diff --git a/pom.xml b/pom.xml
index 41e27e1..d5e1dc6 100644
--- a/pom.xml
+++ b/pom.xml
@@ -56,8 +56,29 @@
             <version>1.60</version>
         </dependency>
         <!-- ***** -->
+
+        <!-- ORMLITE - POSTGRE -->
+        <dependency>
+            <groupId>com.j256.ormlite</groupId>
+            <artifactId>ormlite-core</artifactId>
+            <version>5.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.j256.ormlite</groupId>
+            <artifactId>ormlite-jdbc</artifactId>
+            <version>5.1</version>
+        </dependency>
+
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>42.2.5</version>
+        </dependency>
+        <!-- ***** -->
     </dependencies>
 
+
     <properties>
         <java.version>1.8</java.version>
     </properties>
diff --git a/src/main/java/Application/App.java b/src/main/java/application/App.java
similarity index 97%
rename from src/main/java/Application/App.java
rename to src/main/java/application/App.java
index a122df1..a20e040 100644
--- a/src/main/java/Application/App.java
+++ b/src/main/java/application/App.java
@@ -1,4 +1,4 @@
-package Application;
+package application;
 
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.SpringApplication;
diff --git a/src/main/java/database/DatabaseHelper.java b/src/main/java/database/DatabaseHelper.java
new file mode 100644
index 0000000..d511d1d
--- /dev/null
+++ b/src/main/java/database/DatabaseHelper.java
@@ -0,0 +1,20 @@
+package database;
+
+import com.j256.ormlite.jdbc.JdbcConnectionSource;
+import com.j256.ormlite.support.ConnectionSource;
+
+public class DatabaseHelper {
+    private static final String DATABASE_NAME = "monnethic";
+    private static final String DATABASE_USER = "";
+    private static final String DATABASE_PWD = "";
+    private final static String DATABASE_URL = "jdbc:postgresql://host:port/"+DATABASE_NAME;
+
+    public ConnectionSource setupDatabaseConnection(){
+        try{
+            return new JdbcConnectionSource(DATABASE_URL, DATABASE_USER, DATABASE_PWD);
+        }catch (Exception e){
+            System.out.print("\n"+e.getMessage());
+            return null;
+        }
+    }
+}
diff --git a/src/main/java/database/DatabaseTest.java b/src/main/java/database/DatabaseTest.java
new file mode 100644
index 0000000..f2c3c53
--- /dev/null
+++ b/src/main/java/database/DatabaseTest.java
@@ -0,0 +1,38 @@
+package database;
+
+import com.j256.ormlite.field.DatabaseField;
+import com.j256.ormlite.table.DatabaseTable;
+
+@DatabaseTable(tableName = "T_TEST")
+public class DatabaseTest {
+    private static final String NAME_FIELD_NAME = "name";
+    private static final String ID_FIELD_NAME = "id";
+
+    @DatabaseField(columnName = ID_FIELD_NAME, id = true)
+    private int id;
+    @DatabaseField(columnName = NAME_FIELD_NAME, canBeNull = false)
+    private String name;
+
+    public DatabaseTest(int id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+
+    public DatabaseTest() { }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}
diff --git a/src/main/java/database/transaction/Transaction.java b/src/main/java/database/transaction/Transaction.java
new file mode 100644
index 0000000..85aa124
--- /dev/null
+++ b/src/main/java/database/transaction/Transaction.java
@@ -0,0 +1,106 @@
+package database.transaction;
+
+import com.j256.ormlite.field.DatabaseField;
+import com.j256.ormlite.table.DatabaseTable;
+
+import java.math.BigInteger;
+import java.util.Date;
+
+@DatabaseTable(tableName = "T_TRANSACTION")
+public class Transaction {
+    @DatabaseField(columnName = "transactionId", generatedId = true, unique = true)
+    private int id;
+    @DatabaseField(columnName = "transactionDate")
+    private Date transactionDate;
+    @DatabaseField(columnName = "transactionDSrcAddress")
+    private String sourceAddress;
+    @DatabaseField(columnName = "transactionDestAddress")
+    private String destAddress;
+    @DatabaseField(columnName = "transactionHash")
+    private String transactionHash;
+    @DatabaseField(columnName = "transactionBlockNumber")
+    private String blockNumber;
+    @DatabaseField(columnName = "transactionAmout")
+    private BigInteger amount;
+    @DatabaseField(columnName = "transactionUnit")
+    private String unit;
+
+    public Transaction() {
+        super();
+    }
+
+    public Transaction(Date transactionDate, String sourceAddress, String destAddress, String transactionHash, String blockNumber, BigInteger amount, String unit) {
+        super();
+        this.transactionDate = transactionDate;
+        this.sourceAddress = sourceAddress;
+        this.destAddress = destAddress;
+        this.transactionHash = transactionHash;
+        this.blockNumber = blockNumber;
+        this.amount = amount;
+        this.unit = unit;
+    }
+
+    public String getSourceAddress() {
+        return sourceAddress;
+    }
+
