diff --git a/manifests/nginx_ingress_http.yaml b/manifests/nginx_ingress_http.yaml
index 955d5726a9f8f79560327a8f595c1865f6d37d22..c0a0875e2b0afdc0f18e1578370dbbcce5b88cde 100644
--- a/manifests/nginx_ingress_http.yaml
+++ b/manifests/nginx_ingress_http.yaml
@@ -62,3 +62,10 @@ spec:
                 name: nbiservice
                 port:
                   number: 8080
+                    - path: /()(qkd_app/.*)
+          - pathType: Prefix
+            backend:
+              service:
+                name: qkdappservice
+                port:
+                  number: 8005
diff --git a/manifests/qkdappservice.yaml b/manifests/qkdappservice.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..13f16f4e501b20208b93e3edcff9c161744632d2
--- /dev/null
+++ b/manifests/qkdappservice.yaml
@@ -0,0 +1,85 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
+
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: qkdappservice
+spec:
+  selector:
+    matchLabels:
+      app: qkdappservice
+  #replicas: 1
+  template:
+    metadata:
+      labels:
+        app: qkdappservice
+    spec:
+      terminationGracePeriodSeconds: 5
+      containers:
+      - name: server
+        image: labs.etsi.org:5050/tfs/controller/qkd_app:latest
+        imagePullPolicy: Always
+        ports:
+        - containerPort: 10060
+        - containerPort: 9192
+        - containerPort: 8005
+        env:
+        - name: MB_BACKEND
+          value: "nats"
+        - name: LOG_LEVEL
+          value: "INFO"
+        - name: CRDB_DATABASE_APP
+          value: "qkd_app"
+        envFrom:
+        - secretRef:
+            name: crdb-data
+        - secretRef:
+            name: nats-data
+        readinessProbe:
+          exec:
+            command: ["/bin/grpc_health_probe", "-addr=:10060"]
+        livenessProbe:
+          exec:
+            command: ["/bin/grpc_health_probe", "-addr=:10060"]
+        resources:
+          requests:
+            cpu: 150m
+            memory: 128Mi
+          limits:
+            cpu: 500m
+            memory: 512Mi
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: qkdappservice
+  labels:
+    app: qkdappservice
+spec:
+  type: ClusterIP
+  selector:
+    app: qkdappservice
+  ports:
+  - name: grpc
+    protocol: TCP
+    port: 10060
+    targetPort: 10060
+  - name: metrics
+    protocol: TCP
+    port: 9192
+    targetPort: 9192
+  - name: http
+    port: 8005
+    targetPort: 8005
diff --git a/my_deploy.sh b/my_deploy.sh
index 88be82b63e9e79a97ee79702de886f69a6152f94..ee17cb3679f6390115917a005cfaf670585c28c7 100755
--- a/my_deploy.sh
+++ b/my_deploy.sh
@@ -71,7 +71,14 @@ export TFS_COMPONENTS="context device pathcomp service slice nbi webui load_gene
 #fi
 
 # Uncomment to activate QKD App
-#export TFS_COMPONENTS="${TFS_COMPONENTS} app"
+#   To manage QKD Apps, "service" requires "qkd_app" to be deployed
+#   before "service", thus we "hack" the TFS_COMPONENTS environment variable prepending the
+#   "qkd_app" only if "service" is already in TFS_COMPONENTS, and re-export it.
+#if [[ "$TFS_COMPONENTS" == *"service"* ]]; then
+#    BEFORE="${TFS_COMPONENTS% service*}"
+#    AFTER="${TFS_COMPONENTS#* service}"
+#    export TFS_COMPONENTS="${BEFORE} qkd_app service ${AFTER}"
+#fi
 
 
 # Set the tag you want to use for your images.
diff --git a/proto/qkd_app.proto b/proto/qkd_app.proto
new file mode 100644
index 0000000000000000000000000000000000000000..7b6c47330833849b889e770aac43844ec6e6072c
--- /dev/null
+++ b/proto/qkd_app.proto
@@ -0,0 +1,53 @@
+syntax = "proto3";
+package qkd_app;
+
+import "context.proto";
+
+// Optare: Change this if you want to change App's structure or enums. 
+// Optare: If a message (structure) is changed it must be changed in src/app/service/database
+
+enum QKDAppStatusEnum {
+  QKDAPPSTATUS_ON = 0;
+  QKDAPPSTATUS_DISCONNECTED = 1;
+  QKDAPPSTATUS_OUT_OF_TIME = 2;
+  QKDAPPSTATUS_ZOMBIE = 3;
+}
+
+enum QKDAppTypesEnum {
+  QKDAPPTYPES_INTERNAL = 0;
+  QKDAPPTYPES_CLIENT = 1;
+}
+
+message QKDLId {
+  context.Uuid qkdl_uuid = 1;
+}
+
+
+message App {
+  AppId app_id = 1;
+  QKDAppStatusEnum app_status = 2;
+  QKDAppTypesEnum app_type = 3;
+  string server_app_id = 4;
+  repeated string client_app_id = 5;
+  repeated QKDLId backing_qkdl_id = 6;
+  context.DeviceId local_device_id = 7;
+  context.DeviceId remote_device_id = 8;
+}
+
+
+message AppId {
+  context.ContextId context_id = 1;
+  context.Uuid app_uuid = 2;
+}
+
+
+service AppService {
+  rpc RegisterApp(App) returns (context.Empty) {}
+  rpc ListApps       (context.ContextId     ) returns (       AppList     ) {}
+ }
+ 
+
+
+ message AppList {
+  repeated App apps = 1;
+}
diff --git a/src/common/Constants.py b/src/common/Constants.py
index 74490321f9c8ec016fa4b48b583e2217c61710ec..8b2e215a0ee669726430d12ea4ebac334f69c1ce 100644
--- a/src/common/Constants.py
+++ b/src/common/Constants.py
@@ -61,6 +61,7 @@ class ServiceNameEnum(Enum):
     E2EORCHESTRATOR        = 'e2e-orchestrator'
     OPTICALCONTROLLER      = 'opticalcontroller'
     BGPLS                  = 'bgpls-speaker'
+    QKD_APP                = 'qkd_app'
     KPIMANAGER             = 'kpi-manager'
     KPIVALUEAPI            = 'kpi-value-api'
     KPIVALUEWRITER         = 'kpi-value-writer'
@@ -96,6 +97,7 @@ DEFAULT_SERVICE_GRPC_PORTS = {
     ServiceNameEnum.FORECASTER             .value : 10040,
     ServiceNameEnum.E2EORCHESTRATOR        .value : 10050,
     ServiceNameEnum.OPTICALCONTROLLER      .value : 10060,
+    ServiceNameEnum.QKD_APP                .value : 10070,
     ServiceNameEnum.BGPLS                  .value : 20030,
     ServiceNameEnum.KPIMANAGER             .value : 30010,
     ServiceNameEnum.KPIVALUEAPI            .value : 30020,
@@ -115,10 +117,12 @@ DEFAULT_SERVICE_HTTP_PORTS = {
     ServiceNameEnum.CONTEXT   .value : 8080,
     ServiceNameEnum.NBI       .value : 8080,
     ServiceNameEnum.WEBUI     .value : 8004,
+    ServiceNameEnum.QKD_APP   .value : 8005,
 }
 
 # Default HTTP/REST-API service base URLs
 DEFAULT_SERVICE_HTTP_BASEURLS = {
     ServiceNameEnum.NBI       .value : None,
     ServiceNameEnum.WEBUI     .value : None,
+    ServiceNameEnum.QKD_APP   .value : None,
 }
diff --git a/src/common/tools/object_factory/QKDApp.py b/src/common/tools/object_factory/QKDApp.py
new file mode 100644
index 0000000000000000000000000000000000000000..936a0f228302469ec51321623f8d8050f3daced0
--- /dev/null
+++ b/src/common/tools/object_factory/QKDApp.py
