diff --git a/modules/core/src/main/scala/muffin/model/websocket/domain.scala b/modules/core/src/main/scala/muffin/model/websocket/domain.scala
index 8646db1..0120c73 100644
--- a/modules/core/src/main/scala/muffin/model/websocket/domain.scala
+++ b/modules/core/src/main/scala/muffin/model/websocket/domain.scala
@@ -1,5 +1,7 @@
 package muffin.model.websocket
 
+import scala.util._
+
 import muffin.model.Post
 
 object domain {
@@ -20,65 +22,77 @@ object domain {
       data: A
   )
 
-  enum EventType {
-    case Hello
-    case Posted
-    case AddedToTeam
-    case AuthenticationChallenge
-    case ChannelConverted
-    case ChannelCreated
-    case ChannelDeleted
-    case ChannelMemberUpdated
-    case ChannelUpdated
-    case ChannelViewed
-    case ConfigChanged
-    case DeleteTeam
-    case DirectAdded
-    case EmojiAdded
-    case EphemeralMessage
-    case GroupAdded
-    case LeaveTeam
-    case LicenseChanged
-    case MemberroleUpdated
-    case NewUser
-    case PluginDisabled
-    case PluginEnabled
-    case PluginStatusesChanged
-    case PostDeleted
-    case PostEdited
-    case PostUnread
-    case PreferenceChanged
-    case PreferencesChanged
-    case PreferencesDeleted
-    case ReactionAdded
-    case ReactionRemoved
-    case Response
-    case RoleUpdated
-    case StatusChange
-    case Typing
-    case UpdateTeam
-    case UserAdded
-    case UserRemoved
-    case UserRoleUpdated
-    case UserUpdated
-    case DialogOpened
-    case ThreadUpdated
-    case ThreadFollowChanged
-    case ThreadReadChanged
+  sealed trait EventType {
+    def repr: String
   }
 
   object EventType {
 
+    enum KnownEventType extends EventType {
+      case Hello
+      case Posted
+      case AddedToTeam
+      case AuthenticationChallenge
+      case ChannelConverted
+      case ChannelCreated
+      case ChannelDeleted
+      case ChannelMemberUpdated
+      case ChannelUpdated
+      case ChannelViewed
+      case ConfigChanged
+      case DeleteTeam
+      case DirectAdded
+      case EmojiAdded
+      case EphemeralMessage
+      case GroupAdded
+      case LeaveTeam
+      case LicenseChanged
+      case MemberroleUpdated
+      case NewUser
+      case PluginDisabled
+      case PluginEnabled
+      case PluginStatusesChanged
+      case PostDeleted
+      case PostEdited
+      case PostUnread
+      case PreferenceChanged
+      case PreferencesChanged
+      case PreferencesDeleted
+      case ReactionAdded
+      case ReactionRemoved
+      case Response
+      case RoleUpdated
+      case StatusChange
+      case Typing
+      case UpdateTeam
+      case UserAdded
+      case UserRemoved
+      case UserRoleUpdated
+      case UserUpdated
+      case DialogOpened
+      case ThreadUpdated
+      case ThreadFollowChanged
+      case ThreadReadChanged
+
+      def repr: String = this.toString
+    }
+
     def fromSnakeCase(s: String): EventType = {
       val tokens = s.split("_").toList.map(_.capitalize)
-      EventType.valueOf(
-        tokens.foldLeft(new StringBuilder(tokens.length)) {
-          (builder, token) => builder.addAll(token)
-        }
-          .toString()
-      )
+      Try(
+        KnownEventType.valueOf(
+          tokens.foldLeft(new StringBuilder(tokens.length)) {
+            (builder, token) => builder.addAll(token)
+          }
+            .result()
+        )
+      ) match {
+        case Success(tpe) => tpe
+        case Failure(_)   => CustomEventType(s)
+      }
     }
 
