.domain;
+
+public enum Currency {
+    EUR,
+    USD,
+    GBP
+}
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/PaymentDTO.java b/src/main/java/net/kapcake/bankingservice/model/domain/PaymentDTO.java
new file mode 100644
index 0000000..56cc1c1
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/PaymentDTO.java
@@ -0,0 +1,27 @@
+package net.kapcake.bankingservice.model.domain;
+
+import jakarta.validation.constraints.DecimalMin;
+import jakarta.validation.constraints.NotNull;
+import lombok.Data;
+
+import java.math.BigDecimal;
+import java.util.Date;
+
+@Data
+public class PaymentDTO {
+    private Long id;
+    @NotNull
+    @DecimalMin(value = "0", inclusive = false)
+    private BigDecimal amount;
+    @NotNull
+    private Currency currency;
+    @NotNull
+    private Long giverAccount;
+    @NotNull
+    private String beneficiaryAccountNumber;
+    @NotNull
+    private String beneficiaryName;
+    private String communication;
+    private Date creationDate;
+    private PaymentStatus status;
+}
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/PaymentStatus.java b/src/main/java/net/kapcake/bankingservice/model/domain/PaymentStatus.java
new file mode 100644
index 0000000..f9ac549
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/PaymentStatus.java
@@ -0,0 +1,5 @@
+package net.kapcake.bankingservice.model.domain;
+
+public enum PaymentStatus {
+    EXECUTED
+}
diff --git a/src/main/java/net/kapcake/bankingservice/model/domain/UserDTO.java b/src/main/java/net/kapcake/bankingservice/model/domain/UserDTO.java
new file mode 100644
index 0000000..29b0e9a
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/domain/UserDTO.java
@@ -0,0 +1,16 @@
+package net.kapcake.bankingservice.model.domain;
+
+import jakarta.validation.constraints.NotEmpty;
+import lombok.Data;
+
+@Data
+public class UserDTO {
+    private Long id;
+    @NotEmpty
+    private String username;
+    private String street;
+    private Integer number;
+    private String numberExtension;
+    private Integer postalCode;
+    private String country;
+}
diff --git a/src/main/java/net/kapcake/bankingservice/model/entities/Balance.java b/src/main/java/net/kapcake/bankingservice/model/entities/Balance.java
new file mode 100644
index 0000000..f98e736
--- /dev/null
+++ b/src/main/java/net/kapcake/bankingservice/model/entities/Balance.java
@@ -0,0 +1,23 @@
+package net.kapcake.bankingservice.model.entities;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.Setter;
+import net.kapcake.bankingservice.model.domain.BalanceType;
+import net.kapcake.bankingservice.model.domain.Currency;
+
+import java.math.BigDecimal;
+
+@Entity
+@Getter
+@Setter
+public class Balance {
+    @Id
+    @GeneratedValue
+    private Long id;
+    private BigDecimal amount;
+    @Enumerated(EnumType.STRING)
+    private Currency currency;
+    @Enumerated(EnumType.STRING)
+    private BalanceType type;
+}
diff --git a/src/main/java/net/kapcake/bankingservice/domain/BankAccount.java b/src/main/java/net/kapcake/bankingservice/model/entities/BankAccount.java
similarity index 54%
rename from src/main/java/net/kapcake/bankingservice/domain/BankAccount.java
rename to src/main/java/net/kapcake/bankingservice/model/entities/BankAccount.java
index d1893ee..5f756f4 100644
--- a/src/main/java/net/kapcake/bankingservice/domain/BankAccount.java
+++ b/src/main/java/net/kapcake/bankingservice/model/entities/BankAccount.java
@@ -1,21 +1,26 @@
-package net.kapcake.bankingservice.domain;
+package net.kapcake.bankingservice.model.entities;
 
 import jakarta.persistence.*;
-import lombok.Data;
+import lombok.Getter;
+import lombok.Setter;
+import net.kapcake.bankingservice.model.domain.AccountStatus;
 
 import java.util.List;
 