@@ -0,0 +1,24 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 copy
+from typing import Dict, List, Optional
+from common.Constants import DEFAULT_CONTEXT_NAME
+from common.tools.object_factory.Context import json_context_id
+
+
+def json_app_id(app_uuid : str, context_id : Optional[Dict] = None) -> Dict:
+    result = {'app_uuid': {'uuid': app_uuid}}
+    if context_id is not None: result['context_id'] = copy.deepcopy(context_id)
+    return result
diff --git a/src/qkd_app/__init__.py b/src/qkd_app/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/__main__.py b/src/qkd_app/__main__.py
new file mode 100644
index 0000000000000000000000000000000000000000..ed7e554728eb2de6240dd4facb7f084337a026a4
--- /dev/null
+++ b/src/qkd_app/__main__.py
@@ -0,0 +1,94 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 logging, signal, sys, threading
+from prometheus_client import start_http_server
+#from common.Constants import ServiceNameEnum
+from common.Settings import (
+    #ENVVAR_SUFIX_SERVICE_HOST, ENVVAR_SUFIX_SERVICE_PORT_GRPC, get_env_var_name,
+    get_log_level, get_metrics_port, wait_for_environment_variables)
+from qkd_app.service.QKDAppService import AppService
+from qkd_app.service.rest_server.RestServer import RestServer
+from qkd_app.service.rest_server.qkd_app import register_qkd_app
+#from common.message_broker.Factory import get_messagebroker_backend
+#from common.message_broker.MessageBroker import MessageBroker
+from qkd_app.service.database.Engine import Engine
+from qkd_app.service.database.models._Base import rebuild_database
+
+terminate = threading.Event()
+LOGGER : logging.Logger = None
+
+def signal_handler(signal, frame): # pylint: disable=redefined-outer-name
+    LOGGER.warning('Terminate signal received')
+    terminate.set()
+
+def main():
+    global LOGGER # pylint: disable=global-statement
+
+    log_level = get_log_level()
+    logging.basicConfig(level=log_level, format="[%(asctime)s] %(levelname)s:%(name)s:%(message)s")
+    LOGGER = logging.getLogger(__name__)
+
+    wait_for_environment_variables([
+        #get_env_var_name(ServiceNameEnum.CONTEXT, ENVVAR_SUFIX_SERVICE_HOST     ),
+        #get_env_var_name(ServiceNameEnum.CONTEXT, ENVVAR_SUFIX_SERVICE_PORT_GRPC),
+    ])
+
+    signal.signal(signal.SIGINT,  signal_handler)
+    signal.signal(signal.SIGTERM, signal_handler)
+
+    LOGGER.info('Starting...')
+
+    # Start metrics server
+    metrics_port = get_metrics_port()
+    start_http_server(metrics_port)
+
+    # Get Database Engine instance and initialize database, if needed
+    LOGGER.info('Getting SQLAlchemy DB Engine...')
+    db_engine = Engine.get_engine()
+    if db_engine is None:
+        LOGGER.error('Unable to get SQLAlchemy DB Engine...')
+        return -1
+
+    try:
+        Engine.create_database(db_engine)
+    except: # pylint: disable=bare-except # pragma: no cover
+        LOGGER.exception('Failed to check/create the database: {:s}'.format(str(db_engine.url)))
+
+    rebuild_database(db_engine)
+
+    # Get message broker instance
+    messagebroker = None #MessageBroker(get_messagebroker_backend())
+
+    # Starting context service
+    grpc_service = AppService(db_engine, messagebroker)
+    grpc_service.start()
+
+    rest_server = RestServer()
+    register_qkd_app(rest_server)
+    rest_server.start()
+
+    # Wait for Ctrl+C or termination signal
+    while not terminate.wait(timeout=1.0): pass
+
+    LOGGER.info('Terminating...')
+    grpc_service.stop()
+    rest_server.shutdown()
+    rest_server.join()
+
+    LOGGER.info('Bye')
+    return 0
+
+if __name__ == '__main__':
+    sys.exit(main())
diff --git a/src/qkd_app/client/QKDAppClient.py b/src/qkd_app/client/QKDAppClient.py
new file mode 100644
index 0000000000000000000000000000000000000000..b8c09329f9511868a1013ea41a0d8890da499218
--- /dev/null
+++ b/src/qkd_app/client/QKDAppClient.py
@@ -0,0 +1,64 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 grpc, logging
+from common.Constants import ServiceNameEnum
+from common.Settings import get_service_host, get_service_port_grpc
+from common.proto.context_pb2 import Empty, ContextId
+from common.proto.qkd_app_pb2 import App, AppId, AppList
+from common.proto.qkd_app_pb2_grpc import AppServiceStub
+from common.tools.client.RetryDecorator import retry, delay_exponential
+from common.tools.grpc.Tools import grpc_message_to_json_string
+
+LOGGER = logging.getLogger(__name__)
+MAX_RETRIES = 15
+DELAY_FUNCTION = delay_exponential(initial=0.01, increment=2.0, maximum=5.0)
+RETRY_DECORATOR = retry(max_retries=MAX_RETRIES, delay_function=DELAY_FUNCTION, prepare_method_name='connect')
+
+class QKDAppClient:
+    def __init__(self, host=None, port=None):
+        if not host: host = get_service_host(ServiceNameEnum.APP)
+        if not port: port = get_service_port_grpc(ServiceNameEnum.APP)
+        self.endpoint = '{:s}:{:s}'.format(str(host), str(port))
+        LOGGER.debug('Creating channel to {:s}...'.format(self.endpoint))
+        self.channel = None
+        self.stub = None
+        self.connect()
+        LOGGER.debug('Channel created')
+
+    def connect(self):
+        self.channel = grpc.insecure_channel(self.endpoint)
+        self.stub = AppServiceStub(self.channel)
+
+    def close(self):
+        if self.channel is not None: self.channel.close()
+        self.channel = None
+        self.stub = None
+
+
+
+    @RETRY_DECORATOR
+    def RegisterApp(self, request : App) -> Empty:
+        LOGGER.debug('RegisterApp request: {:s}'.format(grpc_message_to_json_string(request)))
+        response = self.stub.RegisterApp(request)
+        LOGGER.debug('RegisterApp result: {:s}'.format(grpc_message_to_json_string(response)))
+        return response
+
+    
+    @RETRY_DECORATOR
+    def ListApps(self, request: ContextId) -> AppList:
+        LOGGER.debug('ListApps request: {:s}'.format(grpc_message_to_json_string(request)))
+        response = self.stub.ListApps(request)
+        LOGGER.debug('ListApps result: {:s}'.format(grpc_message_to_json_string(response)))
+        return response
diff --git a/src/qkd_app/client/__init__.py b/src/qkd_app/client/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/client/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/service/QKDAppService.py b/src/qkd_app/service/QKDAppService.py
new file mode 100644
index 0000000000000000000000000000000000000000..fcf63efba3b390e0cb58e82430b2a2ce9feeef8d
--- /dev/null
+++ b/src/qkd_app/service/QKDAppService.py
