diff --git a/src/proto/flwr/proto/driver.proto b/src/proto/flwr/proto/driver.proto
index 1cfb77135d5a..1caaad88a0da 100644
--- a/src/proto/flwr/proto/driver.proto
+++ b/src/proto/flwr/proto/driver.proto
@@ -36,10 +36,10 @@ service Driver {
 
 // CreateWorkload
 message CreateWorkloadRequest {}
-message CreateWorkloadResponse { string workload_id = 1; }
+message CreateWorkloadResponse { uint64 workload_id = 1; }
 
 // GetNodes messages
-message GetNodesRequest { string workload_id = 1; }
+message GetNodesRequest { uint64 workload_id = 1; }
 message GetNodesResponse { repeated Node nodes = 1; }
 
 // PushTaskIns messages
diff --git a/src/proto/flwr/proto/task.proto b/src/proto/flwr/proto/task.proto
index 29e07641bb1c..d87fb39c2637 100644
--- a/src/proto/flwr/proto/task.proto
+++ b/src/proto/flwr/proto/task.proto
@@ -36,14 +36,14 @@ message Task {
 message TaskIns {
   string task_id = 1;
   string group_id = 2;
-  string workload_id = 3;
+  uint64 workload_id = 3;
   Task task = 4;
 }
 
 message TaskRes {
   string task_id = 1;
   string group_id = 2;
-  string workload_id = 3;
+  uint64 workload_id = 3;
   Task task = 4;
 }
 
diff --git a/src/py/flwr/client/grpc_client/connection.py b/src/py/flwr/client/grpc_client/connection.py
index eda869d3a326..cc64ec9a268a 100644
--- a/src/py/flwr/client/grpc_client/connection.py
+++ b/src/py/flwr/client/grpc_client/connection.py
@@ -117,7 +117,7 @@ def receive() -> TaskIns:
         return TaskIns(
             task_id=str(uuid.uuid4()),
             group_id="",
-            workload_id="",
+            workload_id=0,
             task=Task(
                 producer=Node(node_id=0, anonymous=True),
                 consumer=Node(node_id=0, anonymous=True),
diff --git a/src/py/flwr/client/message_handler/message_handler.py b/src/py/flwr/client/message_handler/message_handler.py
index 9b26a9bd5ca0..f50923450f62 100644
--- a/src/py/flwr/client/message_handler/message_handler.py
+++ b/src/py/flwr/client/message_handler/message_handler.py
@@ -76,7 +76,7 @@ def handle(client_fn: ClientFn, task_ins: TaskIns) -> Tuple[TaskRes, int, bool]:
             task_res = TaskRes(
                 task_id="",
                 group_id="",
-                workload_id="",
+                workload_id=0,
                 task=Task(
                     ancestry=[],
                     sa=SecureAggregation(named_values=serde.named_values_to_proto(res)),
diff --git a/src/py/flwr/client/message_handler/message_handler_test.py b/src/py/flwr/client/message_handler/message_handler_test.py
index 31cbb00edf63..1fc2269ad75d 100644
--- a/src/py/flwr/client/message_handler/message_handler_test.py
+++ b/src/py/flwr/client/message_handler/message_handler_test.py
@@ -120,7 +120,7 @@ def test_client_without_get_properties() -> None:
     task_ins: TaskIns = TaskIns(
         task_id=str(uuid.uuid4()),
         group_id="",
-        workload_id="",
+        workload_id=0,
         task=Task(
             producer=Node(node_id=0, anonymous=True),
             consumer=Node(node_id=0, anonymous=True),
@@ -146,7 +146,7 @@ def test_client_without_get_properties() -> None:
         TaskRes(
             task_id=str(uuid.uuid4()),
             group_id="",
-            workload_id="",
+            workload_id=0,
         )
     )
     # pylint: disable=no-member
@@ -183,7 +183,7 @@ def test_client_with_get_properties() -> None:
     task_ins = TaskIns(
         task_id=str(uuid.uuid4()),
         group_id="",
-        workload_id="",
+        workload_id=0,
         task=Task(
             producer=Node(node_id=0, anonymous=True),
             consumer=Node(node_id=0, anonymous=True),
@@ -209,7 +209,7 @@ def test_client_with_get_properties() -> None:
         TaskRes(
             task_id=str(uuid.uuid4()),
             group_id="",
-            workload_id="",
+            workload_id=0,
         )
     )
     # pylint: disable=no-member
diff --git a/src/py/flwr/client/message_handler/task_handler.py b/src/py/flwr/client/message_handler/task_handler.py
index 03688c52ac8f..b48c7433c1da 100644
--- a/src/py/flwr/client/message_handler/task_handler.py
+++ b/src/py/flwr/client/message_handler/task_handler.py
@@ -129,7 +129,7 @@ def wrap_client_message_in_task_res(client_message: ClientMessage) -> TaskRes:
     return TaskRes(
         task_id="",
         group_id="",
-        workload_id="",
+        workload_id=0,
         task=Task(ancestry=[], legacy_client_message=client_message),
     )
 
