diff --git a/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala b/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
index 81dfa809..34020d44 100644
--- a/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
+++ b/core/src/main/scala/sttp/model/sse/ServerSentEvent.scala
@@ -3,11 +3,11 @@ package sttp.model.sse
 import scala.util.Try
 
 case class ServerSentEvent(
-    data: Option[String] = None,
-    eventType: Option[String] = None,
-    id: Option[String] = None,
-    retry: Option[Int] = None
-)
+                            data: Option[String] = None,
+                            eventType: Option[String] = None,
+                            id: Option[String] = None,
+                            retry: Option[Int] = None
+                          )
 
 object ServerSentEvent {
   // https://html.spec.whatwg.org/multipage/server-sent-events.html
@@ -24,10 +24,18 @@ object ServerSentEvent {
     }
   }
 
+  def composeSSE(sse: ServerSentEvent): String = {
+    val data = sse.data.map(_.split("\n")).map(_.map(line => Some(s"data: $line"))).getOrElse(Array.empty[Option[String]])
+    val event = sse.eventType.map(event => s"event: $event")
+    val id = sse.id.map(id => s"id: $id")
+    val retry = sse.retry.map(retryCount => s"retry: $retryCount")
+    (data :+ event :+ id :+ retry).flatten.mkString("\n")
+  }
+
   private def combineData(event: ServerSentEvent, newData: String): ServerSentEvent = {
     event match {
-      case e @ ServerSentEvent(Some(oldData), _, _, _) => e.copy(data = Some(s"$oldData\n$newData"))
-      case e @ ServerSentEvent(None, _, _, _)          => e.copy(data = Some(newData))
+      case e@ServerSentEvent(Some(oldData), _, _, _) => e.copy(data = Some(s"$oldData\n$newData"))
+      case e@ServerSentEvent(None, _, _, _) => e.copy(data = Some(newData))
     }
   }
 
diff --git a/core/src/test/scala/sttp/model/sse/ServerSentEventTest.scala b/core/src/test/scala/sttp/model/sse/ServerSentEventTest.scala
index 6028dba2..255fcba4 100644
--- a/core/src/test/scala/sttp/model/sse/ServerSentEventTest.scala
+++ b/core/src/test/scala/sttp/model/sse/ServerSentEventTest.scala
@@ -28,4 +28,38 @@ class ServerSentEventTest extends AnyFlatSpec with Matchers {
       ServerSentEvent.parse(lines) shouldBe expected
     }
   }
+
+
+  "composeSSE" should "successfully serialise Server Sent Event with all fields set" in {
+    val sse = ServerSentEvent(Some("data"), Some("event"), Some("id1"), Some(10))
+    ServerSentEvent.composeSSE(sse) shouldBe
+      s"""data: data
+         |event: event
+         |id: id1
+         |retry: 10""".stripMargin
+  }
+
+  "composeSSE" should "omit fields that are not set" in {
+    val sse = ServerSentEvent(Some("data"), None, Some("id1"), None)
+    ServerSentEvent.composeSSE(sse) shouldBe
+      s"""data: data
+         |id: id1""".stripMargin
+  }
+
+  "composeSSE" should "successfully serialise multiline data event" in {
+    val sse = ServerSentEvent(
+      Some(
+        """some data info 1
+          |some data info 2
+          |some data info 3""".stripMargin),
+      None,
+      None,
+      None
+    )
+
+    ServerSentEvent.composeSSE(sse) shouldBe
+      s"""data: some data info 1
+         |data: some data info 2
+         |data: some data info 3""".stripMargin
+  }
 }