diff --git a/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/ServiceType.scala b/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/ServiceType.scala
new file mode 100644
index 0000000000..eaaa0344d8
--- /dev/null
+++ b/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/ServiceType.scala
@@ -0,0 +1,27 @@
+package io.iohk.atala.mercury.protocol.invitation
+import cats.implicits._
+import io.circe.syntax._
+import io.circe.generic.semiauto._
+import io.circe.generic.semiauto.{deriveDecoder, deriveEncoder}
+import io.circe.{Decoder, Encoder, HCursor, Json}
+
+sealed trait ServiceType
+
+/** Service block
+  * @see
+  *   https://github.com/hyperledger/aries-rfcs/tree/main/features/0434-outofband
+  * @param id
+  * @param `type`
+  * @param recipientKeys
+  * @param routingKeys
+  * @param serviceEndpoint
+  */
+case class Service(
+    id: String,
+    `type`: String,
+    recipientKeys: Seq[String],
+    routingKeys: Option[Seq[String]],
+    serviceEndpoint: String,
+) extends ServiceType
+
+case class Did(did: String) extends ServiceType
diff --git a/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/package.scala b/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/package.scala
new file mode 100644
index 0000000000..a1c1693bb2
--- /dev/null
+++ b/mercury/prism-mediator/protocol-invitation/src/main/scala/io/iohk/atala/mercury/protocol/invitation/package.scala
@@ -0,0 +1,11 @@
+package io.iohk.atala.mercury.protocol
+
+import java.util.UUID
+
+package object invitation {
+
+  /** provides new msg id
+    * @return
+    */
+  def getNewMsgId: String = UUID.randomUUID().toString
+}