 @Entity
-@Data
+@Getter
+@Setter
 public class BankAccount {
     @Id
     @GeneratedValue
     private Long id;
-
     @Column(nullable = false)
     private String accountNumber;
-
     @ManyToMany
+    @JoinTable(
+            joinColumns = {@JoinColumn(name = "BANK_ACCOUNT_ID", nullable = false)},
+            inverseJoinColumns = {@JoinColumn(name = "USER_ID", nullable = false)}
+    )
     private List<User> users;
     @Column(nullable = false)
     private String accountName;
diff --git a/src/main/java/net/kapcake/bankingservice/domain/Payment.java b/src/main/java/net/kapcake/bankingservice/model/entities/Payment.java
similarity index 62%
rename from src/main/java/net/kapcake/bankingservice/domain/Payment.java
rename to src/main/java/net/kapcake/bankingservice/model/entities/Payment.java
index 7c6f25a..b4f25d3 100644
--- a/src/main/java/net/kapcake/bankingservice/domain/Payment.java
+++ b/src/main/java/net/kapcake/bankingservice/model/entities/Payment.java
@@ -1,24 +1,30 @@
-package net.kapcake.bankingservice.domain;
+package net.kapcake.bankingservice.model.entities;
 
 import jakarta.persistence.*;
-import lombok.Data;
+import lombok.Getter;
+import lombok.Setter;
+import net.kapcake.bankingservice.model.domain.Currency;
+import net.kapcake.bankingservice.model.domain.PaymentStatus;
 import org.hibernate.annotations.CreationTimestamp;
 
+import java.math.BigDecimal;
 import java.util.Date;
 
 @Entity
-@Data
+@Getter
+@Setter
 public class Payment {
     @Id
     @GeneratedValue
     private Long id;
     @Column(nullable = false)
-    private Long amount;
+    private BigDecimal amount;
     @Column(nullable = false)
-    private String currency;
+    @Enumerated(EnumType.STRING)
+    private Currency currency;
     @ManyToOne
     @JoinColumn(nullable = false)
-    private BankAccount giver;
+    private BankAccount giverAccount;
     @Column(nullable = false)
     private String beneficiaryAccountNumber;
     @Column(nullable = false)
diff --git a/src/main/java/net/kapcake/bankingservice/domain/User.java b/src/main/java/net/kapcake/bankingservice/model/entities/User.java
similarity index 74%
rename from src/main/java/net/kapcake/bankingservice/domain/User.java
rename to src/main/java/net/kapcake/bankingservice/model/entities/User.java
index 736463e..f58896a 100644
--- a/src/main/java/net/kapcake/bankingservice/domain/User.java
+++ b/src/main/java/net/kapcake/bankingservice/model/entities/User.java
@@ -1,10 +1,12 @@
-package net.kapcake.bankingservice.domain;
+package net.kapcake.bankingservice.model.entities;
 
 import jakarta.persistence.*;
 import lombok.Getter;
 import lombok.Setter;
 import lombok.experimental.Accessors;
 
+import java.util.List;
+
 @Entity
 @Table(name = "BANKING_USER")
 @Accessors(chain = true)
@@ -14,7 +16,6 @@ public class User {
     @Id
     @GeneratedValue
     private Long id;
-
     @Column(nullable = false)
     private String username;
     @Column(nullable = false)
@@ -24,4 +25,7 @@ public class User {
     private String numberExtension;
     private Integer postalCode;
     private String country;
+    @ManyToMany(mappedBy = "users", fetch = FetchType.EAGER)
+    private List<BankAccount> bankAccounts;
+
 }
diff --git a/src/main/java/net/kapcake/bankingservice/repositories/BankAccountRepository.java b/src/main/java/net/kapcake/bankingservice/repositories/BankAccountRepository.java
index 94124f8..6d0a11b 100644
--- a/src/main/java/net/kapcake/bankingservice/repositories/BankAccountRepository.java
+++ b/src/main/java/net/kapcake/bankingservice/repositories/BankAccountRepository.java
@@ -1,10 +1,11 @@
 package net.kapcake.bankingservice.repositories;
 
