diff --git a/wis2-grep-api/wis2_grep.py b/wis2-grep-api/wis2_grep.py
index 005aa34..8b71d20 100644
--- a/wis2-grep-api/wis2_grep.py
+++ b/wis2-grep-api/wis2_grep.py
@@ -30,20 +30,30 @@
 import json
 import logging
 import os
-import requests
+import uuid
 
 from pywis_pubsub.mqtt import MQTTPubSubClient
+import requests
 
 from pygeoapi.process.base import BaseProcessor, ProcessorExecuteError
 
 API_ENDPOINT = 'http://localhost/collections/wis2-notification-messages/items'
 
 BROKER_URL = os.environ['WIS2_GREP_BROKER_URL']
+CENTRE_ID = os.environ['WIS2_GREP_CENTRE_ID']
 
 MQTT_CLIENT = MQTTPubSubClient(BROKER_URL)
 
 LOGGER = logging.getLogger(__name__)
 
+GB_LINKS = []
+
+for key, value in os.environ.items():
+    if key.startswith('WIS2_GREP_GB_LINK'):
+        # centre_id, url, title = value.rsplit(',', 2)
+        GB_LINKS.append(value.split(',', 2))
+
+
 #: Process metadata and description
 PROCESS_METADATA = {
     'version': '0.1.0',
@@ -96,9 +106,10 @@
         },
         'subscriber-id': {
             'title': 'Subscriber id',
-            'description': 'identifier of subscribe, used in response topic',
+            'description': 'UUID of subscriber, used in response topic',
             'schema': {
-                'type': 'string'
+                'type': 'string',
+                'format': 'uuid'
             },
             'minOccurs': 1,
             'maxOccurs': 1,
@@ -117,32 +128,35 @@
                         'type': 'string',
                         'description': 'Result of subscription request'
                     },
-                    'subscription': {
-                        'type': 'object',
-                        'required': [
-                            'href',
-                            'rel'
-                        ],
-                        'properties': {
-                            'href': {
-                                'type': 'string',
-                                'example': 'http://data.example.com/buildings/123'  # noqa
-                            },
-                            'rel': {
-                                'type': 'string',
-                                'example': 'alternate'
-                            },
-                            'type': {
-                                'type': 'string',
-                                'example': 'application/geo+json'
-                            },
-                            'title': {
-                                'type': 'string',
-                                'example': 'Trierer Strasse 70, 53115 Bonn'
-                            },
-                            'channel': {
-                                'type': 'string',
-                                'description': 'topic to subscribe to for broker workflow'  # noqa
+                    'subscriptions': {
+                        'type': 'array',
+                        'items': {
+                            'type': 'object',
+                            'required': [
+                                'href',
+                                'rel'
+                            ],
+                            'properties': {
+                                'href': {
+                                    'type': 'string',
+                                    'example': 'http://data.example.com/buildings/123'  # noqa
+                                },
+                                'rel': {
+                                    'type': 'string',
+                                    'example': 'alternate'
+                                },
+                                'type': {
+                                    'type': 'string',
+                                    'example': 'application/geo+json'
+                                },
+                                'title': {
+                                    'type': 'string',
+                                    'example': 'Trierer Strasse 70, 53115 Bonn'
+                                },
+                                'channel': {
+                                    'type': 'string',
+                                    'description': 'topic to subscribe to for broker workflow'  # noqa
+                                }
                             }
                         }
                     }
@@ -154,7 +168,7 @@
         'inputs': {
             'topic': 'origin/a/wis2/fr-meteofrance',
             'datetime': '2024-06-10T03:00:00Z/2024-06-10T06:00:00Z',
-            'subscriber-id': 'foobar123'
+            'subscriber-id': 'a30c829b-0ee3-4e4f-bc1f-1f784465b20e'
         }
     }
 }
@@ -180,21 +194,32 @@ def execute(self, data):
         topic = data.get('topic')
         subscriber_id = data.get('subscriber-id')
 
+        LOGGER.debug('Sanitizing topic')
+        api_topic = topic.replace('/#', '').replace('+', '*')
+
         if None in [datetime_, topic, subscriber_id]:
             msg = 'datetime/topic/subscriber-id required'
+            LOGGER.error(msg)
             raise ProcessorExecuteError(msg)
 
+        try:
+            LOGGER.debug('Validating subscriber-id')
+            uuid.UUID(subscriber_id)
+        except ValueError:
+            raise ProcessorExecuteError('Invalid UUID')
+
         outputs = {}
-        pub_topic = f'replay/a/wis2/{subscriber_id}'
+        pub_topic = f'replay/a/wis2/{CENTRE_ID}/{subscriber_id}'
 
         api_params = {
             # 'datetime': datetime_
-            'topic': topic,
+            'topic': api_topic,
         }
 
         try:
-            r = requests.get(API_ENDPOINT, params=api_params).json()
+            r = requests.get(API_ENDPOINT, params=api_params)
             r.raise_for_status()
+            r = r.json()
         except requests.exceptions.HTTPError as err:
             LOGGER.error(err)
             outputs['status'] = 'failed'
@@ -202,13 +227,16 @@ def execute(self, data):
             return 'application/json', outputs
 
         outputs['status'] = 'successful'
-        outputs['subscription'] = {
-            'rel': 'items',
-            'type': 'application/geo+json',
-            'href': BROKER_URL,
-            'title': 'User-defined notifications',
-            'channel': pub_topic
-        }
+        outputs['subscriptions'] = []
+
+        for gb_link in GB_LINKS:
+            outputs['subscriptions'].append({
+                'rel': 'items',
+                'type': 'application/geo+json',
+                'href': gb_link[1],
+                'title': gb_link[2],
+                'channel': pub_topic
+            })
 
         for feature in r['features']:
             MQTT_CLIENT.pub(pub_topic, json.dumps(feature))
diff --git a/wis2-grep.env b/wis2-grep.env
index 9c2cb40..8fc62d5 100644
--- a/wis2-grep.env
+++ b/wis2-grep.env
@@ -6,3 +6,9 @@ export WIS2_GREP_BACKEND_CONNECTION=http://wis2-grep-backend:9200/wis2-notificat
 export WIS2_GREP_BROKER_URL=mqtt://wis2-grep:wis2-grep@wis2-grep-broker:1883
 export WIS2_GREP_CENTRE_ID=ca-eccc-msc-global-replay
 export WIS2_GREP_GB=mqtts://everyone:everyone@globalbroker.meteo.fr:8883
+
+# global broker links
+export WIS2_GREP_GB_LINK_METEOFRANCE="fr-meteo-france-global-broker,mqtts://everyone:everyone@globalbroker.meteo.fr:8883,Météo-France, Global Broker Service"
+export WIS2_GREP_GB_LINK_CMA="cn-cma-global-broker,mqtts://everyone:everyone@gb.wis.cma.cn:8883,China Meteorological Agency, Global Broker Service"
+export WIS2_GREP_GB_LINK_NOAA="us-noaa-nws-global-broker,mqtts://everyone:everyone@wis2globalbroker.nws.noaa.gov:8883,National Oceanic and Atmospheric Administration, National Weather Service, Global Broker Service"
+export WIS2_GREP_GB_LINK_INMET="br-inmet-global-broker,mqtts://everyone:everyone@globalbroker.inmet.gov.br:8883,Instituto Nacional de Meteorologia (Brazil), Global Broker Service"