diff --git a/api/pom.xml b/api/pom.xml
index 4cc60f5..40e5d0b 100644
--- a/api/pom.xml
+++ b/api/pom.xml
@@ -129,6 +129,11 @@
             <artifactId>ktorm-support-mysql</artifactId>
             <version>${ktorm_version}</version>
         </dependency>
+        <dependency>
+            <groupId>me.liuwj.ktorm</groupId>
+            <artifactId>ktorm-jackson</artifactId>
+            <version>${ktorm_version}</version>
+        </dependency>
         <dependency>
             <groupId>com.github.hekeki</groupId>
             <artifactId>huckleberry</artifactId>
@@ -179,6 +184,18 @@
             <version>1.61</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.skyscreamer</groupId>
+            <artifactId>jsonassert</artifactId>
+            <version>1.5.0</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>io.mockk</groupId>
+            <artifactId>mockk</artifactId>
+            <version>1.10.0</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
     <build>
         <sourceDirectory>${project.basedir}/src</sourceDirectory>
diff --git a/api/src/entities/User.kt b/api/src/entities/User.kt
index aacb825..0400eb2 100644
--- a/api/src/entities/User.kt
+++ b/api/src/entities/User.kt
@@ -12,4 +12,4 @@ interface User : Entity<User> {
     var password: String
     var createdAt: LocalDateTime
     var lastLogin: LocalDateTime?
-}
\ No newline at end of file
+}
diff --git a/api/src/extensions/ApplicationCallExtensions.kt b/api/src/extensions/ApplicationCallExtensions.kt
index 97abb62..a170e75 100644
--- a/api/src/extensions/ApplicationCallExtensions.kt
+++ b/api/src/extensions/ApplicationCallExtensions.kt
@@ -1,19 +1,16 @@
 package be.vandewalleh.extensions
 
 import be.vandewalleh.auth.UserDbIdPrincipal
-import be.vandewalleh.kodein
 import be.vandewalleh.services.FullNoteCreateDTO
 import be.vandewalleh.services.FullNotePatchDTO
-import be.vandewalleh.services.UserService
 import io.ktor.application.*
 import io.ktor.auth.*
 import io.ktor.http.*
 import io.ktor.request.*
 import io.ktor.response.*
-import org.kodein.di.generic.instance
 
 suspend fun ApplicationCall.respondStatus(status: HttpStatusCode) {
-    respond(status, status.description)
+    respond(status, """{"msg": "${status.description}"}""")
 }
 
 /**
diff --git a/api/src/features/ContentNegotiationFeature.kt b/api/src/features/ContentNegotiationFeature.kt
index df99c0a..fe892c5 100644
--- a/api/src/features/ContentNegotiationFeature.kt
+++ b/api/src/features/ContentNegotiationFeature.kt
@@ -3,9 +3,12 @@ package be.vandewalleh.features
 import io.ktor.application.*
 import io.ktor.features.*
 import io.ktor.jackson.*
+import me.liuwj.ktorm.jackson.*
 
 fun Application.contentNegotiationFeature() {
     install(ContentNegotiation) {
-        jackson {}
+        jackson {
+            registerModule(KtormModule())
+        }
     }
-}
\ No newline at end of file
+}
diff --git a/api/src/routing/UserController.kt b/api/src/routing/UserController.kt
index 05245ae..bbdbea9 100644
--- a/api/src/routing/UserController.kt
+++ b/api/src/routing/UserController.kt
@@ -1,5 +1,6 @@
 package be.vandewalleh.routing
 
+import be.vandewalleh.entities.User
 import be.vandewalleh.extensions.respondStatus
 import be.vandewalleh.extensions.userId
 import be.vandewalleh.services.UserService
@@ -12,16 +13,22 @@ import io.ktor.routing.*
 import org.kodein.di.Kodein
 import org.kodein.di.generic.instance
 import org.mindrot.jbcrypt.BCrypt
+import java.time.LocalDateTime
 
 fun Routing.user(kodein: Kodein) {
     val userService by kodein.instance<UserService>()
 
+    post("/user/test") {
+        val user = call.receive<User>()
+        call.respond(user)
+    }
+
     route("/user") {
         post {
-            val user = call.receive<UserDto>()
+            val user = call.receive<User>()
 
             if (userService.userExists(user.username, user.email))
-                return@post call.respond(HttpStatusCode.Conflict)
+                return@post call.respondStatus(HttpStatusCode.Conflict)
 
             val hashedPassword = BCrypt.hashpw(user.password, BCrypt.gensalt())
 
@@ -32,7 +39,7 @@ fun Routing.user(kodein: Kodein) {
 
         authenticate {
             put {
-                val user = call.receive<UserDto>()
+                val user = call.receive<User>()
 
                 if (userService.userExists(user.username, user.email))
                     return@put call.respond(HttpStatusCode.Conflict)
@@ -45,12 +52,13 @@ fun Routing.user(kodein: Kodein) {
             }
 
             delete {
-                userService.deleteUser(call.userId())
-                call.respondStatus(HttpStatusCode.OK)
+                val status = if (userService.deleteUser(call.userId()))
+                    HttpStatusCode.OK
+                else
+                    HttpStatusCode.NotFound
+                call.respondStatus(status)
             }
         }
 
     }
 }
-
-private data class UserDto(val username: String, val email: String, val password: String)
diff --git a/api/src/services/UserService.kt b/api/src/services/UserService.kt
index 8a5f05a..fc93555 100644
--- a/api/src/services/UserService.kt
+++ b/api/src/services/UserService.kt
@@ -98,9 +98,13 @@ class UserService(override val kodein: Kodein) : KodeinAware {
         }
     }
 
-    fun deleteUser(userId: Int) {
+    fun deleteUser(userId: Int): Boolean {
         db.useTransaction {
-            db.delete(Users) { it.id eq userId }
+            return when (db.delete(Users) { it.id eq userId }) {
+                1 -> true
+                0 -> false
+                else -> error("??")
+            }
         }
     }
 }
diff --git a/api/test/routing/UserControllerKtTest.kt b/api/test/routing/UserControllerKtTest.kt
new file mode 100644
index 0000000..8e521fc
--- /dev/null
+++ b/api/test/routing/UserControllerKtTest.kt
@@ -0,0 +1,142 @@
+package routing
+
+import be.vandewalleh.auth.SimpleJWT
+import be.vandewalleh.entities.User
+import be.vandewalleh.mainModule
+import be.vandewalleh.module
+import be.vandewalleh.services.UserService
+import io.ktor.http.*
+import io.ktor.server.testing.*
+import io.mockk.every
+import io.mockk.mockk
+import org.amshove.kluent.*
+import org.junit.jupiter.api.*
+import org.kodein.di.Kodein
+import org.kodein.di.generic.bind
+import org.kodein.di.generic.instance
+import utils.*
+import java.time.LocalDateTime
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+class UserControllerKtTest {
+
+    private val userService = mockk<UserService>()
+
+    init {
+        // new user
+        every { userService.userExists("new", "new@test.com") } returns false
+        every { userService.createUser("new", "new@test.com", any()) } returns User {
+            this.createdAt = LocalDateTime.now()
+            this.username = "new"
+            this.email = "new@test.com"
+        }
+
+        // existing user
+        every { userService.userExists("existing", "existing@test.com") } returns true
+        every { userService.createUser("existing", "existing@test.com", any()) } returns null
+        every { userService.getUserId("existing@test.com") } returns 1
+        every { userService.deleteUser(1) } returns true andThen false
+
+        // modified user
+        every { userService.userExists("modified", "modified@test.com") } returns true
+        every {
+            userService.userExists(
+                and(not("modified"), not("existing")),
+                and(not("modified@test.com"), not("existing@test.com"))
+            )
+        } returns false
+        every { userService.userExists(1) } returns true
+        every { userService.createUser("modified", "modified@test.com", any()) } returns null
+        every { userService.getUserId("modified@test.com") } returns 1
+        every { userService.updateUser(1, "ThisIsMyNewName", "ThisIsMyNewName@mail.com", any()) } returns Unit
+
+    }
+
+
+    private val kodein = Kodein {
+        import(mainModule, allowOverride = true)
+        bind<UserService>(overrides = true) with instance(userService)
+    }
+
+    private val testEngine = TestApplicationEngine().apply {
+        start()
+        application.module(kodein)
+    }
+
+    @Nested
+    inner class CreateUser {
+        @Test
+        fun `create a new user`() {
+            val res = testEngine.post("/user") {
+                json {
+                    it["username"] = "new"
+                    it["password"] = "test"
+                    it["email"] = "new@test.com"
+                }
+            }
+            res.status() `should be equal to` HttpStatusCode.Created
+            res.content `should be equal to json` """{msg:"Created"}"""
+        }
+
+        @Test
+        fun `create an existing user`() {
+            val res = testEngine.post("/user") {
+                json {
+                    it["username"] = "existing"
+                    it["email"] = "existing@test.com"
+                    it["password"] = "test"
+                }
+            }
+            res.status() `should be equal to` HttpStatusCode.Conflict
+            res.content `should be equal to json` """{msg:"Conflict"}"""
+        }
+    }
+
+
+    @Nested
+    inner class DeleteUser {
+
+        @Test
+        fun `delete an existing user`() {
+            val authJwt by kodein.instance<SimpleJWT>("auth")
+            val token = authJwt.sign(1)
+
+            val res = testEngine.delete("/user") {