@@ -0,0 +1,37 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 logging, sqlalchemy
+from common.Constants import ServiceNameEnum
+from common.Settings import get_service_port_grpc
+from common.message_broker.MessageBroker import MessageBroker
+from common.proto.qkd_app_pb2_grpc import add_AppServiceServicer_to_server
+from common.tools.service.GenericGrpcService import GenericGrpcService
+from qkd_app.service.QKDAppServiceServicerImpl import AppServiceServicerImpl
+
+# Custom gRPC settings
+GRPC_MAX_WORKERS = 200 # multiple clients might keep connections alive for Get*Events() RPC methods
+LOGGER = logging.getLogger(__name__)
+
+
+class AppService(GenericGrpcService):
+    def __init__(
+        self, db_engine : sqlalchemy.engine.Engine, messagebroker : MessageBroker, cls_name: str = __name__
+    ) -> None:
+        port = get_service_port_grpc(ServiceNameEnum.APP)
+        super().__init__(port, max_workers=GRPC_MAX_WORKERS, cls_name=cls_name)
+        self.app_servicer = AppServiceServicerImpl(db_engine, messagebroker)
+
+    def install_servicers(self):
+        add_AppServiceServicer_to_server(self.app_servicer, self.server)
diff --git a/src/qkd_app/service/QKDAppServiceServicerImpl.py b/src/qkd_app/service/QKDAppServiceServicerImpl.py
new file mode 100644
index 0000000000000000000000000000000000000000..df7a885c47eda9d7a6137c9905388da49c698e7e
--- /dev/null
+++ b/src/qkd_app/service/QKDAppServiceServicerImpl.py
@@ -0,0 +1,73 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 grpc, logging, sqlalchemy
+#from typing import Iterator, Optional
+from common.message_broker.MessageBroker import MessageBroker
+import grpc, json, logging #, deepdiff
+from common.proto.context_pb2 import (
+    Empty, Service, ServiceId, ServiceStatusEnum, ServiceTypeEnum, ContextId)
+from common.proto.qkd_app_pb2 import (App, AppId, AppList, QKDAppTypesEnum)
+from common.proto.qkd_app_pb2_grpc import AppServiceServicer
+from common.method_wrappers.Decorator import MetricsPool, safe_and_metered_rpc_method
+#from common.tools.context_queries.InterDomain import is_inter_domain #, is_multi_domain
+#from common.tools.grpc.ConfigRules import copy_config_rules
+#from common.tools.grpc.Constraints import copy_constraints
+#from common.tools.grpc.EndPointIds import copy_endpoint_ids
+#from common.tools.grpc.ServiceIds import update_service_ids
+#from common.tools.grpc.Tools import grpc_message_to_json_string
+#from context.client.ContextClient import ContextClient
+#from qkd_app.client.QKDAppClient import QKDAppClient
+from .database.QKDApp import app_set, app_list_objs, app_get, app_get_by_server
+from common.method_wrappers.ServiceExceptions import NotFoundException
+
+LOGGER = logging.getLogger(__name__)
+
+METRICS_POOL = MetricsPool('QkdApp', 'RPC')
+
+# Optare: This file must be edited based on app's logic
+
+class AppServiceServicerImpl(AppServiceServicer):
+    def __init__(self, db_engine : sqlalchemy.engine.Engine, messagebroker : MessageBroker):
+        LOGGER.debug('Creating Servicer...')
+        self.db_engine = db_engine
+        self.messagebroker = messagebroker
+        LOGGER.debug('Servicer Created')
+
+    @safe_and_metered_rpc_method(METRICS_POOL, LOGGER)
+    def RegisterApp(self, request : App, context : grpc.ServicerContext) -> Empty:
+        # Optare: This is the main function required for the project.
+        # Optare: If it's an internal it will save it directly. If it's an external one it will save it as pending by not providing the remote until the other party requests it too
+        # Optare: Ideally, the only thing needed to change is the code inside the try block. Currently it just searches by a pending app with the same server_id but you can put more restrictions or different search and raise the NotFoundException
+
+        if request.app_type == QKDAppTypesEnum.QKDAPPTYPES_INTERNAL:
+            app_set(self.db_engine, self.messagebroker, request)
+
+        else:
+            try:
+                app = app_get_by_server(self.db_engine, request.server_app_id)
+            except NotFoundException:
+                app = request
+                app_set(self.db_engine, self.messagebroker, app)
+            else:
+                app.remote_device_id.device_uuid.uuid = request.local_device_id.device_uuid.uuid
+                app_set(self.db_engine, self.messagebroker, app)
+                
+        
+        return Empty()
+    
+
+    @safe_and_metered_rpc_method(METRICS_POOL, LOGGER)
+    def ListApps(self, request: ContextId, context : grpc.ServicerContext) -> AppList:
+        return app_list_objs(self.db_engine)
diff --git a/src/qkd_app/service/database/Engine.py b/src/qkd_app/service/database/Engine.py
new file mode 100644
index 0000000000000000000000000000000000000000..8f528f9a1b3cacca2ea260901ab808461dd3183d
--- /dev/null
+++ b/src/qkd_app/service/database/Engine.py
@@ -0,0 +1,55 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 logging, sqlalchemy, sqlalchemy_utils
+from common.Settings import get_setting
+
+LOGGER = logging.getLogger(__name__)
+
+APP_NAME = 'tfs'
+ECHO = False # true: dump SQL commands and transactions executed
+CRDB_URI_TEMPLATE = 'cockroachdb://{:s}:{:s}@cockroachdb-public.{:s}.svc.cluster.local:{:s}/{:s}?sslmode={:s}'
+
+class Engine:
+    @staticmethod
+    def get_engine() -> sqlalchemy.engine.Engine:
+        crdb_uri = get_setting('CRDB_URI', default=None)
+        if crdb_uri is None:
+            CRDB_NAMESPACE = get_setting('CRDB_NAMESPACE')
+            CRDB_SQL_PORT  = get_setting('CRDB_SQL_PORT')
+            CRDB_DATABASE  = get_setting('CRDB_DATABASE_APP')
+            CRDB_USERNAME  = get_setting('CRDB_USERNAME')
+            CRDB_PASSWORD  = get_setting('CRDB_PASSWORD')
+            CRDB_SSLMODE   = get_setting('CRDB_SSLMODE')
+            crdb_uri = CRDB_URI_TEMPLATE.format(
+                CRDB_USERNAME, CRDB_PASSWORD, CRDB_NAMESPACE, CRDB_SQL_PORT, CRDB_DATABASE, CRDB_SSLMODE)
+
+        try:
+            engine = sqlalchemy.create_engine(
+                crdb_uri, connect_args={'application_name': APP_NAME}, echo=ECHO, future=True)
+        except: # pylint: disable=bare-except # pragma: no cover
+            LOGGER.exception('Failed to connect to database: {:s}'.format(str(crdb_uri)))
+            return None
+
+        return engine
+
+    @staticmethod
+    def create_database(engine : sqlalchemy.engine.Engine) -> None:
+        if not sqlalchemy_utils.database_exists(engine.url):
+            sqlalchemy_utils.create_database(engine.url)
