diff --git a/beat/web/experiments/serializers.py b/beat/web/experiments/serializers.py
index d47bb6f8300e91f44cb95b2759d2d8b6b12a5c95..84cb3fe2202b5889969769b4f2a0c5e13221444c 100755
--- a/beat/web/experiments/serializers.py
+++ b/beat/web/experiments/serializers.py
@@ -54,7 +54,7 @@ from .models import Experiment, Block
 class ExperimentCreationSerializer(serializers.ModelSerializer):
     declaration = beat_fields.JSONField()
     description = serializers.CharField(required=False, allow_blank=True)
-    fork_of = beat_fields.JSONField(required=False)
+    fork_of = serializers.CharField(required=False)
     toolchain = serializers.CharField()
 
     class Meta: