diff --git a/skiplang/prelude/src/stdlib/serialization/JSON.sk b/skiplang/prelude/src/stdlib/serialization/JSON.sk
index 5ec8cd891..cf562a2ae 100644
--- a/skiplang/prelude/src/stdlib/serialization/JSON.sk
+++ b/skiplang/prelude/src/stdlib/serialization/JSON.sk
@@ -198,7 +198,7 @@ private fun indent(write: .String -> void, nspaces: Int): void {
 
 class KeyNotFoundError(key: .String) extends Serialization.SerializationError {
   fun getMessage(): .String {
-    "Key '" + this.key + "'not found";
+    "Key '" + this.key + "' not found";
   }
   fun toString(): .String {
     `KeyNotFoundError: ${this.getMessage()}`