+
+    @staticmethod
+    def drop_database(engine : sqlalchemy.engine.Engine) -> None:
+        if sqlalchemy_utils.database_exists(engine.url):
+            sqlalchemy_utils.drop_database(engine.url)
diff --git a/src/qkd_app/service/database/QKDApp.py b/src/qkd_app/service/database/QKDApp.py
new file mode 100644
index 0000000000000000000000000000000000000000..b1fb90d4efcd0770bcc4c48c1f00deb0e95687ad
--- /dev/null
+++ b/src/qkd_app/service/database/QKDApp.py
@@ -0,0 +1,185 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 datetime, logging, uuid
+from sqlalchemy.dialects.postgresql import insert
+from sqlalchemy.engine import Engine
+from sqlalchemy.orm import Session, selectinload, sessionmaker
+from sqlalchemy_cockroachdb import run_transaction
+from typing import Dict, List, Optional, Set, Tuple
+from common.method_wrappers.ServiceExceptions import InvalidArgumentException, NotFoundException
+from common.message_broker.MessageBroker import MessageBroker
+from common.proto.context_pb2 import Empty
+from common.proto.qkd_app_pb2 import (
+    AppList, App, AppId)
+from common.tools.grpc.Tools import grpc_message_to_json_string
+from .models.QKDAppModel import AppModel
+from .models.enums.QKDAppStatus import grpc_to_enum__qkd_app_status
+from .models.enums.QKDAppTypes import grpc_to_enum__qkd_app_types
+from .uuids.QKDApp import app_get_uuid
+from common.tools.object_factory.Context import json_context_id
+from common.tools.object_factory.QKDApp import json_app_id
+from context.service.database.uuids.Context import context_get_uuid
+
+
+
+#from .Events import notify_event_context, notify_event_device, notify_event_topology
+
+LOGGER = logging.getLogger(__name__)
+
+
+def app_list_objs(db_engine : Engine) -> AppList:
+    def callback(session : Session) -> List[Dict]:
+        obj_list : List[AppModel] = session.query(AppModel)\
+            .all()
+        return [obj.dump() for obj in obj_list]
+    apps = run_transaction(sessionmaker(bind=db_engine), callback)
+    return AppList(apps=apps)
+
+def app_get(db_engine : Engine, request : AppId) -> App:
+    app_uuid = app_get_uuid(request, allow_random=False)
+    def callback(session : Session) -> Optional[Dict]:
+        obj : Optional[AppModel] = session.query(AppModel)\
+            .filter_by(app_uuid=app_uuid).one_or_none()
+        return None if obj is None else obj.dump()
+    obj = run_transaction(sessionmaker(bind=db_engine), callback)
+    if obj is None:
+        raw_app_uuid = request.app_uuid.uuid
+        raise NotFoundException('App', raw_app_uuid, extra_details=[
+            'app_uuid generated was: {:s}'.format(app_uuid)
+        ])
+    return App(**obj)
+
+def app_set(db_engine : Engine, messagebroker : MessageBroker, request : App) -> AppId:
+    context_uuid = context_get_uuid(request.app_id.context_id, allow_random=False)
+    raw_app_uuid = request.app_id.app_uuid.uuid
+    app_uuid = app_get_uuid(request.app_id, allow_random=True)
+
+    app_type = request.app_type
+    app_status = grpc_to_enum__qkd_app_status(request.app_status)
+    app_type = grpc_to_enum__qkd_app_types(request.app_type)
+
+    now = datetime.datetime.utcnow()
+
+    
+    app_data = [{
+        'context_uuid'       : context_uuid,
+        'app_uuid'           : app_uuid,
+        'app_status'         : app_status,
+        'app_type'           : app_type,
+        'server_app_id'      : request.server_app_id,
+        'client_app_id'      : request.client_app_id,
+        'backing_qkdl_uuid'  : [qkdl_id.qkdl_uuid.uuid for qkdl_id in request.backing_qkdl_id],
+        'local_device_uuid'  : request.local_device_id.device_uuid.uuid,
+        'remote_device_uuid' : request.remote_device_id.device_uuid.uuid or None,
+        'created_at'         : now,
+        'updated_at'         : now,
+    }]
+
+
+    def callback(session : Session) -> Tuple[bool, List[Dict]]:
+        stmt = insert(AppModel).values(app_data)
+        stmt = stmt.on_conflict_do_update(
+            index_elements=[AppModel.app_uuid],
+            set_=dict(
+                app_status         = stmt.excluded.app_status,
+                app_type           = stmt.excluded.app_type,
+                server_app_id      = stmt.excluded.server_app_id,
+                client_app_id      = stmt.excluded.client_app_id,
+                backing_qkdl_uuid  = stmt.excluded.backing_qkdl_uuid,
+                local_device_uuid  = stmt.excluded.local_device_uuid,
+                remote_device_uuid = stmt.excluded.remote_device_uuid,
+                updated_at         = stmt.excluded.updated_at,
+            )
+        )
+        stmt = stmt.returning(AppModel.created_at, AppModel.updated_at)
+        created_at,updated_at = session.execute(stmt).fetchone()
+        updated = updated_at > created_at
+
+        return updated
+
+    updated = run_transaction(sessionmaker(bind=db_engine), callback)
+    context_id = json_context_id(context_uuid)
+    app_id = json_app_id(app_uuid, context_id=context_id)
+    #event_type = EventTypeEnum.EVENTTYPE_UPDATE if updated else EventTypeEnum.EVENTTYPE_CREATE
+    #notify_event_app(messagebroker, event_type, app_id)
+    #notify_event_context(messagebroker, EventTypeEnum.EVENTTYPE_UPDATE, context_id)
+    return AppId(**app_id)
+
+
+
+def app_get_by_server(db_engine : Engine, request : str) -> App:
+    def callback(session : Session) -> Optional[Dict]:
+        obj : Optional[AppModel] = session.query(AppModel)\
+            .filter_by(server_app_id=request).one_or_none()
+        return None if obj is None else obj.dump()
+    obj = run_transaction(sessionmaker(bind=db_engine), callback)
+    if obj is None:
+        raise NotFoundException('No app match found for', request)
+    return App(**obj)
+
+
+
+"""
+def device_delete(db_engine : Engine, messagebroker : MessageBroker, request : DeviceId) -> Empty:
+    device_uuid = device_get_uuid(request, allow_random=False)
+    def callback(session : Session) -> Tuple[bool, List[Dict]]:
+        query = session.query(TopologyDeviceModel)
+        query = query.filter_by(device_uuid=device_uuid)
+        topology_device_list : List[TopologyDeviceModel] = query.all()
+        topology_ids = [obj.topology.dump_id() for obj in topology_device_list]
+        num_deleted = session.query(DeviceModel).filter_by(device_uuid=device_uuid).delete()
+        return num_deleted > 0, topology_ids
+    deleted, updated_topology_ids = run_transaction(sessionmaker(bind=db_engine), callback)