diff --git a/src/py/flwr/client/message_handler/task_handler_test.py b/src/py/flwr/client/message_handler/task_handler_test.py
index 347b9ad32c4b..e1b7fac69d24 100644
--- a/src/py/flwr/client/message_handler/task_handler_test.py
+++ b/src/py/flwr/client/message_handler/task_handler_test.py
@@ -92,7 +92,7 @@ def test_validate_task_res() -> None:
     assert not validate_task_res(task_res)
 
     task_res.Clear()
-    task_res.workload_id = "123"
+    task_res.workload_id = 61016
     assert not validate_task_res(task_res)
 
     task_res.Clear()
diff --git a/src/py/flwr/driver/app_test.py b/src/py/flwr/driver/app_test.py
index 792bd84b6106..4fcd924f8432 100644
--- a/src/py/flwr/driver/app_test.py
+++ b/src/py/flwr/driver/app_test.py
@@ -43,7 +43,7 @@ def test_simple_client_manager_update(self) -> None:
         ]
         driver = MagicMock()
         driver.stub = "driver stub"
-        driver.create_workload.return_value = CreateWorkloadResponse(workload_id="1")
+        driver.create_workload.return_value = CreateWorkloadResponse(workload_id=1)
         driver.get_nodes.return_value = GetNodesResponse(nodes=expected_nodes)
         client_manager = SimpleClientManager()
         lock = threading.Lock()
diff --git a/src/py/flwr/driver/driver_client_proxy.py b/src/py/flwr/driver/driver_client_proxy.py
index cd5d36cafdd7..deb472458a15 100644
--- a/src/py/flwr/driver/driver_client_proxy.py
+++ b/src/py/flwr/driver/driver_client_proxy.py
@@ -31,7 +31,7 @@
 class DriverClientProxy(ClientProxy):
     """Flower client proxy which delegates work using the Driver API."""
 
-    def __init__(self, node_id: int, driver: Driver, anonymous: bool, workload_id: str):
+    def __init__(self, node_id: int, driver: Driver, anonymous: bool, workload_id: int):
         super().__init__(str(node_id))
         self.node_id = node_id
         self.driver = driver
diff --git a/src/py/flwr/driver/driver_client_proxy_test.py b/src/py/flwr/driver/driver_client_proxy_test.py
index fa2a29e88687..f413b8d8d99d 100644
--- a/src/py/flwr/driver/driver_client_proxy_test.py
+++ b/src/py/flwr/driver/driver_client_proxy_test.py
@@ -52,7 +52,7 @@ def test_get_properties(self) -> None:
                 task_pb2.TaskRes(
                     task_id="554bd3c8-8474-4b93-a7db-c7bec1bf0012",
                     group_id="",
-                    workload_id="",
+                    workload_id=0,
                     task=task_pb2.Task(
                         legacy_client_message=ClientMessage(
                             get_properties_res=ClientMessage.GetPropertiesRes(
@@ -64,7 +64,7 @@ def test_get_properties(self) -> None:
             ]
         )
         client = DriverClientProxy(
-            node_id=1, driver=self.driver, anonymous=True, workload_id=""
+            node_id=1, driver=self.driver, anonymous=True, workload_id=0
         )
         request_properties: Config = {"tensor_type": "str"}
         ins: flwr.common.GetPropertiesIns = flwr.common.GetPropertiesIns(
@@ -88,7 +88,7 @@ def test_get_parameters(self) -> None:
                 task_pb2.TaskRes(
                     task_id="554bd3c8-8474-4b93-a7db-c7bec1bf0012",
                     group_id="",
-                    workload_id="",
+                    workload_id=0,
                     task=task_pb2.Task(
                         legacy_client_message=ClientMessage(
                             get_parameters_res=ClientMessage.GetParametersRes(
@@ -100,7 +100,7 @@ def test_get_parameters(self) -> None:
             ]
         )
         client = DriverClientProxy(
-            node_id=1, driver=self.driver, anonymous=True, workload_id=""
+            node_id=1, driver=self.driver, anonymous=True, workload_id=0
         )
         get_parameters_ins = GetParametersIns(config={})
 
