diff --git a/selfprivacy_api/graphql/queries/monitoring.py b/selfprivacy_api/graphql/queries/monitoring.py
index 1ae2498..637dc2a 100644
--- a/selfprivacy_api/graphql/queries/monitoring.py
+++ b/selfprivacy_api/graphql/queries/monitoring.py
@@ -1,5 +1,6 @@
 import strawberry
 from typing import Optional
+from datetime import datetime
 from selfprivacy_api.utils.prometheus import PrometheusQueries, PrometheusQueryResult
 
 
@@ -8,8 +9,8 @@ class Monitoring:
     @strawberry.field
     def disk_usage(
         self,
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,
     ) -> PrometheusQueryResult:
         return PrometheusQueries.disk_usage(start, end, step)
@@ -17,8 +18,8 @@ class Monitoring:
     @strawberry.field
     def memory_usage(
         self,
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,
     ) -> PrometheusQueryResult:
         return PrometheusQueries.memory_usage(start, end, step)
@@ -26,8 +27,8 @@ class Monitoring:
     @strawberry.field
     def cpu_usage(
         self,
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,
     ) -> PrometheusQueryResult:
         return PrometheusQueries.cpu_usage(start, end, step)
diff --git a/selfprivacy_api/utils/prometheus.py b/selfprivacy_api/utils/prometheus.py
index 23e7958..279511b 100644
--- a/selfprivacy_api/utils/prometheus.py
+++ b/selfprivacy_api/utils/prometheus.py
@@ -22,14 +22,14 @@ class PrometheusQueryResult:
 
 class PrometheusQueries:
     @staticmethod
-    def _send_query(query: str, start: int, end: int, step: int):
+    def _send_query(query: str, start: datetime, end: datetime, step: int):
         try:
             response = requests.get(
                 f"{PROMETHEUS_URL}/api/v1/query_range",
                 params={
                     "query": query,
-                    "start": start,
-                    "end": end,
+                    "start": int(start.timestamp()),
+                    "end": int(start.timestamp()),
                     "step": step,
                 },
             )
@@ -47,26 +47,26 @@ class PrometheusQueries:
 
     @staticmethod
     def cpu_usage(
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,  # seconds
     ) -> PrometheusQueryResult:
         """
         Get CPU information.
 
         Args:
-            start (int, optional): Unix timestamp indicating the start time.
+            start (int, optional): Unix timestamp (in seconds) indicating the start time.
                 Defaults to 20 minutes ago if not provided.
-            end (int, optional): Unix timestamp indicating the end time.
+            end (int, optional): Unix timestamp (in seconds) indicating the end time.
                 Defaults to current time if not provided.
             step (int): Interval in seconds for querying disk usage data.
         """
 
         if not start:
-            start = int((datetime.now() - timedelta(minutes=20)).timestamp())
+            start = datetime.now() - timedelta(minutes=20)
 
         if not end:
-            end = int(datetime.now().timestamp())
+            end = datetime.now()
 
         query = '100 - (avg by (instance) (rate(node_cpu_seconds_total{mode="idle"}[5m])) * 100)'
 
@@ -74,8 +74,8 @@ class PrometheusQueries:
 
     @staticmethod
     def memory_usage(
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,  # seconds
     ) -> PrometheusQueryResult:
         """
@@ -90,10 +90,10 @@ class PrometheusQueries:
         """
 
         if not start:
-            start = int((datetime.now() - timedelta(minutes=20)).timestamp())
+            start = datetime.now() - timedelta(minutes=20)
 
         if not end:
-            end = int(datetime.now().timestamp())
+            end = datetime.now()
 
         query = "100 - (100 * (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes))"
 
@@ -101,8 +101,8 @@ class PrometheusQueries:
 
     @staticmethod
     def disk_usage(
-        start: Optional[int] = None,
-        end: Optional[int] = None,
+        start: Optional[datetime] = None,
+        end: Optional[datetime] = None,
         step: int = 60,  # seconds
     ) -> PrometheusQueryResult:
         """
@@ -117,10 +117,10 @@ class PrometheusQueries:
         """
 
         if not start:
-            start = int((datetime.now() - timedelta(minutes=20)).timestamp())
+            start = datetime.now() - timedelta(minutes=20)
 
         if not end:
-            end = int(datetime.now().timestamp())
+            end = datetime.now()
 
         query = '100 - (100 * ((node_filesystem_avail_bytes{mountpoint="/",fstype!="rootfs"} )  / (node_filesystem_size_bytes{mountpoint="/",fstype!="rootfs"}) ))'
 
diff --git a/tests/test_graphql/test_api_monitoring.py b/tests/test_graphql/test_api_monitoring.py
index 0d386a2..69cb781 100644
--- a/tests/test_graphql/test_api_monitoring.py
+++ b/tests/test_graphql/test_api_monitoring.py
@@ -2,6 +2,7 @@
 # pylint: disable=unused-argument
 # pylint: disable=missing-function-docstring
 
+from datetime import datetime
 import pytest
 
 from selfprivacy_api.utils.prometheus import PrometheusQueryResult
@@ -68,7 +69,7 @@ def generate_mock_query(name):
 
 def generate_mock_query_with_options(name):
     return f"""
-    query Query($start: Int, $end: Int, $step: Int) {{
+    query Query($start: DateTime, $end: DateTime, $step: Int) {{
         monitoring {{
             {name}(start: $start, end: $end, step: $step) {{ resultType, result }}
         }}
@@ -131,8 +132,8 @@ def test_graphql_get_disk_usage_with_options(
         json={
             "query": generate_mock_query_with_options("diskUsage"),
             "variables": {
-                "start": 1720136108,
-                "end": 1720137319,
+                "start": datetime.fromtimestamp(1720136108).isoformat(),
+                "end": datetime.fromtimestamp(1720137319).isoformat(),
                 "step": 90,
             },
         },
@@ -168,8 +169,8 @@ def test_graphql_get_memory_usage_with_options(
         json={
             "query": generate_mock_query_with_options("memoryUsage"),
             "variables": {
-                "start": 1720136108,
-                "end": 1720137319,
+                "start": datetime.fromtimestamp(1720136108).isoformat(),
+                "end": datetime.fromtimestamp(1720137319).isoformat(),
                 "step": 90,
             },
         },
@@ -203,8 +204,8 @@ def test_graphql_get_cpu_usage_with_options(client, authorized_client, mock_cpu_
         json={
             "query": generate_mock_query_with_options("cpuUsage"),
             "variables": {
-                "start": 1720136108,
-                "end": 1720137319,
+                "start": datetime.fromtimestamp(1720136108).isoformat(),
+                "end": datetime.fromtimestamp(1720137319).isoformat(),
                 "step": 90,
             },
         },