+    device_id = json_device_id(device_uuid)
+    if deleted:
+        notify_event_device(messagebroker, EventTypeEnum.EVENTTYPE_REMOVE, device_id)
+
+        context_ids  : Dict[str, Dict] = dict()
+        topology_ids : Dict[str, Dict] = dict()
+        for topology_id in updated_topology_ids:
+            topology_uuid = topology_id['topology_uuid']['uuid']
+            topology_ids[topology_uuid] = topology_id
+            context_id = topology_id['context_id']
+            context_uuid = context_id['context_uuid']['uuid']
+            context_ids[context_uuid] = context_id
+
+        for topology_id in topology_ids.values():
+            notify_event_topology(messagebroker, EventTypeEnum.EVENTTYPE_UPDATE, topology_id)
+
+        for context_id in context_ids.values():
+            notify_event_context(messagebroker, EventTypeEnum.EVENTTYPE_UPDATE, context_id)
+
+    return Empty()
+
+def device_select(db_engine : Engine, request : DeviceFilter) -> DeviceList:
+    device_uuids = [
+        device_get_uuid(device_id, allow_random=False)
+        for device_id in request.device_ids.device_ids
+    ]
+    dump_params = dict(
+        include_endpoints   =request.include_endpoints,
+        include_config_rules=request.include_config_rules,
+        include_components  =request.include_components,
+    )
+    def callback(session : Session) -> List[Dict]:
+        query = session.query(DeviceModel)
+        if request.include_endpoints   : query = query.options(selectinload(DeviceModel.endpoints))
+        if request.include_config_rules: query = query.options(selectinload(DeviceModel.config_rules))
+        #if request.include_components  : query = query.options(selectinload(DeviceModel.components))
+        obj_list : List[DeviceModel] = query.filter(DeviceModel.device_uuid.in_(device_uuids)).all()
+        return [obj.dump(**dump_params) for obj in obj_list]
+    devices = run_transaction(sessionmaker(bind=db_engine), callback)
+    return DeviceList(devices=devices)
+"""
diff --git a/src/qkd_app/service/database/__init__.py b/src/qkd_app/service/database/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/service/database/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/service/database/models/QKDAppModel.py b/src/qkd_app/service/database/models/QKDAppModel.py
new file mode 100644
index 0000000000000000000000000000000000000000..c32b4e28c95105d8659cb52790f51b330764c2cf
--- /dev/null
+++ b/src/qkd_app/service/database/models/QKDAppModel.py
@@ -0,0 +1,63 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 operator
+from sqlalchemy import CheckConstraint, Column, DateTime, Float, Enum, ForeignKey, Integer, String
+from sqlalchemy.dialects.postgresql import UUID, ARRAY
+from sqlalchemy.orm import relationship
+from typing import Dict
+from ._Base import _Base
+from .enums.QKDAppStatus import ORM_QKDAppStatusEnum
+from .enums.QKDAppTypes import ORM_QKDAppTypesEnum
+
+class AppModel(_Base):
+    __tablename__ = 'qkd_app'
+
+    app_uuid            = Column(UUID(as_uuid=False), primary_key=True)
+    context_uuid        = Column(UUID(as_uuid=False), nullable=False) # Supposed to be Foreign Key
+    app_status          = Column(Enum(ORM_QKDAppStatusEnum), nullable=False)
+    app_type            = Column(Enum(ORM_QKDAppTypesEnum), nullable=False)
+    server_app_id       = Column(String, nullable=False)
+    client_app_id       = Column(ARRAY(String), nullable=False)
+    backing_qkdl_uuid   = Column(ARRAY(UUID(as_uuid=False)), nullable=False)
+    local_device_uuid   = Column(UUID(as_uuid=False), nullable=False)
+    remote_device_uuid  = Column(UUID(as_uuid=False), nullable=True)
+
+    # Optare: Created_at and Updated_at are only used to know if an app was updated later on the code. Don't change it
+
+    created_at          = Column(DateTime, nullable=False)
+    updated_at          = Column(DateTime, nullable=False)
+
+    #__table_args__ = (
+    #    CheckConstraint(... >= 0, name='name_value_...'),
+    #)
+
+    def dump_id(self) -> Dict:
+        return {
+            'context_id': {'context_uuid': {'uuid': self.context_uuid}},
+            'app_uuid': {'uuid': self.app_uuid}
+        }
+
+    def dump(self) -> Dict:
+        result = {
+            'app_id'           : self.dump_id(),
+            'app_status'       : self.app_status.value,
+            'app_type'         : self.app_type.value,
+            'server_app_id'    : self.server_app_id,
+            'client_app_id'    : self.client_app_id,
+            'backing_qkdl_id'  : [{'qkdl_uuid': {'uuid': qkdl_id}} for qkdl_id in self.backing_qkdl_uuid],
+            'local_device_id'  : {'device_uuid': {'uuid': self.local_device_uuid}},
+            'remote_device_id' : {'device_uuid': {'uuid': self.remote_device_uuid}},
+        }
+        return result
diff --git a/src/qkd_app/service/database/models/_Base.py b/src/qkd_app/service/database/models/_Base.py
new file mode 100644
index 0000000000000000000000000000000000000000..51863e1d5c06a875c298eab726cfdc3b7fcb75ca
--- /dev/null
+++ b/src/qkd_app/service/database/models/_Base.py
@@ -0,0 +1,44 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 sqlalchemy
+from typing import Any, List
+from sqlalchemy.orm import Session, sessionmaker, declarative_base
+from sqlalchemy.sql import text
+from sqlalchemy_cockroachdb import run_transaction
+
+_Base = declarative_base()
+
+'''
+def create_performance_enhancers(db_engine : sqlalchemy.engine.Engine) -> None:
+    def index_storing(
+        index_name : str, table_name : str, index_fields : List[str], storing_fields : List[str]
+    ) -> Any:
+        str_index_fields = ','.join(['"{:s}"'.format(index_field) for index_field in index_fields])
+        str_storing_fields = ','.join(['"{:s}"'.format(storing_field) for storing_field in storing_fields])
+        INDEX_STORING = 'CREATE INDEX IF NOT EXISTS {:s} ON "{:s}" ({:s}) STORING ({:s});'
+        return text(INDEX_STORING.format(index_name, table_name, str_index_fields, str_storing_fields))
+
+    statements = [
+        # In case of relations
+    ]
+    def callback(session : Session) -> bool:
+        for stmt in statements: session.execute(stmt)
+    run_transaction(sessionmaker(bind=db_engine), callback)
+'''
+
+def rebuild_database(db_engine : sqlalchemy.engine.Engine, drop_if_exists : bool = False):
+    if drop_if_exists: _Base.metadata.drop_all(db_engine)
+    _Base.metadata.create_all(db_engine)
