diff --git a/lib/jackson-annotations-2.13.3.jar b/lib/jackson-annotations-2.13.3.jar
new file mode 100644
index 0000000..60a3ddb
Binary files /dev/null and b/lib/jackson-annotations-2.13.3.jar differ
diff --git a/lib/jackson-core-2.13.3.jar b/lib/jackson-core-2.13.3.jar
new file mode 100644
index 0000000..7e2086d
Binary files /dev/null and b/lib/jackson-core-2.13.3.jar differ
diff --git a/lib/jackson-databind-2.13.3.jar b/lib/jackson-databind-2.13.3.jar
new file mode 100644
index 0000000..a27e9d7
Binary files /dev/null and b/lib/jackson-databind-2.13.3.jar differ
diff --git a/mtcg.iml b/mtcg.iml
index c90834f..3709e7d 100644
--- a/mtcg.iml
+++ b/mtcg.iml
@@ -7,5 +7,17 @@
     </content>
     <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module-library" scope="PROVIDED">
+      <library>
+        <CLASSES>
+          <root url="jar://$MAVEN_REPOSITORY$/org/projectlombok/lombok/1.18.30/lombok-1.18.30.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
+    <orderEntry type="library" name="fasterxml.jackson.core" level="project" />
+    <orderEntry type="library" name="fasterxml.jackson.core.annotations" level="project" />
+    <orderEntry type="library" name="fasterxml.jackson.core.databind" level="project" />
   </component>
 </module>
\ No newline at end of file
diff --git a/src/Main.java b/src/Main.java
index a79fddc..2d43d00 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -1,4 +1,5 @@
-import at.nanopenguin.mtcg.application.TestService;
+import at.nanopenguin.mtcg.application.service.TestService;
+import at.nanopenguin.mtcg.application.service.UserService;
 import at.nanopenguin.mtcg.http.HttpMethod;
 import at.nanopenguin.mtcg.http.Router;
 import at.nanopenguin.mtcg.http.Server;
@@ -11,10 +12,10 @@ public class Main {
         router.addRoute(HttpMethod.GET, "/test/{var}/service", new TestService(), new int[]{2});
 
         /* users */
-        router.addRoute(HttpMethod.POST, "/users", new TestService(), new int[]{});
-        router.addRoute(HttpMethod.GET, "/users/{username}", new TestService(), new int[]{2});
-        router.addRoute(HttpMethod.PUT, "/users/{username}", new TestService(), new int[]{2});
-        router.addRoute(HttpMethod.POST, "/sessions", new TestService(), new int[]{});
+        router.addRoute(HttpMethod.POST, "/users", new UserService(), new int[]{});
+        router.addRoute(HttpMethod.GET, "/users/{username}", new UserService(), new int[]{2});
+        router.addRoute(HttpMethod.PUT, "/users/{username}", new UserService(), new int[]{2});
+        router.addRoute(HttpMethod.POST, "/sessions", new UserService(), new int[]{});
 
         /* packages */
         router.addRoute(HttpMethod.POST, "/packages", new TestService(), new int[]{});
diff --git a/src/at/nanopenguin/mtcg/application/Service.java b/src/at/nanopenguin/mtcg/application/Service.java
deleted file mode 100644
index 41485a5..0000000
--- a/src/at/nanopenguin/mtcg/application/Service.java
+++ /dev/null
@@ -1,9 +0,0 @@
-package at.nanopenguin.mtcg.application;
-
-import at.nanopenguin.mtcg.http.HttpRequest;
-import at.nanopenguin.mtcg.http.Response;
-
-public interface Service {
-
-    Response handleRequest(HttpRequest request);
-}
diff --git a/src/at/nanopenguin/mtcg/application/User.java b/src/at/nanopenguin/mtcg/application/User.java
new file mode 100644
index 0000000..805dd5f
--- /dev/null
+++ b/src/at/nanopenguin/mtcg/application/User.java
@@ -0,0 +1,5 @@
+package at.nanopenguin.mtcg.application;
+
+public class User {
+
+}
diff --git a/src/at/nanopenguin/mtcg/application/InternalErrorService.java b/src/at/nanopenguin/mtcg/application/service/InternalErrorService.java
similarity index 78%
rename from src/at/nanopenguin/mtcg/application/InternalErrorService.java
rename to src/at/nanopenguin/mtcg/application/service/InternalErrorService.java
index e8407f6..d598c2c 100644
--- a/src/at/nanopenguin/mtcg/application/InternalErrorService.java
+++ b/src/at/nanopenguin/mtcg/application/service/InternalErrorService.java
@@ -1,5 +1,6 @@
-package at.nanopenguin.mtcg.application;
+package at.nanopenguin.mtcg.application.service;
 
