diff --git a/bugsink/api_serializers.py b/bugsink/api_serializers.py
new file mode 100644
index 0000000..d50f8da
--- /dev/null
+++ b/bugsink/api_serializers.py
@@ -0,0 +1,13 @@
+import datetime
+from rest_framework import serializers
+
+
+class UTCModelSerializer(serializers.ModelSerializer):
+
+    def build_standard_field(self, field_name, model_field):
+        field_class, field_kwargs = super().build_standard_field(field_name, model_field)
+
+        if field_class is serializers.DateTimeField:
+            field_kwargs.setdefault("default_timezone", datetime.timezone.utc)
+
+        return field_class, field_kwargs
diff --git a/events/serializers.py b/events/serializers.py
index dad6b6a..92f1827 100644
--- a/events/serializers.py
+++ b/events/serializers.py
@@ -1,11 +1,12 @@
 from rest_framework import serializers
 from drf_spectacular.utils import extend_schema_field
+from bugsink.api_serializers import UTCModelSerializer
 
 from .markdown_stacktrace import render_stacktrace_md
 from .models import Event
 
 
-class EventListSerializer(serializers.ModelSerializer):
+class EventListSerializer(UTCModelSerializer):
     """Lightweight list view: excludes the (potentially large) `data` field."""
 
     class Meta:
@@ -23,7 +24,7 @@ class EventListSerializer(serializers.ModelSerializer):
         ]
 
 
-class EventDetailSerializer(serializers.ModelSerializer):
+class EventDetailSerializer(UTCModelSerializer):
     """Detail view: includes full `data` payload."""
     # NOTE as with Issue.grouping_keys: check viewset for prefetching
     # grouping_key = serializers.CharField(source="grouping.grouping_key", read_only=True)
diff --git a/issues/serializers.py b/issues/serializers.py
index a8e482f..e07f67e 100644
--- a/issues/serializers.py
+++ b/issues/serializers.py
@@ -1,9 +1,9 @@
-from rest_framework import serializers
+from bugsink.api_serializers import UTCModelSerializer
 
 from .models import Issue
 
 
-class IssueSerializer(serializers.ModelSerializer):
+class IssueSerializer(UTCModelSerializer):
     # grouping_keys = serializers.SerializerMethodField()  # read-only list of strings
 
     class Meta:
diff --git a/projects/serializers.py b/projects/serializers.py
index df5d824..3621b8c 100644
--- a/projects/serializers.py
+++ b/projects/serializers.py
@@ -1,4 +1,5 @@
 from rest_framework import serializers
+from bugsink.api_serializers import UTCModelSerializer
 from bugsink.api_fields import make_enum_field
 
 from teams.models import Team
@@ -11,7 +12,7 @@ from .models import Project, ProjectVisibility
 ProjectVisibilityField = make_enum_field(ProjectVisibility)
 
 
-class ProjectListSerializer(serializers.ModelSerializer):
+class ProjectListSerializer(UTCModelSerializer):
     visibility = ProjectVisibilityField()
     dsn = serializers.CharField(read_only=True)
 
@@ -33,7 +34,7 @@ class ProjectListSerializer(serializers.ModelSerializer):
         ]
 
 
-class ProjectDetailSerializer(ExpandableSerializerMixin, serializers.ModelSerializer):
+class ProjectDetailSerializer(ExpandableSerializerMixin, UTCModelSerializer):
     expandable_fields = {"team": TeamDetailSerializer}
     visibility = ProjectVisibilityField()
     dsn = serializers.CharField(read_only=True)
@@ -56,7 +57,7 @@ class ProjectDetailSerializer(ExpandableSerializerMixin, serializers.ModelSerial
         ]
 
 
-class ProjectCreateUpdateSerializer(serializers.ModelSerializer):
+class ProjectCreateUpdateSerializer(UTCModelSerializer):
     id = serializers.UUIDField(read_only=True)
     team = serializers.PrimaryKeyRelatedField(queryset=Team.objects.all())
     visibility = ProjectVisibilityField(required=False)
diff --git a/releases/serializers.py b/releases/serializers.py
index 4b82227..6fb6065 100644
--- a/releases/serializers.py
+++ b/releases/serializers.py
@@ -1,5 +1,7 @@
+import datetime
 from django.utils import timezone
 from rest_framework import serializers
+from bugsink.api_serializers import UTCModelSerializer
 
 from projects.models import Project
 from rest_framework.exceptions import ValidationError
@@ -7,13 +9,13 @@ from rest_framework.exceptions import ValidationError
 from .models import Release, create_release_if_needed
 
 
-class ReleaseListSerializer(serializers.ModelSerializer):
+class ReleaseListSerializer(UTCModelSerializer):
     class Meta:
         model = Release
         fields = ["id", "project", "version", "date_released"]
 
 
-class ReleaseDetailSerializer(serializers.ModelSerializer):
+class ReleaseDetailSerializer(UTCModelSerializer):
     class Meta:
         model = Release
         fields = ["id", "project", "version", "date_released", "semver", "is_semver", "sort_epoch"]
@@ -23,7 +25,7 @@ class ReleaseDetailSerializer(serializers.ModelSerializer):
 class ReleaseCreateSerializer(serializers.Serializer):
     project = serializers.PrimaryKeyRelatedField(queryset=Project.objects.all())
     version = serializers.CharField(allow_blank=True)
-    timestamp = serializers.DateTimeField(required=False)
+    timestamp = serializers.DateTimeField(required=False, default_timezone=datetime.timezone.utc)
 
     def create(self, validated_data):
         project = validated_data["project"]
diff --git a/teams/serializers.py b/teams/serializers.py
index 7e15b38..2e617e0 100644
--- a/teams/serializers.py
+++ b/teams/serializers.py
@@ -1,12 +1,13 @@
 from rest_framework import serializers
 from bugsink.api_fields import make_enum_field
+from bugsink.api_serializers import UTCModelSerializer
 from .models import Team, TeamVisibility
 
 
 TeamVisibilityField = make_enum_field(TeamVisibility)
 
 
-class TeamListSerializer(serializers.ModelSerializer):
+class TeamListSerializer(UTCModelSerializer):
     visibility = TeamVisibilityField()
 
     class Meta:
@@ -14,7 +15,7 @@ class TeamListSerializer(serializers.ModelSerializer):
         fields = ["id", "name", "visibility"]
 
 
-class TeamDetailSerializer(serializers.ModelSerializer):
+class TeamDetailSerializer(UTCModelSerializer):
     visibility = TeamVisibilityField()
 
     class Meta:
@@ -22,7 +23,7 @@ class TeamDetailSerializer(serializers.ModelSerializer):
         fields = ["id", "name", "visibility"]
 
 
-class TeamCreateUpdateSerializer(serializers.ModelSerializer):
+class TeamCreateUpdateSerializer(UTCModelSerializer):
     id = serializers.UUIDField(read_only=True)
     visibility = TeamVisibilityField(required=False)