+    #create_performance_enhancers(db_engine)
diff --git a/src/qkd_app/service/database/models/__init__.py b/src/qkd_app/service/database/models/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/service/database/models/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/service/database/models/enums/QKDAppStatus.py b/src/qkd_app/service/database/models/enums/QKDAppStatus.py
new file mode 100644
index 0000000000000000000000000000000000000000..d3063ef56704ce1bdd48d15ea8c6486ed7c8cfae
--- /dev/null
+++ b/src/qkd_app/service/database/models/enums/QKDAppStatus.py
@@ -0,0 +1,27 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 enum, functools
+from common.proto.qkd_app_pb2 import QKDAppStatusEnum
+from ._GrpcToEnum import grpc_to_enum
+
+class ORM_QKDAppStatusEnum(enum.Enum):
+    ON           = QKDAppStatusEnum.QKDAPPSTATUS_ON
+    DISCONNECTED = QKDAppStatusEnum.QKDAPPSTATUS_DISCONNECTED
+    OUT_OF_TIME  = QKDAppStatusEnum.QKDAPPSTATUS_OUT_OF_TIME
+    ZOMBIE       = QKDAppStatusEnum.QKDAPPSTATUS_ZOMBIE
+
+
+grpc_to_enum__qkd_app_status = functools.partial(
+    grpc_to_enum, QKDAppStatusEnum, ORM_QKDAppStatusEnum)
diff --git a/src/qkd_app/service/database/models/enums/QKDAppTypes.py b/src/qkd_app/service/database/models/enums/QKDAppTypes.py
new file mode 100644
index 0000000000000000000000000000000000000000..f50b8982d80c0af97c2cbd96d336f450afc50f9b
--- /dev/null
+++ b/src/qkd_app/service/database/models/enums/QKDAppTypes.py
@@ -0,0 +1,25 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 enum, functools
+from common.proto.qkd_app_pb2 import QKDAppTypesEnum
+from ._GrpcToEnum import grpc_to_enum
+
+class ORM_QKDAppTypesEnum(enum.Enum):
+    INTERNAL = QKDAppTypesEnum.QKDAPPTYPES_INTERNAL
+    CLIENT   = QKDAppTypesEnum.QKDAPPTYPES_CLIENT
+
+
+grpc_to_enum__qkd_app_types = functools.partial(
+    grpc_to_enum, QKDAppTypesEnum, ORM_QKDAppTypesEnum)
diff --git a/src/qkd_app/service/database/models/enums/_GrpcToEnum.py b/src/qkd_app/service/database/models/enums/_GrpcToEnum.py
new file mode 100644
index 0000000000000000000000000000000000000000..0dcad039f7be240acbbec418d12475557e4c42c1
--- /dev/null
+++ b/src/qkd_app/service/database/models/enums/_GrpcToEnum.py
@@ -0,0 +1,38 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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 re
+from enum import Enum
+from typing import Optional
+
+# Enumeration classes are redundant with gRPC classes, but gRPC does not provide a programmatical method to retrieve
+# the values it expects from strings containing the desired value symbol or its integer value, so a kind of mapping is
+# required. Besides, ORM Models expect Enum classes in EnumeratedFields; we create specific and conveniently defined
+# Enum classes to serve both purposes.
+
+def grpc_to_enum(grpc_enum_class, orm_enum_class : Enum, grpc_enum_value, grpc_enum_prefix : Optional[str] = None):
+    enum_name = grpc_enum_class.Name(grpc_enum_value)
+
+    if grpc_enum_prefix is None:
+        grpc_enum_prefix = orm_enum_class.__name__.upper()
+        #grpc_enum_prefix = re.sub(r'^ORM_(.+)$', r'\1', grpc_enum_prefix)
+        #grpc_enum_prefix = re.sub(r'^(.+)ENUM$', r'\1', grpc_enum_prefix)
+        #grpc_enum_prefix = grpc_enum_prefix + '_'
+        grpc_enum_prefix = re.sub(r'^ORM_(.+)ENUM$', r'\1_', grpc_enum_prefix)
+
+    if len(grpc_enum_prefix) > 0:
+        enum_name = enum_name.replace(grpc_enum_prefix, '')
+
+    orm_enum_value = orm_enum_class._member_map_.get(enum_name)
+    return orm_enum_value
diff --git a/src/qkd_app/service/database/models/enums/__init__.py b/src/qkd_app/service/database/models/enums/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/service/database/models/enums/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/service/database/uuids/QKDApp.py b/src/qkd_app/service/database/uuids/QKDApp.py
new file mode 100644
index 0000000000000000000000000000000000000000..175f1d5f3cf4ceda12a022b4afadb376e11ae5a5
--- /dev/null
+++ b/src/qkd_app/service/database/uuids/QKDApp.py
@@ -0,0 +1,30 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
+
+from common.proto.qkd_app_pb2 import AppId
+from common.method_wrappers.ServiceExceptions import InvalidArgumentsException
+from ._Builder import get_uuid_from_string, get_uuid_random
+
+def app_get_uuid(
+    app_id : AppId, allow_random : bool = False
+) -> str:
+    app_uuid = app_id.app_uuid.uuid
+
+    if len(app_uuid) > 0:
+        return get_uuid_from_string(app_uuid)
+    if allow_random: return get_uuid_random()
+
+    raise InvalidArgumentsException([
+        ('app_id.app_uuid.uuid', app_uuid),
+    ], extra_details=['At least one is required to produce a App UUID'])
diff --git a/src/qkd_app/service/database/uuids/_Builder.py b/src/qkd_app/service/database/uuids/_Builder.py
new file mode 100644
index 0000000000000000000000000000000000000000..39c98de69d577ce2722693e57c4ee678124f9e30
--- /dev/null
+++ b/src/qkd_app/service/database/uuids/_Builder.py
@@ -0,0 +1,44 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
+
+from typing import Optional, Union
+from uuid import UUID, uuid4, uuid5
+
+# Generate a UUIDv5-like from the SHA-1 of "TFS" and no namespace to be used as the NAMESPACE for all
+# the context UUIDs generated. For efficiency purposes, the UUID is hardcoded; however, it is produced
+# using the following code:
+#    from hashlib import sha1
+#    from uuid import UUID
+#    hash = sha1(bytes('TFS', 'utf-8')).digest()
+#    NAMESPACE_TFS = UUID(bytes=hash[:16], version=5)
+NAMESPACE_TFS = UUID('200e3a1f-2223-534f-a100-758e29c37f40')
+
+def get_uuid_from_string(str_uuid_or_name : Union[str, UUID], prefix_for_name : Optional[str] = None) -> str:
+    # if UUID given, assume it is already a valid UUID
+    if isinstance(str_uuid_or_name, UUID): return str_uuid_or_name
+    if not isinstance(str_uuid_or_name, str):
+        MSG = 'Parameter({:s}) cannot be used to produce a UUID'
+        raise Exception(MSG.format(str(repr(str_uuid_or_name))))
+    try:
+        # try to parse as UUID
+        return str(UUID(str_uuid_or_name))
+    except: # pylint: disable=bare-except
+        # produce a UUID within TFS namespace from parameter
+        if prefix_for_name is not None:
+            str_uuid_or_name = '{:s}/{:s}'.format(prefix_for_name, str_uuid_or_name)
+        return str(uuid5(NAMESPACE_TFS, str_uuid_or_name))
+
+def get_uuid_random() -> str:
+    # Generate random UUID. No need to use namespace since "namespace + random = random".