@@ -123,7 +123,7 @@ def test_fit(self) -> None:
                 task_pb2.TaskRes(
                     task_id="554bd3c8-8474-4b93-a7db-c7bec1bf0012",
                     group_id="",
-                    workload_id="",
+                    workload_id=0,
                     task=task_pb2.Task(
                         legacy_client_message=ClientMessage(
                             fit_res=ClientMessage.FitRes(
@@ -136,7 +136,7 @@ def test_fit(self) -> None:
             ]
         )
         client = DriverClientProxy(
-            node_id=1, driver=self.driver, anonymous=True, workload_id=""
+            node_id=1, driver=self.driver, anonymous=True, workload_id=0
         )
         parameters = flwr.common.ndarrays_to_parameters([np.ones((2, 2))])
         ins: flwr.common.FitIns = flwr.common.FitIns(parameters, {})
@@ -160,7 +160,7 @@ def test_evaluate(self) -> None:
                 task_pb2.TaskRes(
                     task_id="554bd3c8-8474-4b93-a7db-c7bec1bf0012",
                     group_id="",
-                    workload_id="",
+                    workload_id=0,
                     task=task_pb2.Task(
                         legacy_client_message=ClientMessage(
                             evaluate_res=ClientMessage.EvaluateRes(
@@ -172,7 +172,7 @@ def test_evaluate(self) -> None:
             ]
         )
         client = DriverClientProxy(
-            node_id=1, driver=self.driver, anonymous=True, workload_id=""
+            node_id=1, driver=self.driver, anonymous=True, workload_id=0
         )
         parameters = flwr.common.Parameters(tensors=[], tensor_type="np")
         evaluate_ins: flwr.common.EvaluateIns = flwr.common.EvaluateIns(parameters, {})
diff --git a/src/py/flwr/proto/driver_pb2.py b/src/py/flwr/proto/driver_pb2.py
index c18d9c593c28..6ac066d7eab3 100644
--- a/src/py/flwr/proto/driver_pb2.py
+++ b/src/py/flwr/proto/driver_pb2.py
@@ -16,7 +16,7 @@
 from flwr.proto import task_pb2 as flwr_dot_proto_dot_task__pb2
 
 
-DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x17\x66lwr/proto/driver.proto\x12\nflwr.proto\x1a\x15\x66lwr/proto/node.proto\x1a\x15\x66lwr/proto/task.proto\"\x17\n\x15\x43reateWorkloadRequest\"-\n\x16\x43reateWorkloadResponse\x12\x13\n\x0bworkload_id\x18\x01 \x01(\t\"&\n\x0fGetNodesRequest\x12\x13\n\x0bworkload_id\x18\x01 \x01(\t\"3\n\x10GetNodesResponse\x12\x1f\n\x05nodes\x18\x01 \x03(\x0b\x32\x10.flwr.proto.Node\"@\n\x12PushTaskInsRequest\x12*\n\rtask_ins_list\x18\x01 \x03(\x0b\x32\x13.flwr.proto.TaskIns\"\'\n\x13PushTaskInsResponse\x12\x10\n\x08task_ids\x18\x02 \x03(\t\"F\n\x12PullTaskResRequest\x12\x1e\n\x04node\x18\x01 \x01(\x0b\x32\x10.flwr.proto.Node\x12\x10\n\x08task_ids\x18\x02 \x03(\t\"A\n\x13PullTaskResResponse\x12*\n\rtask_res_list\x18\x01 \x03(\x0b\x32\x13.flwr.proto.TaskRes2\xd0\x02\n\x06\x44river\x12Y\n\x0e\x43reateWorkload\x12!.flwr.proto.CreateWorkloadRequest\x1a\".flwr.proto.CreateWorkloadResponse\"\x00\x12G\n\x08GetNodes\x12\x1b.flwr.proto.GetNodesRequest\x1a\x1c.flwr.proto.GetNodesResponse\"\x00\x12P\n\x0bPushTaskIns\x12\x1e.flwr.proto.PushTaskInsRequest\x1a\x1f.flwr.proto.PushTaskInsResponse\"\x00\x12P\n\x0bPullTaskRes\x12\x1e.flwr.proto.PullTaskResRequest\x1a\x1f.flwr.proto.PullTaskResResponse\"\x00\x62\x06proto3')
+DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x17\x66lwr/proto/driver.proto\x12\nflwr.proto\x1a\x15\x66lwr/proto/node.proto\x1a\x15\x66lwr/proto/task.proto\"\x17\n\x15\x43reateWorkloadRequest\"-\n\x16\x43reateWorkloadResponse\x12\x13\n\x0bworkload_id\x18\x01 \x01(\x04\"&\n\x0fGetNodesRequest\x12\x13\n\x0bworkload_id\x18\x01 \x01(\x04\"3\n\x10GetNodesResponse\x12\x1f\n\x05nodes\x18\x01 \x03(\x0b\x32\x10.flwr.proto.Node\"@\n\x12PushTaskInsRequest\x12*\n\rtask_ins_list\x18\x01 \x03(\x0b\x32\x13.flwr.proto.TaskIns\"\'\n\x13PushTaskInsResponse\x12\x10\n\x08task_ids\x18\x02 \x03(\t\"F\n\x12PullTaskResRequest\x12\x1e\n\x04node\x18\x01 \x01(\x0b\x32\x10.flwr.proto.Node\x12\x10\n\x08task_ids\x18\x02 \x03(\t\"A\n\x13PullTaskResResponse\x12*\n\rtask_res_list\x18\x01 \x03(\x0b\x32\x13.flwr.proto.TaskRes2\xd0\x02\n\x06\x44river\x12Y\n\x0e\x43reateWorkload\x12!.flwr.proto.CreateWorkloadRequest\x1a\".flwr.proto.CreateWorkloadResponse\"\x00\x12G\n\x08GetNodes\x12\x1b.flwr.proto.GetNodesRequest\x1a\x1c.flwr.proto.GetNodesResponse\"\x00\x12P\n\x0bPushTaskIns\x12\x1e.flwr.proto.PushTaskInsRequest\x1a\x1f.flwr.proto.PushTaskInsResponse\"\x00\x12P\n\x0bPullTaskRes\x12\x1e.flwr.proto.PullTaskResRequest\x1a\x1f.flwr.proto.PullTaskResResponse\"\x00\x62\x06proto3')
 