+    case class CustomEventType(repr: String) extends EventType
   }
 
   case class PostedEventData(channelName: String, channelType: ChannelType, senderName: String, post: Post)
diff --git a/modules/core/src/test/scala/muffin/api/ApiTest.scala b/modules/core/src/test/scala/muffin/api/ApiTest.scala
index cfebaa5..5a84b71 100644
--- a/modules/core/src/test/scala/muffin/api/ApiTest.scala
+++ b/modules/core/src/test/scala/muffin/api/ApiTest.scala
@@ -291,7 +291,7 @@ trait ApiTest[To[_], From[_]](integration: String, codecSupport: CodecSupport[To
           .websocket()
           .flatMap(
             _.addListener[domain.TestObject](
-              EventType.Hello,
+              EventType.KnownEventType.Hello,
               event => listenedEvent.complete(event).void
             )
               .connect()
@@ -310,7 +310,7 @@ trait ApiTest[To[_], From[_]](integration: String, codecSupport: CodecSupport[To
           .websocket()
           .flatMap(
             _.addListener[String](
-              EventType.Hello,
+              EventType.KnownEventType.Hello,
               event =>
                 listenedEvents.offer(domain.TestObject.default)
             )
@@ -325,7 +325,7 @@ trait ApiTest[To[_], From[_]](integration: String, codecSupport: CodecSupport[To
           .websocket()
           .flatMap(
             _.addListener[domain.TestObject](
-              EventType.Hello,
+              EventType.KnownEventType.Hello,
               event => listenedEvents.offer(event)
             )
               .connect()
@@ -347,7 +347,7 @@ trait ApiTest[To[_], From[_]](integration: String, codecSupport: CodecSupport[To
           .websocket()
           .flatMap(
             _.addListener[PostedEventData](
-              EventType.Posted,
+              EventType.KnownEventType.Posted,
               event => listenedEvent.complete(event).void
             )
               .connect()
diff --git a/modules/core/src/test/scala/muffin/model/websocket/EntityTypeParsingTest.scala b/modules/core/src/test/scala/muffin/model/websocket/EntityTypeParsingTest.scala
index e2b2b82..2b166ec 100644
--- a/modules/core/src/test/scala/muffin/model/websocket/EntityTypeParsingTest.scala
+++ b/modules/core/src/test/scala/muffin/model/websocket/EntityTypeParsingTest.scala
@@ -1,7 +1,6 @@
 package muffin.model.websocket
 
 import scala.concurrent.Future
-import scala.util.Try
 
 import muffin.api.ApiTestSupport
 import muffin.model.websocket.domain.*
@@ -61,16 +60,19 @@ class EntityTypeParsingTest() extends ApiTestSupport {
 
       val result: List[EventType] = rawTypes.map(EventType.fromSnakeCase)
 
-      Future.successful(assert(result.length == EventType.values.length))
+      Future.successful(assert(result.length == EventType.KnownEventType.values.length))
     }
-    Scenario(s"Parse from snake case, incorrect kebab case raw types $integration") {
-      val rawTypes = List(
-        "added-to-team"
-      )
+    Scenario(s"Parse from snake case custom types $integration") {
+      val rawType = "everything you want here"
 
-      val result = rawTypes.map(tpe => Try(EventType.fromSnakeCase(tpe)))
+      val result = EventType.fromSnakeCase(rawType)
 
-      Future.successful(assert(result.head.isFailure))
+      Future.successful(
+        result match {
+          case _: EventType.KnownEventType  => assert(false, "must be a custom type")
+          case EventType.CustomEventType(_) => assert(true)
+        }
+      )
     }
   }
 
diff --git a/modules/integration/circe-json-interop/src/test/scala/muffin/interop/json/circe/CirceApiTest.scala b/modules/integration/circe-json-interop/src/test/scala/muffin/interop/json/circe/CirceApiTest.scala
index 9c2443c..ecce515 100644
--- a/modules/integration/circe-json-interop/src/test/scala/muffin/interop/json/circe/CirceApiTest.scala
+++ b/modules/integration/circe-json-interop/src/test/scala/muffin/interop/json/circe/CirceApiTest.scala
@@ -63,10 +63,10 @@ class CirceApiTest extends ApiTest[Encoder, Decoder]("circe", codec) {
     .map(postingEvent =>
       List(
         Event(
-          EventType.Hello,
+          EventType.KnownEventType.Hello,
           RawJson.from(Encoder[domain.TestObject].apply(domain.TestObject.default).toString)
         ),
-        Event(EventType.Posted, RawJson.from(postingEvent))
+        Event(EventType.KnownEventType.Posted, RawJson.from(postingEvent))
       )
     )
 
diff --git a/modules/integration/zio-json-interop/src/test/scala/muffin/interop/json/zio/ZioApiTest.scala b/modules/integration/zio-json-interop/src/test/scala/muffin/interop/json/zio/ZioApiTest.scala
index 8b6af4b..b145682 100644
--- a/modules/integration/zio-json-interop/src/test/scala/muffin/interop/json/zio/ZioApiTest.scala
+++ b/modules/integration/zio-json-interop/src/test/scala/muffin/interop/json/zio/ZioApiTest.scala
@@ -62,10 +62,10 @@ class ZioApiTest extends ApiTest[JsonEncoder, JsonDecoder]("zio", codec) {
       private val events = loadResource("websockets/posting/postingWithFileIds.json").map(postingEvent =>
         List(
           Event(
-            EventType.Hello,
+            EventType.KnownEventType.Hello,
             RawJson.from(domain.TestObject.default.toJson)
           ),
-          Event(EventType.Posted, RawJson.from(postingEvent))
+          Event(EventType.KnownEventType.Posted, RawJson.from(postingEvent))
         )
       )
     }