+    public void setSourceAddress(String sourceAddress) {
+        this.sourceAddress = sourceAddress;
+    }
+
+    public String getDestAddress() {
+        return destAddress;
+    }
+
+    public void setDestAddress(String destAddress) {
+        this.destAddress = destAddress;
+    }
+
+    public String getTransactionHash() {
+        return transactionHash;
+    }
+
+    public void setTransactionHash(String transactionHash) {
+        this.transactionHash = transactionHash;
+    }
+
+    public BigInteger getAmount() {
+        return amount;
+    }
+
+    public void setAmount(BigInteger amount) {
+        this.amount = amount;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public Date getTransactionDate() {
+        return transactionDate;
+    }
+
+    public void setTransactionDate(Date transactionDate) {
+        this.transactionDate = transactionDate;
+    }
+
+    public String getUnit() {
+        return unit;
+    }
+
+    public void setUnit(String unit) {
+        this.unit = unit;
+    }
+
+    public String getBlockNumber() {
+        return blockNumber;
+    }
+
+    public void setBlockNumber(String blockNumber) {
+        this.blockNumber = blockNumber;
+    }
+}
diff --git a/src/main/java/database/user/User.java b/src/main/java/database/user/User.java
new file mode 100644
index 0000000..851f2a3
--- /dev/null
+++ b/src/main/java/database/user/User.java
@@ -0,0 +1,115 @@
+package database.user;
+
+import com.j256.ormlite.field.DatabaseField;
+import com.j256.ormlite.table.DatabaseTable;
+
+//Class User which represent an User in the postgresDB
+@DatabaseTable(tableName = "T_USER")
+public class User {
+    @DatabaseField(canBeNull = false)
+    private String name;
+    @DatabaseField(canBeNull = false)
+    private String firstname;
+    @DatabaseField(id = true)
+    private String email;
+    @DatabaseField(canBeNull = false)
+    private String password;
+    @DatabaseField(canBeNull = false)
+    private long creation_date;
+    @DatabaseField(canBeNull = false)
+    private long modification_date;
+    @DatabaseField(canBeNull = false)
+    private boolean verified;
+    @DatabaseField(canBeNull = false)
+    private boolean approved;
+
+    //Constructors
+    //Default constructor for ORMLite
+    public User() {
+    }
+
+    public User(String name, String firstname, String email, String password) {
+        this.name = name;
+        this.firstname = firstname;
+        this.email = email;
+        this.password = password;
+    }
+
+    public User(String name, String firstname, String email, String password, long creation_date, long modification_date, boolean verified, boolean approved) {
+        this.name = name;
+        this.firstname = firstname;
+        this.email = email;
+        this.password = password;
+        this.creation_date = creation_date;
+        this.modification_date = modification_date;
+        this.verified = verified;
+        this.approved = approved;
+    }
+
+
+    //Getters and Setters
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getFirstname() {
+        return firstname;
+    }
+
+    public void setFirstname(String firstname) {
+        this.firstname = firstname;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+
+    public long getCreation_date() {
+        return creation_date;
+    }
+
+    public void setCreation_date(long creation_date) {
+        this.creation_date = creation_date;
+    }
+
+    public long getModification_date() {
+        return modification_date;
+    }
+
+    public void setModification_date(long modification_date) {
+        this.modification_date = modification_date;
+    }
+
+    public boolean isVerified() {
+        return verified;
+    }
+
+    public void setVerified(boolean verified) {
+        this.verified = verified;
+    }
+
+    public boolean isApproved() {
+        return approved;
+    }
+
+    public void setApproved(boolean approved) {
+        this.approved = approved;
+    }
+
+}
diff --git a/src/main/java/database/user/UserDao.java b/src/main/java/database/user/UserDao.java
new file mode 100644
index 0000000..307b0eb
--- /dev/null
+++ b/src/main/java/database/user/UserDao.java
@@ -0,0 +1,119 @@
+package database.user;
+
+import com.j256.ormlite.dao.Dao;
+import com.j256.ormlite.dao.DaoManager;
+import com.j256.ormlite.stmt.PreparedQuery;
+import com.j256.ormlite.stmt.QueryBuilder;
+import com.j256.ormlite.stmt.UpdateBuilder;
+import database.DatabaseHelper;
+
+import java.sql.Timestamp;
+
+//Class to communicate with database with ORMLite
+public class UserDao {
+    private DatabaseHelper dbh = new DatabaseHelper();
+    private Dao<User, String> userDao;
+
+    public Dao createUserDaoConnection(){
+        try {
+            return DaoManager.createDao(dbh.setupDatabaseConnection(),User.class);
+        }catch (Exception e){
+            System.out.println(e.getMessage());
