diff --git a/README.rst b/README.rst
index fbae79f..dd56e13 100644
--- a/README.rst
+++ b/README.rst
@@ -60,8 +60,7 @@ Main features
 -   Framework independence : adapters are provided to easily integrate
     your API in any web framework, for example a wsgi container,
     Pecan_, Flask_, ...
--   Very few runtime dependencies: webob, simplegeneric. Optionally
-    simplejson if you need better performances.
+-   Very few runtime dependencies: webob, simplegeneric.
 -   Integration in `Sphinx`_ for making clean documentation with
     ``wsmeext.sphinxext``.
 
diff --git a/tox.ini b/tox.ini
index c3eb013..f4c4452 100644
--- a/tox.ini
+++ b/tox.ini
@@ -87,16 +87,6 @@ deps =
   {[common]basedeps}
 basepython = python2.7
 
-[testenv:py27-simplejson]
-commands =
-  {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
-  {envbindir}/coverage report --show-missing wsme/*.py wsme/rest/*.py wsmeext/*.py
-deps =
-  {[common]testtools}
-  {[common]basedeps}
-  simplejson
-basepython = python2.7
-
 [testenv:py35]
 commands =
   {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
@@ -106,16 +96,6 @@ deps =
   {[common]basedeps}
 basepython = python3.5
 
-[testenv:py35-simplejson]
-commands =
-  {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
-  {envbindir}/coverage report --show-missing wsme/*.py wsme/rest/*.py wsmeext/*.py
-deps =
-  {[common]testtools}
-  {[common]basedeps}
-  simplejson
-basepython = python3.5
-
 [testenv:py36]
 commands =
   {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
@@ -125,16 +105,6 @@ deps =
   {[common]basedeps}
 basepython = python3.6
 
-[testenv:py36-simplejson]
-commands =
-  {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
-  {envbindir}/coverage report --show-missing wsme/*.py wsme/rest/*.py wsmeext/*.py
-deps =
-  {[common]testtools}
-  {[common]basedeps}
-  simplejson
-basepython = python3.6
-
 [testenv:pypy]
 commands =
   {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
@@ -142,12 +112,3 @@ commands =
 deps =
   {[common]testtools}
   {[common]basedeps}
-
-[testenv:pypy-simplejson]
-commands =
-  {envbindir}/coverage run {envbindir}/nosetests --nologcapture --with-xunit --xunit-file nosetests-{envname}.xml wsme/tests tests/pecantest tests/test_sphinxext.py tests/test_flask.py --verbose {posargs}
-  {envbindir}/coverage report --show-missing wsme/*.py wsme/rest/*.py wsmeext/*.py
-deps =
-  {[common]testtools}
-  {[common]basedeps}
-  simplejson
diff --git a/wsme/rest/args.py b/wsme/rest/args.py
index 9dc16c7..2a49672 100644
--- a/wsme/rest/args.py
+++ b/wsme/rest/args.py
@@ -216,8 +216,8 @@ def args_from_params(funcdef, params):
 
 
 def args_from_body(funcdef, body, mimetype):
-    from wsme.rest import json as restjson
-    from wsme.rest import xml as restxml
+    from wsme.rest import json_utils as restjson
+    from wsme.rest import xml_utils as restxml
 
     if funcdef.body_type is not None:
         datatypes = {funcdef.arguments[-1].name: funcdef.body_type}
diff --git a/wsme/rest/json.py b/wsme/rest/json_utils.py
similarity index 98%
rename from wsme/rest/json.py
rename to wsme/rest/json_utils.py
index 48bd082..a7c2f4f 100644
--- a/wsme/rest/json.py
+++ b/wsme/rest/json_utils.py
@@ -1,11 +1,10 @@
 """REST+Json protocol implementation."""
-from __future__ import absolute_import
 import datetime
 import decimal
-
-import six
+import json
 
 from simplegeneric import generic
+import six
 
 import wsme.exc
 import wsme.types
@@ -13,12 +12,6 @@ from wsme.types import Unset
 import wsme.utils
 
 
-try:
-    import simplejson as json
-except ImportError:
-    import json  # noqa
-
-
 content_type = 'application/json'
 accept_content_types = [
     content_type,
diff --git a/wsme/rest/protocol.py b/wsme/rest/protocol.py
index 5201ccf..7748635 100644
--- a/wsme/rest/protocol.py
+++ b/wsme/rest/protocol.py
@@ -25,8 +25,8 @@ class RestProtocol(Protocol):
         self.content_types = []
 
         for dataformat in dataformats:
-            __import__('wsme.rest.' + dataformat)
-            dfmod = getattr(wsme.rest, dataformat)
+            __import__('wsme.rest.' + dataformat + '_utils')
+            dfmod = getattr(wsme.rest, dataformat + '_utils')
             self.dataformats[dataformat] = dfmod
             self.content_types.extend(dfmod.accept_content_types)
 