 
 
diff --git a/src/py/flwr/proto/driver_pb2.pyi b/src/py/flwr/proto/driver_pb2.pyi
index 486bddb0f76f..8b940972cb6d 100644
--- a/src/py/flwr/proto/driver_pb2.pyi
+++ b/src/py/flwr/proto/driver_pb2.pyi
@@ -23,10 +23,10 @@ global___CreateWorkloadRequest = CreateWorkloadRequest
 class CreateWorkloadResponse(google.protobuf.message.Message):
     DESCRIPTOR: google.protobuf.descriptor.Descriptor
     WORKLOAD_ID_FIELD_NUMBER: builtins.int
-    workload_id: typing.Text
+    workload_id: builtins.int
     def __init__(self,
         *,
-        workload_id: typing.Text = ...,
+        workload_id: builtins.int = ...,
         ) -> None: ...
     def ClearField(self, field_name: typing_extensions.Literal["workload_id",b"workload_id"]) -> None: ...
 global___CreateWorkloadResponse = CreateWorkloadResponse
@@ -35,10 +35,10 @@ class GetNodesRequest(google.protobuf.message.Message):
     """GetNodes messages"""
     DESCRIPTOR: google.protobuf.descriptor.Descriptor
     WORKLOAD_ID_FIELD_NUMBER: builtins.int
-    workload_id: typing.Text
+    workload_id: builtins.int
     def __init__(self,
         *,
-        workload_id: typing.Text = ...,
+        workload_id: builtins.int = ...,
         ) -> None: ...
     def ClearField(self, field_name: typing_extensions.Literal["workload_id",b"workload_id"]) -> None: ...
 global___GetNodesRequest = GetNodesRequest
diff --git a/src/py/flwr/proto/task_pb2.py b/src/py/flwr/proto/task_pb2.py
index 42d3952f61df..69bad48d0d37 100644
--- a/src/py/flwr/proto/task_pb2.py
+++ b/src/py/flwr/proto/task_pb2.py
@@ -16,7 +16,7 @@
 from flwr.proto import transport_pb2 as flwr_dot_proto_dot_transport__pb2
 