+            return null;
+        }
+    }
+
+    public void addUser(User user)throws Exception {
+        userDao = createUserDaoConnection();
+        userDao.create(user);
+    }
+
+    public boolean checkApprovedUser(String email) throws Exception {
+        userDao = createUserDaoConnection();
+        QueryBuilder<User, String> queryBuilder = userDao.queryBuilder();
+        queryBuilder.where().eq("email",email);
+        PreparedQuery<User> preparedQuery = queryBuilder.prepare();
+        User user = userDao.queryForFirst(preparedQuery);
+        return user.isApproved();
+    }
+
+    public boolean checkVerifiedUser(String email) throws Exception {
+        userDao = createUserDaoConnection();
+        QueryBuilder<User, String> queryBuilder = userDao.queryBuilder();
+        queryBuilder.where().eq("email",email);
+        PreparedQuery<User> preparedQuery = queryBuilder.prepare();
+        User user = userDao.queryForFirst(preparedQuery);
+        return user.isVerified();
+    }
+
+    public boolean updateUserPassword(String email, String password) throws Exception {
+        userDao = createUserDaoConnection();
+        UpdateBuilder<User, String> updateBuilder = userDao.updateBuilder();
+        updateBuilder.updateColumnValue("password",password);
+        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
+        updateBuilder.updateColumnValue("modification_date",timestamp.getTime());
+        updateBuilder.where().eq("email",email);
+        updateBuilder.update();
+
+        if(checkUserPassword(email, password)){
+            return true;
+        }else{
+            return false;
+        }
+    }
+
+    private boolean verifyUserExist(String email) throws Exception {
+        userDao = createUserDaoConnection();
+        QueryBuilder<User, String> queryBuilder = userDao.queryBuilder();
+        queryBuilder.where().eq("email",email);
+        PreparedQuery<User> preparedQuery = queryBuilder.prepare();
+        User user = userDao.queryForFirst(preparedQuery);
+
+        if(user==null){
+            return false;
+        }else{
+            return true;
+        }
+    }
+
+    public boolean checkUserPassword(String email, String password) throws Exception {
+        User user = getUser(email);
+        if(password.equals(user.getPassword())){
+            return true;
+        }else{
+            return false;
+        }
+    }
+
+    public User getUser(String email) throws Exception {
+        if(!verifyUserExist(email)){
+            return null;
+        }else{
+            userDao = createUserDaoConnection();
+            QueryBuilder<User, String> queryBuilder = userDao.queryBuilder();
+            queryBuilder.where().eq("email",email);
+            PreparedQuery<User> preparedQuery = queryBuilder.prepare();
+            return userDao.queryForFirst(preparedQuery);
+        }
+    }
+
+
+    public void approveUser (String email) throws Exception{
+        userDao = createUserDaoConnection();
+        UpdateBuilder<User, String> updateBuilder = userDao.updateBuilder();
+        updateBuilder.updateColumnValue("approved",true);
+        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
+        updateBuilder.updateColumnValue("modification_date",timestamp.getTime());
+        updateBuilder.where().eq("email",email);
+        updateBuilder.update();
+    }
+    public void verifyUser (String email) throws Exception{
+        userDao = createUserDaoConnection();
+        UpdateBuilder<User, String> updateBuilder = userDao.updateBuilder();
+        updateBuilder.updateColumnValue("verified",true);
+        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
+        updateBuilder.updateColumnValue("modification_date",timestamp.getTime());
+        updateBuilder.where().eq("email",email);
+        updateBuilder.update();
+    }
+}
diff --git a/src/test/java/database/DatabaseHelperTest.java b/src/test/java/database/DatabaseHelperTest.java
new file mode 100644
index 0000000..02dea81
--- /dev/null
+++ b/src/test/java/database/DatabaseHelperTest.java
@@ -0,0 +1,26 @@
+package database;
+
+import com.j256.ormlite.dao.Dao;
+import com.j256.ormlite.dao.DaoManager;
+import org.junit.Test;
+
+//Testing class for postgresql connection
+public class DatabaseHelperTest {
+    private DatabaseHelper dbh = new DatabaseHelper();
+
+    //Test connection by getting existing data in T_TEST
+    @Test
+    public void TestConnection(){
+        Dao<DatabaseTest, Integer> testDao;
+        try{
+            testDao = DaoManager.createDao(dbh.setupDatabaseConnection(),DatabaseTest.class);
+            DatabaseTest dbt = testDao.queryForId(1);
+            System.out.println(dbt.getName());
+            assert dbt != null;
+            assert "thomas".equals(dbt.getName());
+        }catch (Exception e){
+            System.out.println("\n"+e.getMessage());
+        }
+    }
+
+}