diff --git a/src/main/java/envoy/client/Client.java b/src/main/java/envoy/client/Client.java
index f302a39..53a7865 100644
--- a/src/main/java/envoy/client/Client.java
+++ b/src/main/java/envoy/client/Client.java
@@ -17,6 +17,7 @@ import envoy.schema.Message;
 import envoy.schema.Message.MetaData.MessageState;
 import envoy.schema.Messages;
 import envoy.schema.ObjectFactory;
+import envoy.schema.User;
 import envoy.schema.Users;
 
 /**
@@ -26,6 +27,7 @@ import envoy.schema.Users;
  * 
  * @author Kai S. K. Engelbart
  * @author Maximilian Käfer
+ * @author Leon Hofmeister
  * @since Envoy 0.1
  */
 
@@ -34,14 +36,17 @@ public class Client {
 	private ObjectFactory	objectFactory	= new ObjectFactory();
 	private DatatypeFactory	datatypeFactory;
 	private Config			config;
+	private User			user;
 
-	public Client(Config config) {
+	public Client(Config config, String username) {
 		this.config = config;
 		try {
 			datatypeFactory = DatatypeFactory.newInstance();
 		} catch (DatatypeConfigurationException e) {
 			e.printStackTrace();
 		}
+		user = getUser(username);
+		System.out.printf("Mein Name ist %s und ich habe die ID %d%n", user.getName(), user.getID());
 	}
 
 	/**
@@ -49,9 +54,9 @@ public class Client {
 	 * Because sending a request is a blocking operation, it is executed
 	 * asynchronously.
 	 * 
-	 * @param sender      Name of the sender
-	 * @param recipient   Name of the recipient
-	 * @param textContent Content (text) of the message
+	 * @param sender      name of the sender
+	 * @param recipient   name of the recipient
+	 * @param textContent content (text) of the message
 	 */
 	public void sendMessage(Message message) {
 		new Thread(() -> {
@@ -87,7 +92,7 @@ public class Client {
 	 * @param senderID    The ID of the sender
 	 * @param recipientID The ID of the recipient
 	 * @param textContent The content (text) of the message
-	 * @return Prepared {@link Message} object
+	 * @return prepared {@link Message} object
 	 */
 	public Message createMessage(long senderID, long recipientID, String textContent) {
 		Message.MetaData metaData = objectFactory.createMessageMetaData();
@@ -124,4 +129,29 @@ public class Client {
 		client.close();
 		return users;
 	}
+
+	/**
+	 * Returns a {@link User} with a specific name by name.
+	 * 
+	 * @param name - the name of the {@link User}
+	 * @return a {@link User} with the specified name
+	 * @since Envoy 0.1
+	 */
+	private User getUser(String name) {
+		javax.ws.rs.client.Client	client		= ClientBuilder.newClient();
+		WebTarget					target		= client.target(String
+			.format("%s:%d/envoy-server/rest/user/sender?name=" + name, config.getServer(), config.getPort()));
+		Response					response	= target.request("application/xml").get();
+		Users						users		= response.readEntity(Users.class);
+		System.out.println("Response code: " + response.getStatus());
+		response.close();
+		client.close();
+		return users.getUser().get(0);
+	}
+
+	/**
+	 * @return the user id of this client
+	 * @since Envoy 0.1
+	 */
+	public long getSenderID() { return user.getID(); }
 }
\ No newline at end of file
diff --git a/src/main/java/envoy/client/ui/ChatWindow.java b/src/main/java/envoy/client/ui/ChatWindow.java
index 6e4891d..0e9bc40 100644
--- a/src/main/java/envoy/client/ui/ChatWindow.java
+++ b/src/main/java/envoy/client/ui/ChatWindow.java
@@ -2,13 +2,10 @@ package envoy.client.ui;
 
 import java.awt.Color;
 import java.awt.ComponentOrientation;
-import java.awt.EventQueue;
 import java.awt.Font;
 import java.awt.GridBagConstraints;
 import java.awt.GridBagLayout;
 import java.awt.Insets;
-import java.io.IOException;
-import java.util.Properties;
 
 import javax.swing.DefaultListModel;
 import javax.swing.JButton;
@@ -23,7 +20,6 @@ import javax.swing.SwingUtilities;
 import javax.swing.border.EmptyBorder;
 
 import envoy.client.Client;
-import envoy.client.Config;
 import envoy.schema.Message;
 import envoy.schema.User;
 import envoy.schema.Users;
@@ -35,6 +31,7 @@ import envoy.schema.Users;
  * 
  * @author Kai S. K. Engelbart
  * @author Maximilian Käfer
+ * @author Leon Hofmeister
  * @since Envoy 0.1
  */
 public class ChatWindow extends JFrame {
@@ -44,11 +41,13 @@ public class ChatWindow extends JFrame {
 	private long	recipientID	= 0;
 	private JPanel	contentPane	= new JPanel();
 