+    return str(uuid4())
diff --git a/src/qkd_app/service/rest_server/RestServer.py b/src/qkd_app/service/rest_server/RestServer.py
new file mode 100644
index 0000000000000000000000000000000000000000..4302a0562337ad9af8c28ef037d4fb64ec1e53bf
--- /dev/null
+++ b/src/qkd_app/service/rest_server/RestServer.py
@@ -0,0 +1,23 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
+
+from common.Constants import ServiceNameEnum
+from common.Settings import get_service_baseurl_http, get_service_port_http
+from common.tools.service.GenericRestServer import GenericRestServer
+
+class RestServer(GenericRestServer):
+    def __init__(self, cls_name: str = __name__) -> None:
+        bind_port = get_service_port_http(ServiceNameEnum.APP)
+        base_url = get_service_baseurl_http(ServiceNameEnum.APP)
+        super().__init__(bind_port, base_url, cls_name=cls_name)
diff --git a/src/qkd_app/service/rest_server/__init__.py b/src/qkd_app/service/rest_server/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..07d08814021ef82220611ee21c01ba01806682e9
--- /dev/null
+++ b/src/qkd_app/service/rest_server/__init__.py
@@ -0,0 +1,13 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
diff --git a/src/qkd_app/service/rest_server/qkd_app/Resources.py b/src/qkd_app/service/rest_server/qkd_app/Resources.py
new file mode 100644
index 0000000000000000000000000000000000000000..6ba79d3940da91dfebc1a1c666893548caccbe6c
--- /dev/null
+++ b/src/qkd_app/service/rest_server/qkd_app/Resources.py
@@ -0,0 +1,86 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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, json
+from flask import request
+from flask_restful import Resource
+from common.proto.context_pb2 import Empty
+from common.proto.qkd_app_pb2 import App, QKDAppTypesEnum
+from common.Constants import DEFAULT_CONTEXT_NAME
+from context.client.ContextClient import ContextClient
+from qkd_app.client.QKDAppClient import QKDAppClient
+
+
+class _Resource(Resource):
+    def __init__(self) -> None:
+        super().__init__()
+        self.context_client = ContextClient()
+        self.qkd_app_client = QKDAppClient()
+
+class Index(_Resource):
+    def get(self):
+        return {'hello': 'world'}
+
+class CreateQKDApp(_Resource):
+    # Optare: Post request for the QKD Node to call the TeraflowSDN. Example of requests below
+    def post(self):
+        app = request.get_json()['app']
+
+        devices = self.context_client.ListDevices(Empty())
+        devices = devices.devices
+
+        local_device = None
+
+
+        # This for-loop won't be necessary if we can garantee Device ID is the same as QKDN Id
+        for device in devices:
+            for config_rule in device.device_config.config_rules:
+                if config_rule.custom.resource_key == '__node__':
+                    value = json.loads(config_rule.custom.resource_value)
+                    qkdn_id = value['qkdn_id']
+                    if app['local_qkdn_id'] == qkdn_id:
+                        local_device = device
+                    break
+
+        # Optare: Todo:  Verify that a service is present for this app
+        '''
+        requests.post('http://10.211.36.220/app/create_qkd_app', json={'app': {'server_app_id':'1', 'client_app_id':[], 'app_status':'ON', 'local_qkdn_id':'00000001-0000-0000-0000-000000000000', 'backing_qkdl_id':['00000003-0002-0000-0000-000000000000']}})
+
+
+        requests.post('http://10.211.36.220/app/create_qkd_app', json={'app': {'server_app_id':'1', 'client_app_id':[], 'app_status':'ON', 'local_qkdn_id':'00000003-0000-0000-0000-000000000000', 'backing_qkdl_id':['00000003-0002-0000-0000-000000000000']}})
+        '''
+        
+
+        if local_device is None:
+            return {"status": "fail"}
+
+        external_app_src_dst = {
+            'app_id': {'context_id': {'context_uuid': {'uuid': DEFAULT_CONTEXT_NAME}}, 'app_uuid': {'uuid': ''}},
+            'app_status': 'QKDAPPSTATUS_' + app['app_status'],
+            'app_type': QKDAppTypesEnum.QKDAPPTYPES_CLIENT,
+            'server_app_id': app['server_app_id'],
+            'client_app_id': app['client_app_id'],
+            'backing_qkdl_id': [{'qkdl_uuid': {'uuid': qkdl_id}} for qkdl_id in app['backing_qkdl_id']],
+            'local_device_id': local_device.device_id,
+            'remote_device_id': {'device_uuid': {'uuid': ''}},
+        }
+
+
+        # Optare: This will call our internal RegisterApp which supports the creation of both internal and external app.
+        # Optare the verification for knowing if two parties are requesting the same app is done inside RegisterApp's function
+        self.qkd_app_client.RegisterApp(App(**external_app_src_dst))
+
+        # Optare: Todo: Communicate by SBI with both Nodes of the new App
+
+        return {"status": "success"}
diff --git a/src/qkd_app/service/rest_server/qkd_app/__init__.py b/src/qkd_app/service/rest_server/qkd_app/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..6fc23b371414dcb2bac4afde63524febf71e5337
--- /dev/null
+++ b/src/qkd_app/service/rest_server/qkd_app/__init__.py
@@ -0,0 +1,30 @@
+# Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/)
+#
+# 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.
+
+from qkd_app.service.rest_server.RestServer import RestServer
+from .Resources import (
+    CreateQKDApp, Index)
+
+URL_PREFIX = '/qkd_app'
+
+# Use 'path' type since some identifiers might contain char '/' and Flask is unable to recognize them in 'string' type.
