diff --git a/api/src/resources/comment.rs b/api/src/resources/comment.rs
index bff3be87..d5ca1df5 100644
--- a/api/src/resources/comment.rs
+++ b/api/src/resources/comment.rs
@@ -873,7 +873,8 @@ pub struct NewEntityWithSpan {
     pub name: EntityName,
     pub formatted_value: String,
     pub span: NewEntitySpan,
-    pub field_id: FieldId,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub field_id: Option<FieldId>,
 }
 
 #[derive(Debug, Clone, PartialEq, Deserialize, Serialize, Eq)]
@@ -883,7 +884,8 @@ pub struct FieldId(pub String);
 pub struct NewEntityWithSpans {
     pub name: EntityName,
     pub formatted_value: String,
-    pub field_id: FieldId,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub field_id: Option<FieldId>,
     pub spans: Vec<NewEntitySpan>,
 }
 
@@ -900,7 +902,8 @@ pub struct Entity {
     pub name: EntityName,
     pub formatted_value: String,
     pub spans: Vec<EntitySpan>,
-    pub field_id: FieldId,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub field_id: Option<FieldId>,
 }
 
 #[derive(Debug, PartialEq, Clone, Deserialize, Serialize, Eq)]