-	private static Client client;
+	private Client client;
 
 	private DefaultListModel<String> messageListModel = new DefaultListModel<>();
 
-	public ChatWindow() {
+	public ChatWindow(Client client) {
+		this.client = client;
+
 		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 		setBounds(100, 100, 600, 800);
 		setTitle("Envoy");
@@ -135,7 +134,8 @@ public class ChatWindow extends JFrame {
 
 			// TODO: Acquire proper sender id
 			if (!messageEnterTextfield.getText().isEmpty() && recipientID != 0) try {
-				final Message message = client.createMessage(1, recipientID, messageEnterTextfield.getText());
+				final Message message = client
+					.createMessage(client.getSenderID(), recipientID, messageEnterTextfield.getText());
 				client.sendMessage(message);
 				appendMessageToChat(message);
 				messageEnterTextfield.setText("");
@@ -211,36 +211,4 @@ public class ChatWindow extends JFrame {
 				+ message.getMetaData().getSender() + "</b> </small>" + "<br>" + "<p style=\"color:white\">"
 				+ getFirstTextContent(message) + "</span></html>");
 	}
-
-	public static void main(String[] args) {
-		Config config = new Config();
-		if (args.length > 0) {
-			config.load(args);
-		} else {
-			ClassLoader loader = Thread.currentThread().getContextClassLoader();
-			try {
-				Properties configProperties = new Properties();
-				configProperties.load(loader.getResourceAsStream("server.properties"));
-				config.load(configProperties);
-			} catch (IOException e) {
-				e.printStackTrace();
-			}
-		}
-
-		if(!config.isInitialized()) {
-			System.err.println("Server or port are not defined. Exiting...");
-			System.exit(1);
-		}
-		
-		client = new Client(config);
-
-		EventQueue.invokeLater(() -> {
-			try {
-				ChatWindow frame = new ChatWindow();
-				frame.setVisible(true);
-			} catch (Exception e) {
-				e.printStackTrace();
-			}
-		});
-	}
 }
\ No newline at end of file
diff --git a/src/main/java/envoy/client/ui/Startup.java b/src/main/java/envoy/client/ui/Startup.java
new file mode 100644
index 0000000..b525861
--- /dev/null
+++ b/src/main/java/envoy/client/ui/Startup.java
@@ -0,0 +1,61 @@
+package envoy.client.ui;
+
+import java.awt.EventQueue;
+import java.io.IOException;
+import java.util.Properties;
+
+import javax.swing.JOptionPane;
+
+import envoy.client.Client;
+import envoy.client.Config;
+
+/**
+ * Starts the Envoy client and prompts the user to enter their name.
+ * 
+ * Project: <strong>envoy-client</strong><br>
+ * File: <strong>Startup.java</strong><br>
+ * Created: <strong>12 Oct 2019</strong><br>
+ * 
+ * @author Leon Hofmeister
+ * @author Maximilian K&auml;fer
+ * @since Envoy 0.1
+ */
+public class Startup {
+
+	public static void main(String[] args) {
+		Config config = new Config();
+		if (args.length > 0) {
+			config.load(args);
+		} else {
+			ClassLoader loader = Thread.currentThread().getContextClassLoader();
+			try {
+				Properties configProperties = new Properties();
+				configProperties.load(loader.getResourceAsStream("server.properties"));
+				config.load(configProperties);
+			} catch (IOException e) {
+				e.printStackTrace();
+			}
+		}
+
+		if (!config.isInitialized()) {
+			System.err.println("Server or port are not defined. Exiting...");
+			System.exit(1);
+		}
+
+		String userName = JOptionPane.showInputDialog("Please enter your username");
+		if (userName == null || userName.isEmpty()) {
+			System.err.println("User name is not set or empty. Exiting...");
+			System.exit(1);
+		}
+		Client client = new Client(config, userName);
+
+		EventQueue.invokeLater(() -> {
+			try {
+				ChatWindow frame = new ChatWindow(client);
+				frame.setVisible(true);
+			} catch (Exception e) {
+				e.printStackTrace();
+			}
+		});
+	}
+}
\ No newline at end of file