+                addHeader(HttpHeaders.Authorization, "Bearer $token")
+            }
+            res.status() `should be equal to` HttpStatusCode.OK
+            res.content `should be equal to json` """{msg:"OK"}"""
+
+            // try again
+            val res2 = testEngine.delete("/user") {
+                setToken(token)
+            }
+            res2.status() `should be equal to` HttpStatusCode.NotFound
+            res2.content `should be equal to json` """{msg:"Not Found"}"""
+        }
+    }
+
+    @Nested
+    inner class ModifyUser {
+
+        @Test
+        fun `modify a user`() {
+            val authJwt by kodein.instance<SimpleJWT>("auth")
+            val token = authJwt.sign(1)
+
+            val res = testEngine.put("/user") {
+                setToken(token)
+                json {
+                    it["username"] = "ThisIsMyNewName"
+                    it["email"] = "ThisIsMyNewName@mail.com"
+                }
+            }
+
+            res.status() `should be equal to` HttpStatusCode.OK
+            res.content `should be equal to json` """{msg:"OK"}"""
+
+        }
+    }
+
+
+}
diff --git a/api/test/utils/Assertions.kt b/api/test/utils/Assertions.kt
new file mode 100644
index 0000000..6b9bad8
--- /dev/null
+++ b/api/test/utils/Assertions.kt
@@ -0,0 +1,19 @@
+package utils
+
+import org.skyscreamer.jsonassert.JSONAssert
+
+infix fun String?.shouldBeEqualToJson(expected: String?) = JSONAssert.assertEquals(expected, this, false)
+
+infix fun String?.`should be equal to json`(expected: String?) = shouldBeEqualToJson(expected)
+
+infix fun String?.shouldStrictlyBeEqualToJson(expected: String?) = JSONAssert.assertEquals(expected, this, true)
+
+infix fun String?.`should strictly be equal to json`(expected: String?) = shouldStrictlyBeEqualToJson(expected)
+
+infix fun String?.shouldNotStrictlyBeEqualToJson(expected: String?) = JSONAssert.assertNotEquals(expected, this, true)
+
+infix fun String?.`should not strictly be equal to json`(expected: String?) = shouldNotStrictlyBeEqualToJson(expected)
+
+infix fun String?.shouldNotBeEqualToJson(expected: String?) = JSONAssert.assertNotEquals(expected, this, false)
+
+infix fun String?.`should not be equal to json`(expected: String?) = shouldNotBeEqualToJson(expected)
diff --git a/api/test/utils/JsonAssertExtensions.kt b/api/test/utils/JsonAssertExtensions.kt
new file mode 100644
index 0000000..1ee2569
--- /dev/null
+++ b/api/test/utils/JsonAssertExtensions.kt
@@ -0,0 +1,23 @@
+package utils
+
+import org.json.JSONObject
+
+operator fun JSONObject.set(name: String, value: String) {
+    this.put(name, value)
+}
+
+operator fun JSONObject.set(name: String, value: Double) {
+    this.put(name, value)
+}
+
+operator fun JSONObject.set(name: String, value: Long) {
+    this.put(name, value)
+}
+
+operator fun JSONObject.set(name: String, value: Int) {
+    this.put(name, value)
+}
+
+operator fun JSONObject.set(name: String, value: Boolean) {
+    this.put(name, value)
+}
diff --git a/api/test/utils/KtorTestingExtensions.kt b/api/test/utils/KtorTestingExtensions.kt
new file mode 100644
index 0000000..7cad21a
--- /dev/null
+++ b/api/test/utils/KtorTestingExtensions.kt
@@ -0,0 +1,52 @@
+package utils
+
+import io.ktor.http.HttpHeaders
+import io.ktor.http.HttpMethod
+import io.ktor.server.testing.*
+import org.json.JSONObject
+
+
+fun TestApplicationRequest.json(block: (JSONObject) -> Unit) {
+    addHeader(HttpHeaders.ContentType, "application/json")
+    setBody(JSONObject().apply(block).toString())
+}
+
+fun TestApplicationRequest.setToken(token: String) {
+    addHeader(HttpHeaders.Authorization, "Bearer $token")
+}
+
+fun TestApplicationEngine.post(
+    uri: String,
+    setup: TestApplicationRequest.() -> Unit = {}
+): TestApplicationResponse = handleRequest {
+    this.uri = uri
+    this.method = HttpMethod.Post
+    setup()
+}.response
+
+fun TestApplicationEngine.get(
+    uri: String,
+    setup: TestApplicationRequest.() -> Unit = {}
+): TestApplicationResponse = handleRequest {
+    this.uri = uri
+    this.method = HttpMethod.Get
+    setup()
+}.response
+
+fun TestApplicationEngine.delete(
+    uri: String,
+    setup: TestApplicationRequest.() -> Unit = {}
+): TestApplicationResponse = handleRequest {
+    this.uri = uri
+    this.method = HttpMethod.Delete
+    setup()
+}.response
+
+fun TestApplicationEngine.put(
+    uri: String,
+    setup: TestApplicationRequest.() -> Unit = {}
+): TestApplicationResponse = handleRequest {
+    this.uri = uri
+    this.method = HttpMethod.Put
+    setup()
+}.response