-import net.kapcake.bankingservice.domain.BankAccount;
+import net.kapcake.bankingservice.model.entities.BankAccount;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import java.util.List;
+import java.util.Optional;
 
 public interface BankAccountRepository extends JpaRepository<BankAccount, Long> {
-    List<BankAccount> findAllByUsers_username(String username);
+    Optional<List<BankAccount>> findAllByUsers_username(String username);
 }
diff --git a/src/main/java/net/kapcake/bankingservice/repositories/PaymentRepository.java b/src/main/java/net/kapcake/bankingservice/repositories/PaymentRepository.java
index bfbf504..0d1f769 100644
--- a/src/main/java/net/kapcake/bankingservice/repositories/PaymentRepository.java
+++ b/src/main/java/net/kapcake/bankingservice/repositories/PaymentRepository.java
@@ -1,6 +1,6 @@
 package net.kapcake.bankingservice.repositories;
 
-import net.kapcake.bankingservice.domain.Payment;
+import net.kapcake.bankingservice.model.entities.Payment;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 public interface PaymentRepository extends JpaRepository<Payment, Long> {
diff --git a/src/main/java/net/kapcake/bankingservice/repositories/UserRepository.java b/src/main/java/net/kapcake/bankingservice/repositories/UserRepository.java
index 2848a4f..e748dc7 100644
--- a/src/main/java/net/kapcake/bankingservice/repositories/UserRepository.java
+++ b/src/main/java/net/kapcake/bankingservice/repositories/UserRepository.java
@@ -1,6 +1,6 @@
 package net.kapcake.bankingservice.repositories;
 
-import net.kapcake.bankingservice.domain.User;
+import net.kapcake.bankingservice.model.entities.User;
 import org.springframework.data.jpa.repository.JpaRepository;
 
 import java.util.Optional;
diff --git a/src/main/java/net/kapcake/bankingservice/security/UserDetailsServiceImpl.java b/src/main/java/net/kapcake/bankingservice/security/UserDetailsServiceImpl.java
index 5f937f0..35f86a0 100644
--- a/src/main/java/net/kapcake/bankingservice/security/UserDetailsServiceImpl.java
+++ b/src/main/java/net/kapcake/bankingservice/security/UserDetailsServiceImpl.java
@@ -1,6 +1,6 @@
 package net.kapcake.bankingservice.security;
 
-import net.kapcake.bankingservice.domain.User;
+import net.kapcake.bankingservice.model.entities.User;
 import net.kapcake.bankingservice.repositories.UserRepository;
 import org.springframework.security.core.userdetails.UserDetails;
 import org.springframework.security.core.userdetails.UserDetailsService;
diff --git a/src/main/java/net/kapcake/bankingservice/services/AccountService.java b/src/main/java/net/kapcake/bankingservice/services/AccountService.java
index 7bbba09..d67180a 100644
--- a/src/main/java/net/kapcake/bankingservice/services/AccountService.java
+++ b/src/main/java/net/kapcake/bankingservice/services/AccountService.java
@@ -1,13 +1,14 @@
 package net.kapcake.bankingservice.services;
 
-import net.kapcake.bankingservice.domain.BankAccount;
+import net.kapcake.bankingservice.model.entities.BankAccount;
+import net.kapcake.bankingservice.model.entities.User;
 import net.kapcake.bankingservice.repositories.BankAccountRepository;
-import org.springframework.security.core.userdetails.User;
-import org.springframework.stereotype.Component;
+import org.springframework.stereotype.Service;
 
+import java.util.Collections;
 import java.util.List;
 
-@Component
+@Service
 public class AccountService {
     private final BankAccountRepository bankAccountRepository;
 
@@ -16,6 +17,6 @@ public class AccountService {
     }
 
     public List<BankAccount> getAccounts(User user) {
-        return bankAccountRepository.findAllByUsers_username(user.getUsername());
+        return bankAccountRepository.findAllByUsers_username(user.getUsername()).orElse(Collections.emptyList());
     }
 }