diff --git a/frontend_tests/node_tests/submessage.js b/frontend_tests/node_tests/submessage.js
index 3a17f9b7c0..f9164a6fc1 100644
--- a/frontend_tests/node_tests/submessage.js
+++ b/frontend_tests/node_tests/submessage.js
@@ -67,7 +67,7 @@ run_test('handle_event', () => {
         msg_type: 'widget',
         sender_id: 99,
         message_id: message.id,
-        data: 'some_data',
+        content: '"some_data"',
     };
 
     var args;
diff --git a/static/js/server_events_dispatch.js b/static/js/server_events_dispatch.js
index 8b663fc168..9dacd1a011 100644
--- a/static/js/server_events_dispatch.js
+++ b/static/js/server_events_dispatch.js
@@ -258,7 +258,7 @@ exports.dispatch_normal_event = function dispatch_normal_event(event) {
             sender_id: event.sender_id,
             msg_type: event.msg_type,
             message_id: event.message_id,
-            data: event.data,
+            content: event.content,
         });
         break;
 
diff --git a/static/js/submessage.js b/static/js/submessage.js
index 4d0de9eb9d..4b39890d01 100644
--- a/static/js/submessage.js
+++ b/static/js/submessage.js
@@ -91,10 +91,19 @@ exports.handle_event = function (event) {
         return;
     }
 
+    var data;
+
+    try {
+        data = JSON.parse(event.content);
+    } catch (err) {
+        blueslip.error('server sent us invalid json in handle_event: ' + event.content);
+        return;
+    }
+
     widgetize.handle_event({
         sender_id: event.sender_id,
         message_id: event.message_id,
-        data: event.data,
+        data: data,
     });
 };
 
diff --git a/zerver/lib/actions.py b/zerver/lib/actions.py
index b501b21033..a7fc13b395 100644
--- a/zerver/lib/actions.py
+++ b/zerver/lib/actions.py
@@ -1440,7 +1440,6 @@ def do_add_submessage(sender_id: int,
                       message_id: int,
                       msg_type: str,
                       content: str,
-                      data: Any,
                       ) -> None:
     submessage = SubMessage(
         sender_id=sender_id,
@@ -1455,7 +1454,7 @@ def do_add_submessage(sender_id: int,
         msg_type=msg_type,
         message_id=message_id,
         sender_id=sender_id,
-        data=data,
+        content=content,
     )
     ums = UserMessage.objects.filter(message_id=message_id)
     target_user_ids = [um.user_profile_id for um in ums]
diff --git a/zerver/tests/test_events.py b/zerver/tests/test_events.py
index d5a79e42cd..d91217166a 100644
--- a/zerver/tests/test_events.py
+++ b/zerver/tests/test_events.py
@@ -874,7 +874,7 @@ class EventsRegisterTest(ZulipTestCase):
             ('message_id', check_int),
             ('sender_id', check_int),
             ('msg_type', check_string),
-            ('data', check_string),
+            ('content', check_string),
         ])
 
         cordelia = self.example_user('cordelia')
@@ -889,7 +889,6 @@ class EventsRegisterTest(ZulipTestCase):
                 message_id=message_id,
                 msg_type='whatever',
                 content='"stuff"',
-                data='stuff',
             ),
             state_change_expected=False,
         )
diff --git a/zerver/tests/test_submessage.py b/zerver/tests/test_submessage.py
index 86b95b42b7..fd4a6864ac 100644
--- a/zerver/tests/test_submessage.py
+++ b/zerver/tests/test_submessage.py
@@ -127,10 +127,7 @@ class TestBasics(ZulipTestCase):
 
         expected_data = dict(
             message_id=message_id,
-            data=dict(
-                name='alice',
-                salary=20,
-            ),
+            content=payload['content'],
             msg_type='whatever',
             sender_id=cordelia.id,
             type='submessage',
diff --git a/zerver/views/submessage.py b/zerver/views/submessage.py
index cdf420642e..7ea127bceb 100644
--- a/zerver/views/submessage.py
+++ b/zerver/views/submessage.py
@@ -32,7 +32,7 @@ def process_submessage(request: HttpRequest,
         return json_error(msg)
 
     try:
-        data = ujson.loads(content)
+        ujson.loads(content)
     except Exception:
         return json_error(_("Invalid json for submessage"))
 
@@ -41,6 +41,5 @@ def process_submessage(request: HttpRequest,
         message_id=message.id,
         msg_type=msg_type,
         content=content,
-        data=data,
     )
     return json_success()