 
-DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x15\x66lwr/proto/task.proto\x12\nflwr.proto\x1a\x15\x66lwr/proto/node.proto\x1a\x1a\x66lwr/proto/transport.proto\"\xbe\x02\n\x04Task\x12\"\n\x08producer\x18\x01 \x01(\x0b\x32\x10.flwr.proto.Node\x12\"\n\x08\x63onsumer\x18\x02 \x01(\x0b\x32\x10.flwr.proto.Node\x12\x12\n\ncreated_at\x18\x03 \x01(\t\x12\x14\n\x0c\x64\x65livered_at\x18\x04 \x01(\t\x12\x0b\n\x03ttl\x18\x05 \x01(\t\x12\x10\n\x08\x61ncestry\x18\x06 \x03(\t\x12)\n\x02sa\x18\x07 \x01(\x0b\x32\x1d.flwr.proto.SecureAggregation\x12<\n\x15legacy_server_message\x18\x65 \x01(\x0b\x32\x19.flwr.proto.ServerMessageB\x02\x18\x01\x12<\n\x15legacy_client_message\x18\x66 \x01(\x0b\x32\x19.flwr.proto.ClientMessageB\x02\x18\x01\"a\n\x07TaskIns\x12\x0f\n\x07task_id\x18\x01 \x01(\t\x12\x10\n\x08group_id\x18\x02 \x01(\t\x12\x13\n\x0bworkload_id\x18\x03 \x01(\t\x12\x1e\n\x04task\x18\x04 \x01(\x0b\x32\x10.flwr.proto.Task\"a\n\x07TaskRes\x12\x0f\n\x07task_id\x18\x01 \x01(\t\x12\x10\n\x08group_id\x18\x02 \x01(\t\x12\x13\n\x0bworkload_id\x18\x03 \x01(\t\x12\x1e\n\x04task\x18\x04 \x01(\x0b\x32\x10.flwr.proto.Task\"\xf3\x03\n\x05Value\x12\x10\n\x06\x64ouble\x18\x01 \x01(\x01H\x00\x12\x10\n\x06sint64\x18\x02 \x01(\x12H\x00\x12\x0e\n\x04\x62ool\x18\x03 \x01(\x08H\x00\x12\x10\n\x06string\x18\x04 \x01(\tH\x00\x12\x0f\n\x05\x62ytes\x18\x05 \x01(\x0cH\x00\x12\x33\n\x0b\x64ouble_list\x18\x15 \x01(\x0b\x32\x1c.flwr.proto.Value.DoubleListH\x00\x12\x33\n\x0bsint64_list\x18\x16 \x01(\x0b\x32\x1c.flwr.proto.Value.Sint64ListH\x00\x12/\n\tbool_list\x18\x17 \x01(\x0b\x32\x1a.flwr.proto.Value.BoolListH\x00\x12\x33\n\x0bstring_list\x18\x18 \x01(\x0b\x32\x1c.flwr.proto.Value.StringListH\x00\x12\x31\n\nbytes_list\x18\x19 \x01(\x0b\x32\x1b.flwr.proto.Value.BytesListH\x00\x1a\x1a\n\nDoubleList\x12\x0c\n\x04vals\x18\x01 \x03(\x01\x1a\x1a\n\nSint64List\x12\x0c\n\x04vals\x18\x01 \x03(\x12\x1a\x18\n\x08\x42oolList\x12\x0c\n\x04vals\x18\x01 \x03(\x08\x1a\x1a\n\nStringList\x12\x0c\n\x04vals\x18\x01 \x03(\t\x1a\x19\n\tBytesList\x12\x0c\n\x04vals\x18\x01 \x03(\x0c\x42\x07\n\x05value\"\xa0\x01\n\x11SecureAggregation\x12\x44\n\x0cnamed_values\x18\x01 \x03(\x0b\x32..flwr.proto.SecureAggregation.NamedValuesEntry\x1a\x45\n\x10NamedValuesEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12 \n\x05value\x18\x02 \x01(\x0b\x32\x11.flwr.proto.Value:\x02\x38\x01\x62\x06proto3')
+DESCRIPTOR = _descriptor_pool.Default().AddSerializedFile(b'\n\x15\x66lwr/proto/task.proto\x12\nflwr.proto\x1a\x15\x66lwr/proto/node.proto\x1a\x1a\x66lwr/proto/transport.proto\"\xbe\x02\n\x04Task\x12\"\n\x08producer\x18\x01 \x01(\x0b\x32\x10.flwr.proto.Node\x12\"\n\x08\x63onsumer\x18\x02 \x01(\x0b\x32\x10.flwr.proto.Node\x12\x12\n\ncreated_at\x18\x03 \x01(\t\x12\x14\n\x0c\x64\x65livered_at\x18\x04 \x01(\t\x12\x0b\n\x03ttl\x18\x05 \x01(\t\x12\x10\n\x08\x61ncestry\x18\x06 \x03(\t\x12)\n\x02sa\x18\x07 \x01(\x0b\x32\x1d.flwr.proto.SecureAggregation\x12<\n\x15legacy_server_message\x18\x65 \x01(\x0b\x32\x19.flwr.proto.ServerMessageB\x02\x18\x01\x12<\n\x15legacy_client_message\x18\x66 \x01(\x0b\x32\x19.flwr.proto.ClientMessageB\x02\x18\x01\"a\n\x07TaskIns\x12\x0f\n\x07task_id\x18\x01 \x01(\t\x12\x10\n\x08group_id\x18\x02 \x01(\t\x12\x13\n\x0bworkload_id\x18\x03 \x01(\x04\x12\x1e\n\x04task\x18\x04 \x01(\x0b\x32\x10.flwr.proto.Task\"a\n\x07TaskRes\x12\x0f\n\x07task_id\x18\x01 \x01(\t\x12\x10\n\x08group_id\x18\x02 \x01(\t\x12\x13\n\x0bworkload_id\x18\x03 \x01(\x04\x12\x1e\n\x04task\x18\x04 \x01(\x0b\x32\x10.flwr.proto.Task\"\xf3\x03\n\x05Value\x12\x10\n\x06\x64ouble\x18\x01 \x01(\x01H\x00\x12\x10\n\x06sint64\x18\x02 \x01(\x12H\x00\x12\x0e\n\x04\x62ool\x18\x03 \x01(\x08H\x00\x12\x10\n\x06string\x18\x04 \x01(\tH\x00\x12\x0f\n\x05\x62ytes\x18\x05 \x01(\x0cH\x00\x12\x33\n\x0b\x64ouble_list\x18\x15 \x01(\x0b\x32\x1c.flwr.proto.Value.DoubleListH\x00\x12\x33\n\x0bsint64_list\x18\x16 \x01(\x0b\x32\x1c.flwr.proto.Value.Sint64ListH\x00\x12/\n\tbool_list\x18\x17 \x01(\x0b\x32\x1a.flwr.proto.Value.BoolListH\x00\x12\x33\n\x0bstring_list\x18\x18 \x01(\x0b\x32\x1c.flwr.proto.Value.StringListH\x00\x12\x31\n\nbytes_list\x18\x19 \x01(\x0b\x32\x1b.flwr.proto.Value.BytesListH\x00\x1a\x1a\n\nDoubleList\x12\x0c\n\x04vals\x18\x01 \x03(\x01\x1a\x1a\n\nSint64List\x12\x0c\n\x04vals\x18\x01 \x03(\x12\x1a\x18\n\x08\x42oolList\x12\x0c\n\x04vals\x18\x01 \x03(\x08\x1a\x1a\n\nStringList\x12\x0c\n\x04vals\x18\x01 \x03(\t\x1a\x19\n\tBytesList\x12\x0c\n\x04vals\x18\x01 \x03(\x0c\x42\x07\n\x05value\"\xa0\x01\n\x11SecureAggregation\x12\x44\n\x0cnamed_values\x18\x01 \x03(\x0b\x32..flwr.proto.SecureAggregation.NamedValuesEntry\x1a\x45\n\x10NamedValuesEntry\x12\x0b\n\x03key\x18\x01 \x01(\t\x12 \n\x05value\x18\x02 \x01(\x0b\x32\x11.flwr.proto.Value:\x02\x38\x01\x62\x06proto3')
 
