diff --git a/examples/hello-world/python_jobs/client-api-pt/cifar10_fl.py b/examples/hello-world/python_jobs/client-api-pt/cifar10_fl.py
new file mode 100644
index 0000000000..5bd28adc14
--- /dev/null
+++ b/examples/hello-world/python_jobs/client-api-pt/cifar10_fl.py
@@ -0,0 +1,136 @@
+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import torch
+import torch.nn as nn
+import torch.optim as optim
+import torchvision
+import torchvision.transforms as transforms
+from net import Net
+
+# (1) import nvflare client API
+import nvflare.client as flare
+
+# (optional) metrics
+from nvflare.client.tracking import SummaryWriter
+
+# (optional) set a fix place so we don't need to download everytime
+DATASET_PATH = "/tmp/nvflare/data"
+# If available, we use GPU to speed things up.
+DEVICE = "cuda" if torch.cuda.is_available() else "cpu"
+
+
+def main():
+    transform = transforms.Compose([transforms.ToTensor(), transforms.Normalize((0.5, 0.5, 0.5), (0.5, 0.5, 0.5))])
+
+    batch_size = 4
+    epochs = 2
+
+    trainset = torchvision.datasets.CIFAR10(root=DATASET_PATH, train=True, download=True, transform=transform)
+    trainloader = torch.utils.data.DataLoader(trainset, batch_size=batch_size, shuffle=True, num_workers=2)
+
+    testset = torchvision.datasets.CIFAR10(root=DATASET_PATH, train=False, download=True, transform=transform)
+    testloader = torch.utils.data.DataLoader(testset, batch_size=batch_size, shuffle=False, num_workers=2)
+
+    net = Net()
+
+    # (2) initializes NVFlare client API
+    flare.init()
+
+    summary_writer = SummaryWriter()
+    while flare.is_running():
+        # (3) receives FLModel from NVFlare
+        input_model = flare.receive()
+        print(f"current_round={input_model.current_round}")
+
+        # (4) loads model from NVFlare
+        net.load_state_dict(input_model.params)
+
+        criterion = nn.CrossEntropyLoss()
+        optimizer = optim.SGD(net.parameters(), lr=0.001, momentum=0.9)
+
+        # (optional) use GPU to speed things up
+        net.to(DEVICE)
+        # (optional) calculate total steps
+        steps = epochs * len(trainloader)
+        for epoch in range(epochs):  # loop over the dataset multiple times
+
+            running_loss = 0.0
+            for i, data in enumerate(trainloader, 0):
+                # get the inputs; data is a list of [inputs, labels]
+                # (optional) use GPU to speed things up
+                inputs, labels = data[0].to(DEVICE), data[1].to(DEVICE)
+
+                # zero the parameter gradients
+                optimizer.zero_grad()
+
+                # forward + backward + optimize
+                outputs = net(inputs)
+                loss = criterion(outputs, labels)
+                loss.backward()
+                optimizer.step()
+
+                # print statistics
+                running_loss += loss.item()
+                if i % 2000 == 1999:  # print every 2000 mini-batches
+                    print(f"[{epoch + 1}, {i + 1:5d}] loss: {running_loss / 2000:.3f}")
+                    global_step = input_model.current_round * steps + epoch * len(trainloader) + i
+
+                    summary_writer.add_scalar(tag="loss_for_each_batch", scalar=running_loss, global_step=global_step)
+                    running_loss = 0.0
+
+        print("Finished Training")
+
+        PATH = "./cifar_net.pth"
+        torch.save(net.state_dict(), PATH)
+
+        # (5) wraps evaluation logic into a method to re-use for
+        #       evaluation on both trained and received model
+        def evaluate(input_weights):
+            net = Net()
+            net.load_state_dict(input_weights)
+            # (optional) use GPU to speed things up
+            net.to(DEVICE)
+
+            correct = 0
+            total = 0
+            # since we're not training, we don't need to calculate the gradients for our outputs
+            with torch.no_grad():
+                for data in testloader:
+                    # (optional) use GPU to speed things up
+                    images, labels = data[0].to(DEVICE), data[1].to(DEVICE)
+                    # calculate outputs by running images through the network
+                    outputs = net(images)
+                    # the class with the highest energy is what we choose as prediction
+                    _, predicted = torch.max(outputs.data, 1)
+                    total += labels.size(0)
+                    correct += (predicted == labels).sum().item()
+
