diff --git a/src/backend/core/api/openapi.json b/src/backend/core/api/openapi.json
index d0b58518..b985f918 100644
--- a/src/backend/core/api/openapi.json
+++ b/src/backend/core/api/openapi.json
@@ -4696,6 +4696,7 @@
                     },
                     "draftBody": {
                         "type": "string",
+                        "nullable": true,
                         "readOnly": true
                     },
                     "attachments": {
diff --git a/src/backend/core/api/serializers.py b/src/backend/core/api/serializers.py
index 4fe86f11..c070faf9 100644
--- a/src/backend/core/api/serializers.py
+++ b/src/backend/core/api/serializers.py
@@ -532,7 +532,7 @@ class MessageSerializer(serializers.ModelSerializer):
         """Return the list of HTML body parts (JMAP style)."""
         return instance.get_parsed_field("htmlBody") or []
 
-    @extend_schema_field(serializers.CharField())
+    @extend_schema_field(serializers.CharField(allow_null=True))
     def get_draftBody(self, instance):  # pylint: disable=invalid-name
         """Return an arbitrary JSON object representing the draft body."""
         return (
diff --git a/src/frontend/src/features/api/gen/models/message.ts b/src/frontend/src/features/api/gen/models/message.ts
index 9078fd7a..005378ab 100644
--- a/src/frontend/src/features/api/gen/models/message.ts
+++ b/src/frontend/src/features/api/gen/models/message.ts
@@ -29,7 +29,8 @@ export interface Message {
   readonly updated_at: string;
   readonly htmlBody: readonly MessageHtmlBodyItem[];
   readonly textBody: readonly MessageTextBodyItem[];
-  readonly draftBody: string;
+  /** @nullable */
+  readonly draftBody: string | null;
   readonly attachments: readonly Attachment[];
   readonly sender: Contact;
   readonly to: readonly Contact[];
diff --git a/src/frontend/src/features/forms/components/message-form/index.tsx b/src/frontend/src/features/forms/components/message-form/index.tsx
index b4f9529b..92385c1b 100644
--- a/src/frontend/src/features/forms/components/message-form/index.tsx
+++ b/src/frontend/src/features/forms/components/message-form/index.tsx
@@ -145,7 +145,7 @@ export const MessageForm = ({
     }
 
     const formDefaultValues = useMemo(() => {
-        const [draftBody, draftDriveAttachments] = MailHelper.extractDriveAttachmentsFromDraft(draft?.draftBody);
+        const [draftBody, draftDriveAttachments] = MailHelper.extractDriveAttachmentsFromDraft(draft?.draftBody ?? '');
         return {
             from: defaultSenderId ?? '',
             to: draft?.to?.map(contact => contact.email) ?? recipients,