 
 
diff --git a/src/py/flwr/proto/task_pb2.pyi b/src/py/flwr/proto/task_pb2.pyi
index dcd4686944bc..7cf96cb61edf 100644
--- a/src/py/flwr/proto/task_pb2.pyi
+++ b/src/py/flwr/proto/task_pb2.pyi
@@ -63,14 +63,14 @@ class TaskIns(google.protobuf.message.Message):
     TASK_FIELD_NUMBER: builtins.int
     task_id: typing.Text
     group_id: typing.Text
-    workload_id: typing.Text
+    workload_id: builtins.int
     @property
     def task(self) -> global___Task: ...
     def __init__(self,
         *,
         task_id: typing.Text = ...,
         group_id: typing.Text = ...,
-        workload_id: typing.Text = ...,
+        workload_id: builtins.int = ...,
         task: typing.Optional[global___Task] = ...,
         ) -> None: ...
     def HasField(self, field_name: typing_extensions.Literal["task",b"task"]) -> builtins.bool: ...
@@ -85,14 +85,14 @@ class TaskRes(google.protobuf.message.Message):
     TASK_FIELD_NUMBER: builtins.int
     task_id: typing.Text
     group_id: typing.Text
-    workload_id: typing.Text
+    workload_id: builtins.int
     @property
     def task(self) -> global___Task: ...
     def __init__(self,
         *,
         task_id: typing.Text = ...,
         group_id: typing.Text = ...,
-        workload_id: typing.Text = ...,
+        workload_id: builtins.int = ...,
         task: typing.Optional[global___Task] = ...,
         ) -> None: ...
     def HasField(self, field_name: typing_extensions.Literal["task",b"task"]) -> builtins.bool: ...
diff --git a/src/py/flwr/server/fleet/message_handler/message_handler_test.py b/src/py/flwr/server/fleet/message_handler/message_handler_test.py
index 10f678e3479e..da92b267f082 100644
--- a/src/py/flwr/server/fleet/message_handler/message_handler_test.py
+++ b/src/py/flwr/server/fleet/message_handler/message_handler_test.py
@@ -109,7 +109,7 @@ def test_push_task_res() -> None:
             TaskRes(
                 task_id="",
                 group_id="",
-                workload_id="",
+                workload_id=0,
                 task=Task(),
             ),
         ],
diff --git a/src/py/flwr/server/state/in_memory_state.py b/src/py/flwr/server/state/in_memory_state.py
index 075ba2cf304d..d6292571cd6d 100644
--- a/src/py/flwr/server/state/in_memory_state.py
+++ b/src/py/flwr/server/state/in_memory_state.py
@@ -32,7 +32,7 @@ class InMemoryState(State):
 