+            print(f"Accuracy of the network on the 10000 test images: {100 * correct // total} %")
+            return 100 * correct // total
+
+        # (6) evaluate on received model for model selection
+        accuracy = evaluate(input_model.params)
+        # (7) construct trained FL model
+        output_model = flare.FLModel(
+            params=net.cpu().state_dict(),
+            metrics={"accuracy": accuracy},
+            meta={"NUM_STEPS_CURRENT_ROUND": steps},
+        )
+        # (8) send model back to NVFlare
+        flare.send(output_model)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/examples/hello-world/python_jobs/client-api-pt/client_api_pt_job.py b/examples/hello-world/python_jobs/client-api-pt/client_api_pt_job.py
new file mode 100644
index 0000000000..5bfa284a13
--- /dev/null
+++ b/examples/hello-world/python_jobs/client-api-pt/client_api_pt_job.py
@@ -0,0 +1,181 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import uuid
+from typing import Union, List
+
+from nvflare.job_config.fed_app_config import ClientAppConfig, ServerAppConfig, FedAppConfig
+from nvflare.job_config.fed_job_config import FedJobConfig
+from nvflare.app_common.widgets.validation_json_generator import ValidationJsonGenerator
+from nvflare.app_common.workflows.cross_site_model_eval import CrossSiteModelEval
+from nvflare.app_opt.pt import PTFileModelPersistor
+from nvflare.app_opt.pt.client_api_launcher_executor import PTClientAPILauncherExecutor
+from nvflare.app_common.launchers.subprocess_launcher import SubprocessLauncher
+from nvflare.app_common.widgets.metric_relay import MetricRelay
+from nvflare.app_common.widgets.external_configurator import ExternalConfigurator
+from nvflare.app_common.workflows.fedavg import FedAvg
+from nvflare.app_opt.pt.file_model_locator import PTFileModelLocator
+from nvflare.fuel.utils.constants import Mode
+from nvflare.fuel.utils.pipe.file_pipe import FilePipe
+from net import Net
+from nvflare.app_common.widgets.intime_model_selector import IntimeModelSelector
+from nvflare.app_opt.tracking.tb.tb_receiver import TBAnalyticsReceiver
+from nvflare.app_opt.pt.in_process_client_api_executor import PTInProcessClientAPIExecutor
+
+
+class FedApp:
+    def __init__(self):
+        self.app = None  # Union[ClientAppConfig, ServerAppConfig]
+
+    def get_app_config(self):
+        return self.app
+
+
+class FedJob:
+    def __init__(self, name="client-api-pt", workspace="/tmp/nvflare/simulator_workspace") -> None:
+        self.job_name = name
+        self.workspace = workspace
+
+        self.job: FedJobConfig = FedJobConfig(job_name=self.job_name, min_clients=1)
+
+    def to(self, app: FedApp, target):
+        if not isinstance(app, FedApp):
+            raise ValueError(f"App needs to be of type `FedApp` but was type {type(app)}")
+
+        client_server_config = app.get_app_config()
+        if isinstance(client_server_config, ClientAppConfig):
+            app_config = FedAppConfig(server_app=None, client_app=client_server_config)
+            app_name = f"app_client_{(uuid.uuid4())}"
+        elif isinstance(client_server_config, ServerAppConfig):
+            app_config = FedAppConfig(server_app=client_server_config, client_app=None)
+            app_name = f"app_server_{(uuid.uuid4())}"
+        else:
+            raise ValueError(f"App needs to be of type `ClientAppConfig` or `ServerAppConfig` but was type {type(client_server_config)}")
+
+        self.job.add_fed_app(app_name, app_config)
+        self.job.set_site_app(target, app_name)
+
+    def export_job(self, job_root):
+        self.job.generate_job_config(job_root)
+
+    def simulator_run(self, job_root):
+        self.job.simulator_run(job_root, self.workspace, threads=2)
+
+
+class ExecutorApp(FedApp):
+    def __init__(self, executors: List):
+        super().__init__()
+        self.executors = executors
+        #self._site_name = f"site_{uuid.uuid4()}"
+        #self._job_id = f"{uuid.uuid4()}"
+        self._create_client_app()
+
+    def _create_client_app(self):
+        self.app = ClientAppConfig()
+
+        for _executor in self.executors:
+            self.app.add_executor(["train"], _executor)
+
+        component = FilePipe(
+            mode="PASSIVE",  #TODO: enable passing Mode.PASSIVE
+            root_path="{WORKSPACE}/{JOB_ID}/{SITE_NAME}"  # TODO: this creates empty subfolder structure
+        )
+        self.app.add_component("metrics_pipe", component)
+
+        component = MetricRelay(
+            pipe_id="metrics_pipe",