diff --git a/wsme/rest/xml.py b/wsme/rest/xml_utils.py
similarity index 100%
rename from wsme/rest/xml.py
rename to wsme/rest/xml_utils.py
diff --git a/wsme/tests/test_api.py b/wsme/tests/test_api.py
index fc1e157..f371340 100644
--- a/wsme/tests/test_api.py
+++ b/wsme/tests/test_api.py
@@ -80,8 +80,8 @@ class TestController(unittest.TestCase):
                             headers={'Accept': 'application/json'})
         self.assertTrue(
             res.json_body['faultstring'].startswith(
-                "Invalid input for field/attribute number. Value: 'arf'. \
-Value should be one of:"))
+                "Invalid input for field/attribute number. Value: 'arf'. "
+                "Value should be one of:"))
         self.assertIn('v1', res.json_body['faultstring'])
         self.assertIn('v2', res.json_body['faultstring'])
         self.assertIn('None', res.json_body['faultstring'])
@@ -104,8 +104,8 @@ Value should be one of:"))
                             headers={'Accept': 'application/json'})
         self.assertTrue(
             res.json_body['faultstring'].startswith(
-                "Invalid input for field/attribute number. Value: '1'. \
-Value should be one of:"))
+                "Invalid input for field/attribute number. Value: '1'. "
+                "Value should be one of:"))
         self.assertIn('v1', res.json_body['faultstring'])
         self.assertIn('v2', res.json_body['faultstring'])
         self.assertIn('None', res.json_body['faultstring'])
diff --git a/wsme/tests/test_restjson.py b/wsme/tests/test_restjson.py
index 7afbb86..eca8e47 100644
--- a/wsme/tests/test_restjson.py
+++ b/wsme/tests/test_restjson.py
@@ -1,21 +1,15 @@
 import base64
 import datetime
 import decimal
+import json
 
-import wsme.tests.protocol
-
-try:
-    import simplejson as json
-except ImportError:
-    import json  # noqa
-
-from wsme.rest.json import fromjson, tojson, parse
-from wsme.utils import parse_isodatetime, parse_isotime, parse_isodate
+from wsme.exc import ClientSideError, InvalidInput
 from wsme.types import isarray, isdict, isusertype, register_type
 from wsme.types import UserType, ArrayType, DictType
 from wsme.rest import expose, validate
-from wsme.exc import ClientSideError, InvalidInput
-
+from wsme.rest.json_utils import fromjson, tojson, parse
+import wsme.tests.protocol
+from wsme.utils import parse_isodatetime, parse_isotime, parse_isodate
 
 import six
 from six import b, u
@@ -569,7 +563,7 @@ class TestRestJson(wsme.tests.protocol.RestOnlyProtocolTestCase):
         v.aint = 4
         v.astr = 's'
 
-        r = wsme.rest.json.encode_sample_value(MyType, v, True)
+        r = wsme.rest.json_utils.encode_sample_value(MyType, v, True)
         print(r)
         assert r[0] == ('javascript')
         assert r[1] == json.dumps({'aint': 4, 'astr': 's'}, ensure_ascii=False,
@@ -580,7 +574,7 @@ class TestRestJson(wsme.tests.protocol.RestOnlyProtocolTestCase):
         assert tojson(wsme.types.bytes, b('ascii')) == u('ascii')
 
     def test_encode_sample_params(self):
-        r = wsme.rest.json.encode_sample_params(
+        r = wsme.rest.json_utils.encode_sample_params(
             [('a', int, 2)], True
         )
         assert r[0] == 'javascript', r[0]
@@ -589,7 +583,7 @@ class TestRestJson(wsme.tests.protocol.RestOnlyProtocolTestCase):
 }''', r[1]
 
     def test_encode_sample_result(self):
-        r = wsme.rest.json.encode_sample_result(
+        r = wsme.rest.json_utils.encode_sample_result(
             int, 2, True
         )
         assert r[0] == 'javascript', r[0]
diff --git a/wsme/tests/test_restxml.py b/wsme/tests/test_restxml.py
index b677a65..3fc01fe 100644
--- a/wsme/tests/test_restxml.py
+++ b/wsme/tests/test_restxml.py
@@ -5,11 +5,10 @@ import base64
 from six import u, b
 import six
 
+from wsme.rest.xml_utils import fromxml, toxml
 import wsme.tests.protocol
-from wsme.utils import parse_isodatetime, parse_isodate, parse_isotime
 from wsme.types import isarray, isdict, isusertype, register_type
-
-from wsme.rest.xml import fromxml, toxml
+from wsme.utils import parse_isodatetime, parse_isodate, parse_isotime
 
 try:
     import xml.etree.ElementTree as et
@@ -165,7 +164,7 @@ class TestRestXML(wsme.tests.protocol.RestOnlyProtocolTestCase):
         value.aint = 5
         value.atext = u('test')
 
-        language, sample = wsme.rest.xml.encode_sample_value(
+        language, sample = wsme.rest.xml_utils.encode_sample_value(
             MyType, value, True)
         print(language, sample)
 
