diff --git a/moulinette/interfaces/__init__.py b/moulinette/interfaces/__init__.py
index dc33e276..a5d32cac 100644
--- a/moulinette/interfaces/__init__.py
+++ b/moulinette/interfaces/__init__.py
@@ -4,7 +4,9 @@ import re
 import logging
 import argparse
 import copy
+import datetime
 from collections import deque, OrderedDict
+from json.encoder import JSONEncoder
 
 from moulinette import m18n
 from moulinette.core import MoulinetteError
@@ -560,3 +562,40 @@ class PositionalsFirstHelpFormatter(argparse.HelpFormatter):
 
         # prefix with 'usage:'
         return "%s%s\n\n" % (prefix, usage)
+
+
+class JSONExtendedEncoder(JSONEncoder):
+
+    """Extended JSON encoder
+
+    Extend default JSON encoder to recognize more types and classes. It will
+    never raise an exception if the object can't be encoded and return its repr
+    instead.
+
+    The following objects and types are supported:
+        - set: converted into list
+
+    """
+
+    def default(self, o):
+
+        import pytz  # Lazy loading, this takes like 3+ sec on a RPi2 ?!
+
+        """Return a serializable object"""
+        # Convert compatible containers into list
+        if isinstance(o, set) or (hasattr(o, "__iter__") and hasattr(o, "next")):
+            return list(o)
+
+        # Display the date in its iso format ISO-8601 Internet Profile (RFC 3339)
+        if isinstance(o, datetime.date):
+            if o.tzinfo is None:
+                o = o.replace(tzinfo=pytz.utc)
+            return o.isoformat()
+
+        # Return the repr for object that json can't encode
+        logger.warning(
+            "cannot properly encode in JSON the object %s, " "returned repr is: %r",
+            type(o),
+            o,
+        )
+        return repr(o)
diff --git a/moulinette/interfaces/api.py b/moulinette/interfaces/api.py
index 3e05e57f..c7b929c1 100644
--- a/moulinette/interfaces/api.py
+++ b/moulinette/interfaces/api.py
@@ -21,9 +21,9 @@ from moulinette.core import MoulinetteError, MoulinetteValidationError
 from moulinette.interfaces import (
     BaseActionsMapParser,
     ExtendedArgumentParser,
+    JSONExtendedEncoder,
 )
 from moulinette.utils import log
-from moulinette.utils.serialize import JSONExtendedEncoder
 from moulinette.utils.text import random_ascii
 
 logger = log.getLogger("moulinette.interface.api")
diff --git a/moulinette/interfaces/cli.py b/moulinette/interfaces/cli.py
index 733f6301..7d64a1e6 100644
--- a/moulinette/interfaces/cli.py
+++ b/moulinette/interfaces/cli.py
@@ -5,7 +5,7 @@ import sys
 import getpass
 import locale
 import logging
-from argparse import SUPPRESS
+import argparse
 from collections import OrderedDict
 from datetime import date, datetime
 
@@ -17,6 +17,7 @@ from moulinette.core import MoulinetteError, MoulinetteValidationError
 from moulinette.interfaces import (
     BaseActionsMapParser,
     ExtendedArgumentParser,
+    JSONExtendedEncoder,
 )
 from moulinette.utils import log
 
@@ -32,17 +33,14 @@ from moulinette.utils import log
 # But it display instead:
 #       Error: unable to parse arguments 'firewall' because: sequence item 0: expected str instance, NoneType found
 
-import argparse
-
-
 def monkey_get_action_name(argument):
     if argument is None:
         return None
     elif argument.option_strings:
         return "/".join(argument.option_strings)
-    elif argument.metavar not in (None, SUPPRESS):
+    elif argument.metavar not in (None, argparse.SUPPRESS):
         return argument.metavar
-    elif argument.dest not in (None, SUPPRESS):
+    elif argument.dest not in (None, argparse.SUPPRESS):
         return argument.dest
     elif argument.choices:
         return "{" + ",".join(argument.choices) + "}"
@@ -307,7 +305,7 @@ class ActionsMapParser(BaseActionsMapParser):
 
             # Append each top parser action to the global group
             for action in top_parser._actions:
-                action.dest = SUPPRESS
+                action.dest = argparse.SUPPRESS
                 self.global_parser._add_action(action)
 
     # Implement virtual properties
@@ -509,8 +507,6 @@ class Interface:
         if output_as:
             if output_as == "json":
                 import json
-                from moulinette.utils.serialize import JSONExtendedEncoder
-
                 print(json.dumps(ret, cls=JSONExtendedEncoder))
             else:
                 plain_print_dict(ret)
diff --git a/moulinette/utils/serialize.py b/moulinette/utils/serialize.py
deleted file mode 100644
index 345cb4d4..00000000
--- a/moulinette/utils/serialize.py
+++ /dev/null
@@ -1,45 +0,0 @@
-import logging
-from json.encoder import JSONEncoder
-import datetime
-
-logger = logging.getLogger("moulinette.utils.serialize")
-
-
-# JSON utilities -------------------------------------------------------
-
-
-class JSONExtendedEncoder(JSONEncoder):
-
-    """Extended JSON encoder
-
-    Extend default JSON encoder to recognize more types and classes. It will
-    never raise an exception if the object can't be encoded and return its repr
-    instead.
-
-    The following objects and types are supported:
-        - set: converted into list
-
-    """
-
-    def default(self, o):
-
-        import pytz  # Lazy loading, this takes like 3+ sec on a RPi2 ?!
-
-        """Return a serializable object"""
-        # Convert compatible containers into list
-        if isinstance(o, set) or (hasattr(o, "__iter__") and hasattr(o, "next")):
-            return list(o)
-
-        # Display the date in its iso format ISO-8601 Internet Profile (RFC 3339)
-        if isinstance(o, datetime.date):
-            if o.tzinfo is None:
-                o = o.replace(tzinfo=pytz.utc)
-            return o.isoformat()
-
-        # Return the repr for object that json can't encode
-        logger.warning(
-            "cannot properly encode in JSON the object %s, " "returned repr is: %r",
-            type(o),
-            o,
-        )
-        return repr(o)
diff --git a/test/test_serialize.py b/test/test_serialize.py
index a87bfa9b..bf4b2342 100644
--- a/test/test_serialize.py
+++ b/test/test_serialize.py
@@ -1,5 +1,5 @@
 from datetime import datetime as dt
-from moulinette.utils.serialize import JSONExtendedEncoder
+from moulinette.interface import JSONExtendedEncoder
 
 
 def test_json_extended_encoder(caplog):