diff --git a/labthings/server/default_views/tasks.py b/labthings/server/default_views/tasks.py
index 4515d89a..09bdb4fa 100644
--- a/labthings/server/default_views/tasks.py
+++ b/labthings/server/default_views/tasks.py
@@ -1,4 +1,4 @@
-from flask import abort, url_for
+from flask import abort
 
 from ..decorators import marshal_with, Tag
 from ..view import View
diff --git a/labthings/server/types/annotations.py b/labthings/server/types/annotations.py
index ceb1966c..2d7ec12e 100644
--- a/labthings/server/types/annotations.py
+++ b/labthings/server/types/annotations.py
@@ -1,7 +1,7 @@
 from .registry import TypeRegistry
 from labthings.server import fields
 
-from typing import Dict, List, Tuple, Union
+from typing import List, Tuple
 from inspect import Parameter
 from marshmallow.base import FieldABC
 
diff --git a/labthings/server/types/preprocess.py b/labthings/server/types/preprocess.py
index 3dcf3adf..65fc313e 100644
--- a/labthings/server/types/preprocess.py
+++ b/labthings/server/types/preprocess.py
@@ -1,5 +1,4 @@
 # Functions to handle conversion of common Python types into serialisable Python types
-from apispec.ext.marshmallow.field_converter import DEFAULT_FIELD_MAPPING
 import inspect
 
 from .registry import TypeRegistry
diff --git a/labthings/server/types/properties.py b/labthings/server/types/properties.py
index cbc8a72f..e9924194 100644
--- a/labthings/server/types/properties.py
+++ b/labthings/server/types/properties.py
@@ -5,7 +5,7 @@
 from labthings.core.utilities import rapply
 
 from marshmallow.base import FieldABC
-from typing import Dict, List, Tuple, Union
+from typing import List, Tuple, Union
 import copy
 
 
diff --git a/labthings/server/types/registry.py b/labthings/server/types/registry.py
index f6d454a1..88ac248d 100644
--- a/labthings/server/types/registry.py
+++ b/labthings/server/types/registry.py
@@ -3,7 +3,7 @@
 from marshmallow.base import FieldABC
 from datetime import date, datetime, time, timedelta
 from decimal import Decimal
-from typing import Dict, List, Tuple, Union
+from typing import Dict, Tuple
 from uuid import UUID
 from inspect import _empty