+RESOURCES = [
+    # (endpoint_name, resource_class, resource_url)
+    ('api.index',    Index,    '/'),
+    ('api.register_qkd_app',    CreateQKDApp,    '/create_qkd_app'),
+]
+
+def register_qkd_app(app_server : RestServer):
+    for endpoint_name, resource_class, resource_url in RESOURCES:
+        app_server.add_resource(resource_class, URL_PREFIX + resource_url, endpoint=endpoint_name)
diff --git a/src/service/Dockerfile b/src/service/Dockerfile
index a847ae762d1303dda852d7f3d8200d3db3ef53f7..6f23f0a89387e2db3802ee20e003ccb6482844ff 100644
--- a/src/service/Dockerfile
+++ b/src/service/Dockerfile
@@ -70,6 +70,8 @@ COPY src/pathcomp/frontend/__init__.py pathcomp/frontend/__init__.py
 COPY src/pathcomp/frontend/client/. pathcomp/frontend/client/
 COPY src/e2e_orchestrator/__init__.py e2e_orchestrator/__init__.py
 COPY src/e2e_orchestrator/client/. e2e_orchestrator/client/
+COPY src/qkd_app/__init__.py qkd_app/__init__.py
+COPY src/qkd_app/client/. qkd_app/client/
 COPY src/service/. service/
 
 # Start the service
diff --git a/src/service/service/__main__.py b/src/service/service/__main__.py
index ae8a9e960cf6a0d720b508fe3ea5592632420c18..5f9f2fa3afb2b708068423f70f764ffc61d29d9c 100644
--- a/src/service/service/__main__.py
+++ b/src/service/service/__main__.py
@@ -44,6 +44,8 @@ def main():
         get_env_var_name(ServiceNameEnum.DEVICE,   ENVVAR_SUFIX_SERVICE_PORT_GRPC),
         get_env_var_name(ServiceNameEnum.PATHCOMP, ENVVAR_SUFIX_SERVICE_HOST     ),
         get_env_var_name(ServiceNameEnum.PATHCOMP, ENVVAR_SUFIX_SERVICE_PORT_GRPC),
+        get_env_var_name(ServiceNameEnum.QKD_APP,  ENVVAR_SUFIX_SERVICE_HOST     ),
+        get_env_var_name(ServiceNameEnum.QKD_APP,  ENVVAR_SUFIX_SERVICE_PORT_GRPC),
     ])
 
     signal.signal(signal.SIGINT,  signal_handler)
diff --git a/src/service/service/task_scheduler/TaskExecutor.py b/src/service/service/task_scheduler/TaskExecutor.py
index cd20faad23a06678be39dbacc476a0ea25d4d540..cb27993702963b4aac88ec04eca2a1c796d0c364 100644
--- a/src/service/service/task_scheduler/TaskExecutor.py
+++ b/src/service/service/task_scheduler/TaskExecutor.py
@@ -20,6 +20,7 @@ from common.proto.context_pb2 import (
     Connection, ConnectionId, Device, DeviceDriverEnum, DeviceId, Service, ServiceId,
     OpticalConfig, OpticalConfigId
 )
+from common.proto.qkd_app_pb2 import App
 from common.tools.context_queries.Connection import get_connection_by_id
 from common.tools.context_queries.Device import get_device
 from common.tools.context_queries.Service import get_service_by_id
@@ -27,11 +28,12 @@ from common.tools.grpc.Tools import grpc_message_to_json_string
 from common.tools.object_factory.Device import json_device_id
 from context.client.ContextClient import ContextClient
 from device.client.DeviceClient import DeviceClient
+from qkd_app.client.QKDAppClient import QKDAppClient
 from service.service.service_handler_api.Exceptions import (
     UnsatisfiedFilterException, UnsupportedFilterFieldException, UnsupportedFilterFieldValueException
 )
 from service.service.service_handler_api.ServiceHandlerFactory import ServiceHandlerFactory, get_service_handler_class
-from service.service.tools.ObjectKeys import get_connection_key, get_device_key, get_service_key
+from service.service.tools.ObjectKeys import get_connection_key, get_device_key, get_service_key, get_app_key
 
 if TYPE_CHECKING:
     from service.service.service_handler_api._ServiceHandler import _ServiceHandler
@@ -44,11 +46,14 @@ class CacheableObjectType(Enum):
     CONNECTION = 'connection'
     DEVICE     = 'device'
     SERVICE    = 'service'
+    QKD_APP    = 'qkd-app'
 
 class TaskExecutor:
     def __init__(self, service_handler_factory : ServiceHandlerFactory) -> None:
         self._service_handler_factory = service_handler_factory
         self._context_client = ContextClient()
+        # DEPENDENCY QKD
+        self._qkd_app_client = QKDAppClient()
         self._device_client = DeviceClient()
         self._grpc_objects_cache : Dict[str, CacheableObject] = dict()
 
@@ -220,3 +225,12 @@ class TaskExecutor:
                     str(dict_connection_devices)
                 )
             )
+
+
+    # ----- QkdApp-related methods -------------------------------------------------------------------------------------
+
+    def register_app(self, app: App) -> None:
+        app_key = get_app_key(app.app_id)
+        self._qkd_app_client.RegisterApp(app)
+        LOGGER.info("reg registered")
+        self._store_grpc_object(CacheableObjectType.QKD_APP, app_key, app)
diff --git a/src/service/service/tools/ObjectKeys.py b/src/service/service/tools/ObjectKeys.py
index f45126e07df6a74a20e507fd51d08f1a32de7f98..cfc719bba736a4ea0789b028a97ca267b2d04089 100644
--- a/src/service/service/tools/ObjectKeys.py
+++ b/src/service/service/tools/ObjectKeys.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from common.proto.context_pb2 import ConnectionId, DeviceId, ServiceId
+from common.proto.qkd_app_pb2 import AppId
 
 def get_connection_key(connection_id : ConnectionId) -> str:
     return connection_id.connection_uuid.uuid
@@ -24,3 +25,7 @@ def get_service_key(service_id : ServiceId) -> str:
     context_uuid = service_id.context_id.context_uuid.uuid
     service_uuid = service_id.service_uuid.uuid
     return '{:s}/{:s}'.format(context_uuid, service_uuid)
+
+def get_app_key(app_id : AppId) -> str:
+    return app_id.app_uuid.uuid
+
diff --git a/src/webui/service/templates/service/configure_QKD.html b/src/webui/service/templates/service/configure_QKD.html
index 4f3da37dab3a47f04d657d8501be8e3d834c4718..a01f4519d7f4b09732fba6d24db034f143be9943 100644
--- a/src/webui/service/templates/service/configure_QKD.html
+++ b/src/webui/service/templates/service/configure_QKD.html
@@ -1,5 +1,5 @@
 <!--
- Copyright 2022-2023 ETSI TeraFlowSDN - TFS OSG (https://tfs.etsi.org/)
+ Copyright 2022-2024 ETSI OSG/SDG TeraFlowSDN (TFS) (https://tfs.etsi.org/) 
 
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.