diff --git a/netbox/circuits/api/serializers.py b/netbox/circuits/api/serializers.py
index 4703458a6..b36d22105 100644
--- a/netbox/circuits/api/serializers.py
+++ b/netbox/circuits/api/serializers.py
@@ -28,11 +28,14 @@ class NestedProviderSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'name', 'slug']
 
 
-class WritableProviderSerializer(serializers.ModelSerializer):
+class WritableProviderSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Provider
-        fields = ['id', 'name', 'slug', 'asn', 'account', 'portal_url', 'noc_contact', 'admin_contact', 'comments']
+        fields = [
+            'id', 'name', 'slug', 'asn', 'account', 'portal_url', 'noc_contact', 'admin_contact', 'comments',
+            'custom_fields',
+        ]
 
 
 #
@@ -79,11 +82,14 @@ class NestedCircuitSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'cid']
 
 
-class WritableCircuitSerializer(serializers.ModelSerializer):
+class WritableCircuitSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Circuit
-        fields = ['id', 'cid', 'provider', 'type', 'tenant', 'install_date', 'commit_rate', 'description', 'comments']
+        fields = [
+            'id', 'cid', 'provider', 'type', 'tenant', 'install_date', 'commit_rate', 'description', 'comments',
+            'custom_fields',
+        ]
 
 
 #
diff --git a/netbox/dcim/api/serializers.py b/netbox/dcim/api/serializers.py
index de93f836b..a9c52e3fd 100644
--- a/netbox/dcim/api/serializers.py
+++ b/netbox/dcim/api/serializers.py
@@ -150,13 +150,13 @@ class NestedRackSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'name', 'display_name']
 
 
-class WritableRackSerializer(serializers.ModelSerializer):
+class WritableRackSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Rack
         fields = [
             'id', 'name', 'facility_id', 'site', 'group', 'tenant', 'role', 'type', 'width', 'u_height', 'desc_units',
-            'comments',
+            'comments', 'custom_fields',
         ]
         # Omit the UniqueTogetherValidator that would be automatically added to validate (site, facility_id). This
         # prevents facility_id from being interpreted as a required field.
@@ -263,13 +263,13 @@ class NestedDeviceTypeSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'manufacturer', 'model', 'slug']
 
 
-class WritableDeviceTypeSerializer(serializers.ModelSerializer):
+class WritableDeviceTypeSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = DeviceType
         fields = [
             'id', 'manufacturer', 'model', 'slug', 'part_number', 'u_height', 'is_full_depth', 'interface_ordering',
-            'is_console_server', 'is_pdu', 'is_network_device', 'subdevice_role', 'comments',
+            'is_console_server', 'is_pdu', 'is_network_device', 'subdevice_role', 'comments', 'custom_fields',
         ]
 
 
@@ -476,13 +476,13 @@ class DeviceSerializer(CustomFieldModelSerializer):
         }
 
 
-class WritableDeviceSerializer(serializers.ModelSerializer):
+class WritableDeviceSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Device
         fields = [
             'id', 'name', 'device_type', 'device_role', 'tenant', 'platform', 'serial', 'asset_tag', 'site', 'rack',
-            'position', 'face', 'status', 'primary_ip4', 'primary_ip6', 'comments',
+            'position', 'face', 'status', 'primary_ip4', 'primary_ip6', 'comments', 'custom_fields',
         ]
         validators = []
 
diff --git a/netbox/ipam/api/serializers.py b/netbox/ipam/api/serializers.py
index 5a350acb7..7d9a5778c 100644
--- a/netbox/ipam/api/serializers.py
+++ b/netbox/ipam/api/serializers.py
@@ -31,11 +31,11 @@ class NestedVRFSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'name', 'rd']
 
 
-class WritableVRFSerializer(serializers.ModelSerializer):
+class WritableVRFSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = VRF
-        fields = ['id', 'name', 'rd', 'tenant', 'enforce_unique', 'description']
+        fields = ['id', 'name', 'rd', 'tenant', 'enforce_unique', 'description', 'custom_fields']
 
 
 #
@@ -96,11 +96,11 @@ class NestedAggregateSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'family', 'prefix']
 
 
-class WritableAggregateSerializer(serializers.ModelSerializer):
+class WritableAggregateSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Aggregate
-        fields = ['id', 'prefix', 'rir', 'date_added', 'description']
+        fields = ['id', 'prefix', 'rir', 'date_added', 'description', 'custom_fields']
 
 
 #
@@ -169,11 +169,11 @@ class NestedVLANSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'vid', 'name', 'display_name']
 
 
-class WritableVLANSerializer(serializers.ModelSerializer):
+class WritableVLANSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = VLAN
-        fields = ['id', 'site', 'group', 'vid', 'name', 'tenant', 'status', 'role', 'description']
+        fields = ['id', 'site', 'group', 'vid', 'name', 'tenant', 'status', 'role', 'description', 'custom_fields']
         validators = []
 
     def validate(self, data):
@@ -216,11 +216,14 @@ class NestedPrefixSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'family', 'prefix']
 
 
-class WritablePrefixSerializer(serializers.ModelSerializer):
+class WritablePrefixSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Prefix
-        fields = ['id', 'prefix', 'site', 'vrf', 'tenant', 'vlan', 'status', 'role', 'is_pool', 'description']
+        fields = [
+            'id', 'prefix', 'site', 'vrf', 'tenant', 'vlan', 'status', 'role', 'is_pool', 'description',
+            'custom_fields',
+        ]
 
 
 #
@@ -252,11 +255,11 @@ IPAddressSerializer._declared_fields['nat_inside'] = NestedIPAddressSerializer()
 IPAddressSerializer._declared_fields['nat_outside'] = NestedIPAddressSerializer()
 
 
-class WritableIPAddressSerializer(serializers.ModelSerializer):
+class WritableIPAddressSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = IPAddress
-        fields = ['id', 'address', 'vrf', 'tenant', 'status', 'interface', 'description', 'nat_inside']
+        fields = ['id', 'address', 'vrf', 'tenant', 'status', 'interface', 'description', 'nat_inside', 'custom_fields']
 
 
 #
diff --git a/netbox/tenancy/api/serializers.py b/netbox/tenancy/api/serializers.py
index 67231fe67..e649b6f03 100644
--- a/netbox/tenancy/api/serializers.py
+++ b/netbox/tenancy/api/serializers.py
@@ -43,8 +43,8 @@ class NestedTenantSerializer(serializers.ModelSerializer):
         fields = ['id', 'url', 'name', 'slug']
 
 
-class WritableTenantSerializer(serializers.ModelSerializer):
+class WritableTenantSerializer(CustomFieldModelSerializer):
 
     class Meta:
         model = Tenant
-        fields = ['id', 'name', 'slug', 'group', 'description', 'comments']
+        fields = ['id', 'name', 'slug', 'group', 'description', 'comments', 'custom_fields']