     def __init__(self) -> None:
         self.node_ids: Set[int] = set()
-        self.workload_ids: Set[str] = set()
+        self.workload_ids: Set[int] = set()
         self.task_ins_store: Dict[UUID, TaskIns] = {}
         self.task_res_store: Dict[UUID, TaskRes] = {}
 
@@ -194,7 +194,7 @@ def unregister_node(self, node_id: int) -> None:
             raise ValueError(f"Node {node_id} is not registered")
         self.node_ids.remove(node_id)
 
-    def get_nodes(self, workload_id: str) -> Set[int]:
+    def get_nodes(self, workload_id: int) -> Set[int]:
         """Return all available client nodes.
 
         Constraints
@@ -206,14 +206,13 @@ def get_nodes(self, workload_id: str) -> Set[int]:
             return set()
         return self.node_ids
 
-    def create_workload(self) -> str:
+    def create_workload(self) -> int:
         """Create one workload."""
-        # String representation of random integer from 0 to 9223372036854775807
-        random_workload_id: int = random.randrange(9223372036854775808)
-        workload_id = str(random_workload_id)
+        # Sample random integer from 0 to 9223372036854775807
+        workload_id: int = random.randrange(9223372036854775808)
 
         if workload_id not in self.workload_ids:
             self.workload_ids.add(workload_id)
             return workload_id
         log(ERROR, "Unexpected workload creation failure.")
-        return ""
+        return 0
diff --git a/src/py/flwr/server/state/sqlite_state.py b/src/py/flwr/server/state/sqlite_state.py
index e971c11da2f5..0c853409b844 100644
--- a/src/py/flwr/server/state/sqlite_state.py
+++ b/src/py/flwr/server/state/sqlite_state.py
@@ -39,7 +39,7 @@
 
 SQL_CREATE_TABLE_WORKLOAD = """
 CREATE TABLE IF NOT EXISTS workload(
-    workload_id TEXT UNIQUE
+    workload_id INTEGER UNIQUE
 );
 """
 
@@ -47,7 +47,7 @@
 CREATE TABLE IF NOT EXISTS task_ins(
     task_id                 TEXT UNIQUE,
     group_id                TEXT,
-    workload_id             TEXT,
+    workload_id             INTEGER,
     producer_anonymous      BOOLEAN,
     producer_node_id        INTEGER,
     consumer_anonymous      BOOLEAN,
@@ -67,7 +67,7 @@
 CREATE TABLE IF NOT EXISTS task_res(
     task_id                 TEXT UNIQUE,
     group_id                TEXT,
-    workload_id             TEXT,
+    workload_id             INTEGER,
     producer_anonymous      BOOLEAN,
     producer_node_id        INTEGER,
     consumer_anonymous      BOOLEAN,
@@ -479,7 +479,7 @@ def unregister_node(self, node_id: int) -> None:
         query = "DELETE FROM node WHERE node_id = :node_id;"
         self.query(query, {"node_id": node_id})
 
-    def get_nodes(self, workload_id: str) -> Set[int]:
+    def get_nodes(self, workload_id: int) -> Set[int]:
         """Retrieve all currently stored node IDs as a set.
 
