diff --git a/README.md b/README.md
index e5fc028..c9e71f0 100644
--- a/README.md
+++ b/README.md
@@ -125,3 +125,15 @@ The verification requests can be executed with: `src/test/resources/requests.sh`
 `PORT=9090 src/test/resources/requests.sh` if you want to run them to a different port.
 
 The health check endpoint is: http://localhost:18080/actuator/health
+
+### Stress Testing (Gatling)
+[Gatling settings] can be overridden creating a `gatling.conf` file at the test resources. The
+configuration options and their default values can be checked [here][gatlingDefaults].
+
+Those parameters can also be overwritten by system properties from the command line. I.e.:
+`-D gatling.core.encoding=utf-8`
+
+To run the Gatling test, execute `./mvnw gatling:test` at the shell.
+
+[Gatling settings]: https://docs.gatling.io/reference/script/core/configuration
+[gatlingDefaults]: https://github.com/gatling/gatling/blob/main/gatling-core/src/main/resources/gatling-defaults.conf
diff --git a/src/main/java/com/github/jaguililla/appointments/input/controllers/AppointmentsController.java b/src/main/java/com/github/jaguililla/appointments/input/controllers/AppointmentsController.java
index 96fcdb3..21a6a2c 100644
--- a/src/main/java/com/github/jaguililla/appointments/input/controllers/AppointmentsController.java
+++ b/src/main/java/com/github/jaguililla/appointments/input/controllers/AppointmentsController.java
@@ -36,7 +36,7 @@ public ResponseEntity<AppointmentResponse> createAppointment(
         final var createdAppointment = appointmentsService.create(appointment, users);
 
         final var responseAppointment = AppointmentsMapper.appointmentResponse(createdAppointment);
-        return ResponseEntity.ofNullable(responseAppointment);
+        return ResponseEntity.status(201).body(responseAppointment);
     }
 
     @Override
diff --git a/src/main/java/com/github/jaguililla/appointments/input/controllers/UsersController.java b/src/main/java/com/github/jaguililla/appointments/input/controllers/UsersController.java
index 7b5704b..963d017 100644
--- a/src/main/java/com/github/jaguililla/appointments/input/controllers/UsersController.java
+++ b/src/main/java/com/github/jaguililla/appointments/input/controllers/UsersController.java
@@ -30,6 +30,6 @@ public ResponseEntity<UserResponse> createUser(final UserRequest userRequest) {
         final var createdUser = appointmentsService.create(user);
 
         final var responseUser = UsersMapper.userResponse(createdUser);
-        return ResponseEntity.ofNullable(responseUser);
+        return ResponseEntity.status(201).body(responseUser);
     }
 }
diff --git a/src/main/resources/openapi/api.yml b/src/main/resources/openapi/api.yml
index 04b7e73..66f9707 100644
--- a/src/main/resources/openapi/api.yml
+++ b/src/main/resources/openapi/api.yml
@@ -19,7 +19,7 @@ paths:
             schema:
               $ref: 'schemas.yml#/components/schemas/UserRequest'
       responses:
-        "200":
+        "201":
           description: OK
           content:
             application/json:
@@ -36,7 +36,7 @@ paths:
             schema:
               $ref: 'schemas.yml#/components/schemas/AppointmentRequest'
       responses:
-        "200":
+        "201":
           description: OK
           content:
             application/json:
diff --git a/src/test/java/com/github/jaguililla/appointments/ApplicationIT.java b/src/test/java/com/github/jaguililla/appointments/ApplicationIT.java
index bed38bc..df77bad 100644
--- a/src/test/java/com/github/jaguililla/appointments/ApplicationIT.java
+++ b/src/test/java/com/github/jaguililla/appointments/ApplicationIT.java
@@ -99,7 +99,7 @@ void appointments_can_be_created_read_and_deleted() {
             .endTimestamp(LocalDateTime.now())
         );
         var response = client.getResponseBody(AppointmentResponse.class);
-        assertEquals(200, client.getResponseStatus().value());
+        assertEquals(201, client.getResponseStatus().value());
         assertTrue(getLastMessage().startsWith("Appointment created at"));
         client.get("/appointments/" + response.getId());
         assertEquals(200, client.getResponseStatus().value());
diff --git a/src/test/java/com/github/jaguililla/appointments/GatlingSimulation.java b/src/test/java/com/github/jaguililla/appointments/GatlingSimulation.java
index 2f40885..d9643a0 100644
--- a/src/test/java/com/github/jaguililla/appointments/GatlingSimulation.java
+++ b/src/test/java/com/github/jaguililla/appointments/GatlingSimulation.java
@@ -8,12 +8,19 @@
 public class GatlingSimulation extends Simulation {
 
     private ChainBuilder appointmentsCrud = exec(
-        http("Create").post("/appointments").check(status().is(201)),
+        http("Create")
+            .post("/appointments")
+            .body(StringBody(""))
+            .check(status().is(201))
+            .check(jmesPath("id").saveAs("id")),
         pause(1),
-        http("Read").get("/appointments").check(status().is(200)),
+        http("Read")
+            .get("/appointments/#{id}")
+            .check(status().is(200)),
         pause(1),
-        http("Delete").delete("/appointments").check(status().is(200)),
-        pause(1)
+        http("Delete")
+            .delete("/appointments/#{id}")
+            .check(status().is(200))
     );
 
     {