diff --git a/pyinfra/default_objects.py b/pyinfra/default_objects.py
index 3281a86..6048829 100644
--- a/pyinfra/default_objects.py
+++ b/pyinfra/default_objects.py
@@ -88,7 +88,7 @@ class Callback:
             raise AnalysisFailure from err
 
     def __call__(self, body: dict):
-        operation = body.get("operations", "submit")
+        operation = body.get("operation", "submit")
         endpoint = self.__make_endpoint(operation)
         pipeline = self.__get_pipeline(endpoint)
 
diff --git a/pyinfra/server/server.py b/pyinfra/server/server.py
index 8f6e4ef..ec001c3 100644
--- a/pyinfra/server/server.py
+++ b/pyinfra/server/server.py
@@ -21,6 +21,12 @@ def __set_up_processing_server(queued_stream_function: QueuedStreamFunction):
         resp.status_code = 200
         return resp
 
+    @app.route("/health", methods=["GET"])
+    def healthy():
+        resp = jsonify("OK")
+        resp.status_code = 200
+        return resp
+
     @app.route("/submit", methods=["POST", "PATCH"])
     def submit():
         return processor.push(request)
diff --git a/pyinfra/visitor.py b/pyinfra/visitor.py
index 98857f3..61ffbd1 100644
--- a/pyinfra/visitor.py
+++ b/pyinfra/visitor.py
@@ -6,7 +6,7 @@ import logging
 import time
 from collections import deque
 from operator import itemgetter
-from typing import Callable, Iterable
+from typing import Callable
 
 from funcy import omit
 from more_itertools import peekable
@@ -105,11 +105,6 @@ class IdentifierDispatchCallback(DispatchCallback):
 
         return identifier != self.identifier
 
-    # def data_is_non_empty(self, data):
-    #
-    #     if isinstance(data, str):
-    #         self.put_object(data, metadata)
-
     def __call__(self, metadata):
 
         return self.has_new_identifier(metadata)
@@ -200,12 +195,17 @@ class QueueVisitor:
             return {"data": data, "metadata": {}}
 
         try:
-            data = json.loads(data.decode())
-        except json.JSONDecodeError:  # case 1 fallback
-            return wrap(data.decode())
+            data = data.decode()
+            try:
+                data = json.loads(data)
+            except json.JSONDecodeError:  # case 1 fallback
+                return wrap(data)
+        except Exception:
+            return wrap(data)
 
         if not isinstance(data, dict):  # case 1
             return wrap(string_to_bytes(data))
+
         else:  # case 2
             validate(data)
             data["data"] = string_to_bytes(data["data"])
diff --git a/scripts/mock_client.py b/scripts/mock_client.py
index 0a97e03..e8ad0fa 100644
--- a/scripts/mock_client.py
+++ b/scripts/mock_client.py
@@ -54,7 +54,7 @@ def build_message_bodies(analyse_container_type, bucket_name):
         return message_dict
 
     storage = get_s3_storage()
-    for bucket_name, pdf_name in storage.get_all_object_names(bucket_name):
+    for pdf_name in storage.get_all_object_names(bucket_name):
         if "pdf" not in pdf_name:
             continue
         file_id = pdf_name.split(".")[0]
diff --git a/test/integration_tests/serve_test.py b/test/integration_tests/serve_test.py
index 246e18c..4c79cc1 100644
--- a/test/integration_tests/serve_test.py
+++ b/test/integration_tests/serve_test.py
@@ -153,3 +153,5 @@ def test_serving(
     uploaded_files = starmap(storage.get_object, zip(repeat(bucket_name), names_of_uploaded_files))
     outputs = sorted(chain(*map(decode, uploaded_files)), key=itemgetter(0))
     assert outputs == targets
+
+    storage.clear_bucket(bucket_name)