         Constraints
@@ -498,11 +498,10 @@ def get_nodes(self, workload_id: str) -> Set[int]:
         result: Set[int] = {row["node_id"] for row in rows}
         return result
 
-    def create_workload(self) -> str:
+    def create_workload(self) -> int:
         """Create one workload and store it in state."""
-        # String representation of random integer from 0 to 9223372036854775807
-        random_workload_id: int = random.randrange(9223372036854775808)
-        workload_id = str(random_workload_id)
+        # Sample random integer from 0 to 9223372036854775807
+        workload_id: int = random.randrange(9223372036854775808)
 
         # Check conflicts
         query = "SELECT COUNT(*) FROM workload WHERE workload_id = ?;"
@@ -512,7 +511,7 @@ def create_workload(self) -> str:
             self.query(query, {"workload_id": workload_id})
             return workload_id
         log(ERROR, "Unexpected workload creation failure.")
-        return ""
+        return 0
 
 
 def dict_factory(
diff --git a/src/py/flwr/server/state/sqlite_state_test.py b/src/py/flwr/server/state/sqlite_state_test.py
index e3bb72e34118..b9c0df9ed134 100644
--- a/src/py/flwr/server/state/sqlite_state_test.py
+++ b/src/py/flwr/server/state/sqlite_state_test.py
@@ -27,7 +27,7 @@ class SqliteStateTest(unittest.TestCase):
     def test_ins_res_to_dict(self) -> None:
         """Check if all required keys are included in return value."""
         # Prepare
-        ins_res = create_task_ins(consumer_node_id=1, anonymous=True, workload_id="")
+        ins_res = create_task_ins(consumer_node_id=1, anonymous=True, workload_id=0)
         expected_keys = [
             "task_id",
             "group_id",
diff --git a/src/py/flwr/server/state/state.py b/src/py/flwr/server/state/state.py
index cfd68c589b6e..a0b9e663f637 100644
--- a/src/py/flwr/server/state/state.py
+++ b/src/py/flwr/server/state/state.py
@@ -140,7 +140,7 @@ def unregister_node(self, node_id: int) -> None:
         """Remove `node_id` from state."""
 
     @abc.abstractmethod
-    def get_nodes(self, workload_id: str) -> Set[int]:
+    def get_nodes(self, workload_id: int) -> Set[int]:
         """Retrieve all currently stored node IDs as a set.
 
         Constraints
@@ -150,5 +150,5 @@ def get_nodes(self, workload_id: str) -> Set[int]:
         """
 
     @abc.abstractmethod
-    def create_workload(self) -> str:
+    def create_workload(self) -> int:
         """Create one workload."""
diff --git a/src/py/flwr/server/state/state_test.py b/src/py/flwr/server/state/state_test.py
index e80bd55352ed..bc3015ba5cc2 100644
--- a/src/py/flwr/server/state/state_test.py
+++ b/src/py/flwr/server/state/state_test.py
@@ -283,7 +283,7 @@ def test_task_ins_store_invalid_workload_id_and_fail(self) -> None:
         # Prepare
         state: State = self.state_factory()
         task_ins = create_task_ins(
-            consumer_node_id=0, anonymous=True, workload_id="I'm invalid"
+            consumer_node_id=0, anonymous=True, workload_id=61016
         )
 
         # Execute
@@ -362,7 +362,7 @@ def test_get_nodes_invalid_workload_id(self) -> None:
         # Prepare
         state: State = self.state_factory()
         state.create_workload()
-        invalid_workload_id = ""
+        invalid_workload_id = 61016
         node_id = 2
 
         # Execute
@@ -420,7 +420,7 @@ def test_num_task_res(self) -> None:
 def create_task_ins(
     consumer_node_id: int,
     anonymous: bool,
-    workload_id: str,
+    workload_id: int,
     delivered_at: str = "",
 ) -> TaskIns:
     """Create a TaskIns for testing."""
@@ -448,7 +448,7 @@ def create_task_res(
     producer_node_id: int,
     anonymous: bool,
     ancestry: List[str],
-    workload_id: str,
+    workload_id: int,
 ) -> TaskRes:
     """Create a TaskRes for testing."""
     task_res = TaskRes(
diff --git a/src/py/flwr/server/utils/validator_test.py b/src/py/flwr/server/utils/validator_test.py
index 533e3a236572..54840731048f 100644
--- a/src/py/flwr/server/utils/validator_test.py
+++ b/src/py/flwr/server/utils/validator_test.py
@@ -135,7 +135,7 @@ def create_task_ins(
     task = TaskIns(
         task_id="",
         group_id="",
-        workload_id="",
+        workload_id=0,
         task=Task(
             delivered_at=delivered_at,
             producer=Node(node_id=0, anonymous=True),
@@ -162,7 +162,7 @@ def create_task_res(
     task_res = TaskRes(
         task_id="",
         group_id="",
-        workload_id="",
+        workload_id=0,
         task=Task(
             producer=Node(node_id=producer_node_id, anonymous=anonymous),
             consumer=Node(node_id=0, anonymous=True),