+            event_type="fed.analytix_log_stats",
+            read_interval=0.1
+        )
+        self.app.add_component("metric_relay", component)
+
+        component = ExternalConfigurator(
+            component_ids=["metric_relay"]
+        )
+        self.app.add_component("config_preparer", component)
+
+        #self.app.add_component("net", Net())  # TODO: find another way to register files that need to be included in custom folder
+        self.app.add_ext_script("cifar10_fl.py")
+
+
+class ControllerApp(FedApp):
+    def __init__(self, controllers: List, model_class_path=Net()):
+        super().__init__()
+        self.controllers = controllers
+        self.model_class_path = model_class_path
+        self._create_server_app()
+        
+    def _create_server_app(self):
+        self.app: ServerAppConfig = ServerAppConfig()
+
+        for i, _controller in enumerate(self.controllers):
+            self.app.add_workflow(f"controller_{i}", _controller)
+
+        # TODO: make optional or list of controllers? # add as new example
+        #_controller = CrossSiteModelEval(model_locator_id="model_locator")
+        #self.app.add_workflow("cross_site_validate", _controller)
+    
+        component = PTFileModelPersistor(
+            model=Net()
+        )
+    
+        self.app.add_component("persistor", component)
+    
+        component = PTFileModelLocator(
+            pt_persistor_id="persistor"
+        )
+        self.app.add_component("model_locator", component)
+    
+        component = ValidationJsonGenerator()
+        self.app.add_component("json_generator", component)
+    
+        component = IntimeModelSelector(
+            key_metric="accuracy"
+        )
+        self.app.add_component("model_selector", component)
+    
+        component = TBAnalyticsReceiver(
+            events=["fed.analytix_log_stats"]
+        )
+        self.app.add_component("receiver", component)
+    
+        #self.app.add_component("net", Net())  # TODO: have another way to register needed scripts
+
+
+if __name__ == "__main__":
+    n_clients = 2
+    num_rounds = 2
+
+    job = FedJob(name="cifar10_fedavg")
+
+    controller = FedAvg(
+        min_clients=n_clients,
+        num_rounds=num_rounds,
+        persistor_id="persistor"  # TODO: why is it not using default
+    )
+    server_app = ControllerApp(controllers=[controller])
+    job.to(server_app, "server")
+
+    for i in range(n_clients):
+        executor = PTInProcessClientAPIExecutor(
+            task_fn_path="cifar10_fl.main",
+            #task_fn_args={"batch_size": 1}
+        )
+        client_app = ExecutorApp(executors=[executor])
+        job.to(client_app, f"site-{i}")
+
+    job.export_job("/tmp/nvflare/jobs/job_config")
+    job.simulator_run("/tmp/nvflare/jobs/workdir")
+
+
diff --git a/examples/hello-world/python_jobs/client-api-pt/net.py b/examples/hello-world/python_jobs/client-api-pt/net.py
new file mode 100644
index 0000000000..1e86a406f0
--- /dev/null
+++ b/examples/hello-world/python_jobs/client-api-pt/net.py
@@ -0,0 +1,38 @@
+# Copyright (c) 2023, NVIDIA CORPORATION.  All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+
+class Net(nn.Module):
+    def __init__(self):
+        super().__init__()
+        self.conv1 = nn.Conv2d(3, 6, 5)
+        self.pool = nn.MaxPool2d(2, 2)
+        self.conv2 = nn.Conv2d(6, 16, 5)
+        self.fc1 = nn.Linear(16 * 5 * 5, 120)
+        self.fc2 = nn.Linear(120, 84)
+        self.fc3 = nn.Linear(84, 10)
+
+    def forward(self, x):
+        #from cifar10_fl import main   # TODO: remove
+        x = self.pool(F.relu(self.conv1(x)))
+        x = self.pool(F.relu(self.conv2(x)))
+        x = torch.flatten(x, 1)  # flatten all dimensions except batch
+        x = F.relu(self.fc1(x))
+        x = F.relu(self.fc2(x))
+        x = self.fc3(x)
+        return x
diff --git a/nvflare/app_opt/pt/in_process_client_api_executor.py b/nvflare/app_opt/pt/in_process_client_api_executor.py
index 3998567985..165fcee77e 100644
--- a/nvflare/app_opt/pt/in_process_client_api_executor.py
+++ b/nvflare/app_opt/pt/in_process_client_api_executor.py
@@ -25,7 +25,7 @@ class PTInProcessClientAPIExecutor(InProcessClientAPIExecutor):
     def __init__(
         self,
         task_fn_path: str,
-        task_fn_args: Dict = {},
+        task_fn_args: Dict = None,
         task_wait_time: Optional[float] = None,
         result_pull_interval: float = 0.5,
         log_pull_interval: Optional[float] = None,