diff --git a/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/KtorMeetacyEngine.kt b/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/KtorMeetacyEngine.kt
index f4073332..3caa46ec 100644
--- a/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/KtorMeetacyEngine.kt
+++ b/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/KtorMeetacyEngine.kt
@@ -23,6 +23,8 @@ import io.ktor.client.*
 import io.ktor.client.call.*
 import io.ktor.client.plugins.*
 import io.ktor.client.plugins.websocket.*
+import io.ktor.client.request.*
+import io.ktor.http.*
 import io.ktor.utils.io.errors.*
 import io.rsocket.kotlin.ktor.client.RSocketSupport
 import kotlinx.coroutines.CancellationException
@@ -43,6 +45,9 @@ public class KtorMeetacyEngine(
 
         install(WebSockets)
         install(RSocketSupport)
+        defaultRequest {
+            header(HttpHeaders.ContentType, ContentType.Application.Json.contentType)
+        }
     }
 
     private val auth = AuthEngine(baseUrl, this.httpClient)
diff --git a/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/requests/users/UsersEngine.kt b/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/requests/users/UsersEngine.kt
index e24ce0cb..08b00a3e 100644
--- a/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/requests/users/UsersEngine.kt
+++ b/api/api-ktor/src/commonMain/kotlin/app/meetacy/sdk/engine/ktor/requests/users/UsersEngine.kt
@@ -7,7 +7,6 @@ import app.meetacy.sdk.engine.requests.EditUserRequest
 import app.meetacy.sdk.engine.requests.GetMeRequest
 import app.meetacy.sdk.engine.requests.GetUserRequest
 import app.meetacy.sdk.engine.requests.UsernameAvailableRequest
-import app.meetacy.sdk.types.annotation.UnsafeConstructor
 import app.meetacy.sdk.types.optional.map
 import app.meetacy.sdk.types.serializable.file.FileIdSerializable
 import app.meetacy.sdk.types.serializable.file.serializable
@@ -88,7 +87,6 @@ internal class UsersEngine(
     )
 
 
-    @OptIn(UnsafeConstructor::class)
     suspend fun usernameAvailable(request: UsernameAvailableRequest): UsernameAvailableRequest.Response {
         val url = baseUrl / "username" / "available"
         val body = request.toBody()