+import at.nanopenguin.mtcg.application.service.Service;
 import at.nanopenguin.mtcg.http.HttpStatus;
 import at.nanopenguin.mtcg.http.HttpRequest;
 import at.nanopenguin.mtcg.http.Response;
diff --git a/src/at/nanopenguin/mtcg/application/service/Service.java b/src/at/nanopenguin/mtcg/application/service/Service.java
new file mode 100644
index 0000000..072ee8c
--- /dev/null
+++ b/src/at/nanopenguin/mtcg/application/service/Service.java
@@ -0,0 +1,10 @@
+package at.nanopenguin.mtcg.application.service;
+
+import at.nanopenguin.mtcg.http.HttpRequest;
+import at.nanopenguin.mtcg.http.Response;
+import com.fasterxml.jackson.core.JsonProcessingException;
+
+public interface Service {
+
+    Response handleRequest(HttpRequest request) throws JsonProcessingException;
+}
diff --git a/src/at/nanopenguin/mtcg/application/TestService.java b/src/at/nanopenguin/mtcg/application/service/TestService.java
similarity index 76%
rename from src/at/nanopenguin/mtcg/application/TestService.java
rename to src/at/nanopenguin/mtcg/application/service/TestService.java
index 8adb001..502ec38 100644
--- a/src/at/nanopenguin/mtcg/application/TestService.java
+++ b/src/at/nanopenguin/mtcg/application/service/TestService.java
@@ -1,5 +1,6 @@
-package at.nanopenguin.mtcg.application;
+package at.nanopenguin.mtcg.application.service;
 
+import at.nanopenguin.mtcg.application.service.Service;
 import at.nanopenguin.mtcg.http.HttpRequest;
 import at.nanopenguin.mtcg.http.HttpStatus;
 import at.nanopenguin.mtcg.http.Response;
diff --git a/src/at/nanopenguin/mtcg/application/service/UserService.java b/src/at/nanopenguin/mtcg/application/service/UserService.java
new file mode 100644
index 0000000..8566e3c
--- /dev/null
+++ b/src/at/nanopenguin/mtcg/application/service/UserService.java
@@ -0,0 +1,24 @@
+package at.nanopenguin.mtcg.application.service;
+
+import at.nanopenguin.mtcg.application.service.schemas.UserCredentials;
+import at.nanopenguin.mtcg.http.HttpRequest;
+import at.nanopenguin.mtcg.http.HttpStatus;
+import at.nanopenguin.mtcg.http.Response;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectWriter;
+
+public class UserService implements Service {
+
+    @Override
+    public Response handleRequest(HttpRequest request) throws JsonProcessingException {
+        UserCredentials userCredentials = new UserCredentials("test", "test");
+        ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
+        String json = ow.writeValueAsString(userCredentials);
+
+        System.out.println(json);
+
+        return new Response(HttpStatus.OK, "application/json", "");
+    }
+}
diff --git a/src/at/nanopenguin/mtcg/application/service/schemas/UserCredentials.java b/src/at/nanopenguin/mtcg/application/service/schemas/UserCredentials.java
new file mode 100644
index 0000000..ad019fc
--- /dev/null
+++ b/src/at/nanopenguin/mtcg/application/service/schemas/UserCredentials.java
@@ -0,0 +1,7 @@
+package at.nanopenguin.mtcg.application.service.schemas;
+
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
+
+@JsonSerialize
+public record UserCredentials(String username, String password) {
+}
diff --git a/src/at/nanopenguin/mtcg/http/RequestHandler.java b/src/at/nanopenguin/mtcg/http/RequestHandler.java
index fd7a669..b3452f4 100644
--- a/src/at/nanopenguin/mtcg/http/RequestHandler.java
+++ b/src/at/nanopenguin/mtcg/http/RequestHandler.java
@@ -1,6 +1,6 @@
 package at.nanopenguin.mtcg.http;
 
-import at.nanopenguin.mtcg.application.Service;
+import at.nanopenguin.mtcg.application.service.Service;
 
 import java.io.BufferedReader;
 import java.io.IOException;
diff --git a/src/at/nanopenguin/mtcg/http/Route.java b/src/at/nanopenguin/mtcg/http/Route.java
index b8f8c90..8c46be7 100644
--- a/src/at/nanopenguin/mtcg/http/Route.java
+++ b/src/at/nanopenguin/mtcg/http/Route.java
@@ -1,6 +1,6 @@
 package at.nanopenguin.mtcg.http;
 
-import at.nanopenguin.mtcg.application.Service;
+import at.nanopenguin.mtcg.application.service.Service;
 
 public record Route(Service service, boolean hasPathVariable) {
 }
diff --git a/src/at/nanopenguin/mtcg/http/Router.java b/src/at/nanopenguin/mtcg/http/Router.java
index 37be60e..3762e3b 100644
--- a/src/at/nanopenguin/mtcg/http/Router.java
+++ b/src/at/nanopenguin/mtcg/http/Router.java
@@ -1,6 +1,6 @@
 package at.nanopenguin.mtcg.http;
 
-import at.nanopenguin.mtcg.application.Service;
+import at.nanopenguin.mtcg.application.service.Service;
 
 import java.util.*;
 import java.util.stream.IntStream;