@@ -176,13 +175,13 @@ class TestRestXML(wsme.tests.protocol.RestOnlyProtocolTestCase):
 </value>""")
 
     def test_encode_sample_params(self):
-        lang, content = wsme.rest.xml.encode_sample_params(
+        lang, content = wsme.rest.xml_utils.encode_sample_params(
             [('a', int, 2)], True)
         assert lang == 'xml', lang
         assert content == b('<parameters>\n  <a>2</a>\n</parameters>'), content
 
     def test_encode_sample_result(self):
-        lang, content = wsme.rest.xml.encode_sample_result(int, 2, True)
+        lang, content = wsme.rest.xml_utils.encode_sample_result(int, 2, True)
         assert lang == 'xml', lang
         assert content == b('<result>2</result>'), content
 
diff --git a/wsmeext/flask.py b/wsmeext/flask.py
index 4d9e446..d6e57ab 100644
--- a/wsmeext/flask.py
+++ b/wsmeext/flask.py
@@ -5,22 +5,22 @@ import logging
 import sys
 import inspect
 
+import flask
+
 import wsme
 import wsme.api
-import wsme.rest.json
-import wsme.rest.xml
 import wsme.rest.args
+import wsme.rest.json_utils
+import wsme.rest.xml_utils
 from wsme.utils import is_valid_code
 
-import flask
-
 log = logging.getLogger(__name__)
 
 
 TYPES = {
-    'application/json': wsme.rest.json,
-    'application/xml': wsme.rest.xml,
-    'text/xml': wsme.rest.xml
+    'application/json': wsme.rest.json_utils,
+    'application/xml': wsme.rest.xml_utils,
+    'text/xml': wsme.rest.xml_utils,
 }
 
 
@@ -35,9 +35,9 @@ def get_dataformat():
     if req_dataformat in TYPES:
         return TYPES[req_dataformat]
 
-    log.info('''Could not determine what format is wanted by the
-             caller, falling back to json''')
-    return wsme.rest.json
+    log.info('Could not determine what format is wanted by the caller, '
+             'falling back to JSON')
+    return wsme.rest.json_utils
 
 
 def signature(*args, **kw):
diff --git a/wsmeext/pecan.py b/wsmeext/pecan.py
index 9d63dde..474c45e 100644
--- a/wsmeext/pecan.py
+++ b/wsmeext/pecan.py
@@ -4,13 +4,12 @@ import functools
 import inspect
 import sys
 
-import wsme
-import wsme.rest.args
-import wsme.rest.json
-import wsme.rest.xml
-
 import pecan
 
+import wsme
+import wsme.rest.args
+import wsme.rest.json_utils
+import wsme.rest.xml_utils
 from wsme.utils import is_valid_code
 
 
@@ -22,8 +21,8 @@ class JSonRenderer(object):
     @staticmethod
     def render(template_path, namespace):
         if 'faultcode' in namespace:
-            return wsme.rest.json.encode_error(None, namespace)
-        return wsme.rest.json.encode_result(
+            return wsme.rest.json_utils.encode_error(None, namespace)
+        return wsme.rest.json_utils.encode_result(
             namespace['result'],
             namespace['datatype']
         )
@@ -37,8 +36,8 @@ class XMLRenderer(object):
     @staticmethod
     def render(template_path, namespace):
         if 'faultcode' in namespace:
-            return wsme.rest.xml.encode_error(None, namespace)
-        return wsme.rest.xml.encode_result(
+            return wsme.rest.xml_utils.encode_error(None, namespace)
+        return wsme.rest.xml_utils.encode_result(
             namespace['result'],
             namespace['datatype']
         )
diff --git a/wsmeext/sphinxext.py b/wsmeext/sphinxext.py
index 7c45a0f..4ca5370 100644
--- a/wsmeext/sphinxext.py
+++ b/wsmeext/sphinxext.py
@@ -2,26 +2,23 @@ import inspect
 import re
 import sys
 
+from docutils.parsers.rst import Directive
+from docutils.parsers.rst import directives
 import six
-
 from sphinx import addnodes
 from sphinx.ext import autodoc
 from sphinx.domains.python import PyClasslike, PyClassmember
 from sphinx.domains import Domain, ObjType
 from sphinx.directives import ObjectDescription
+from sphinx.locale import l_, _
+from sphinx.roles import XRefRole
 from sphinx.util.docfields import Field
 from sphinx.util.nodes import make_refnode
 
-from sphinx.roles import XRefRole
-from sphinx.locale import l_, _
-
-from docutils.parsers.rst import Directive
-from docutils.parsers.rst import directives
-
 import wsme
+import wsme.rest.json_utils
+import wsme.rest.xml_utils
 import wsme.types
-import wsme.rest.json
-import wsme.rest.xml
 
 field_re = re.compile(r':(?P<field>\w+)(\s+(?P<name>\w+))?:')
 
@@ -56,10 +53,10 @@ def get_protocols(names):
         protocols.extend('restjson', 'restxml')
     if 'restjson' in names:
         names.remove('restjson')
-        protocols.append(('Json', wsme.rest.json))
+        protocols.append(('Json', wsme.rest.json_utils))
     if 'restxml' in names:
         names.remove('restxml')
-        protocols.append(('XML', wsme.rest.xml))
+        protocols.append(('XML', wsme.rest.xml_utils))
     for name in names:
         p = wsme.protocol.getprotocol(name)
         protocols.append((p.displayname or p.name, p))