diff --git a/plotly/tests/test_core/test_utils/__init__.py b/plotly/tests/test_core/test_utils/__init__.py
new file mode 100644
index 00000000000..dbd5b79d852
--- /dev/null
+++ b/plotly/tests/test_core/test_utils/__init__.py
@@ -0,0 +1,3 @@
+def setup_package():
+    import warnings
+    warnings.filterwarnings('ignore')
diff --git a/plotly/tests/test_core/test_utils/test_utils.py b/plotly/tests/test_core/test_utils/test_utils.py
new file mode 100644
index 00000000000..5f0a62d88ed
--- /dev/null
+++ b/plotly/tests/test_core/test_utils/test_utils.py
@@ -0,0 +1,13 @@
+import json
+from unittest import TestCase
+
+from plotly.utils import PlotlyJSONEncoder
+
+
+class TestJSONEncoder(TestCase):
+
+    def test_nan_to_null(self):
+        array = [1, float('NaN'), float('Inf'), float('-Inf'), 'platypus']
+        result = json.dumps(array, cls=PlotlyJSONEncoder)
+        expected_result = '[1, null, null, null, "platypus"]'
+        self.assertEqual(result, expected_result)
diff --git a/plotly/tests/test_optional/test_utils/test_utils.py b/plotly/tests/test_optional/test_utils/test_utils.py
index dc54e2f1dbd..a1450913860 100644
--- a/plotly/tests/test_optional/test_utils/test_utils.py
+++ b/plotly/tests/test_optional/test_utils/test_utils.py
@@ -173,7 +173,7 @@ def test_column_json_encoding():
            '"2014-01-05 01:01:01", '
            '"2014-01-05 01:01:01.000001"], '
            '"name": "col 2"}, '
-           '{"data": [1, 2, 3, NaN, NaN, Infinity, '
+           '{"data": [1, 2, 3, null, null, null, '
            '"2014-01-05"], "name": "col 3"}]' == json_columns)
 
 
@@ -188,7 +188,7 @@ def test_figure_json_encoding():
     js2 = json.dumps(s2, cls=utils.PlotlyJSONEncoder, sort_keys=True)
 
     assert(js1 == '{"type": "scatter3d", "x": [1, 2, 3], '
-                  '"y": [1, 2, 3, NaN, NaN, Infinity, "2014-01-05"], '
+                  '"y": [1, 2, 3, null, null, null, "2014-01-05"], '
                   '"z": [1, "A", "2014-01-05", '
                   '"2014-01-05 01:01:01", "2014-01-05 01:01:01.000001"]}')
     assert(js2 == '{"type": "scatter", "x": [1, 2, 3]}')
@@ -219,7 +219,7 @@ def test_datetime_json_encoding():
 
 def test_pandas_json_encoding():
     j1 = json.dumps(df['col 1'], cls=utils.PlotlyJSONEncoder)
-    assert(j1 == '[1, 2, 3, "2014-01-05", null, NaN, Infinity]')
+    assert(j1 == '[1, 2, 3, "2014-01-05", null, null, null]')
 
     # Test that data wasn't mutated
     assert_series_equal(df['col 1'],
@@ -249,7 +249,7 @@ def test_numpy_masked_json_encoding():
     l = [1, 2, np.ma.core.masked]
     j1 = json.dumps(l, cls=utils.PlotlyJSONEncoder)
     print j1
-    assert(j1 == '[1, 2, NaN]')
+    assert(j1 == '[1, 2, null]')
     assert(set(l) == set([1, 2, np.ma.core.masked]))
 
 
@@ -276,7 +276,7 @@ def test_masked_constants_example():
     jy = json.dumps(renderer.plotly_fig['data'][1]['y'],
                     cls=utils.PlotlyJSONEncoder)
     assert(jy == '[-398.11793026999999, -398.11792966000002, '
-                 '-398.11786308000001, NaN]')
+                 '-398.11786308000001, null]')
 
 
 def test_numpy_dates():
diff --git a/plotly/utils.py b/plotly/utils.py
index 216f0077b20..e948a07507f 100644
--- a/plotly/utils.py
+++ b/plotly/utils.py
@@ -119,8 +119,72 @@ class PlotlyJSONEncoder(json.JSONEncoder):
 
     See PlotlyJSONEncoder.default for more implementation information.
 
+    Additionally, this encoder overrides nan functionality so that 'Inf',
+    'NaN' and '-Inf' encode to 'null'. Which is stricter JSON than the Python
+    version.
+
     """
 
+    # we want stricter JSON, so convert NaN, Inf, -Inf --> 'null'
+    nan_str = inf_str = neg_inf_str = 'null'
+
+    # uses code from official python json.encoder module. Same licence applies.
+    def iterencode(self, o, _one_shot=False):
+        """
+        Encode the given object and yield each string
+        representation as available.
+
+        For example::
+
+            for chunk in JSONEncoder().iterencode(bigobject):
+                mysocket.write(chunk)
+
+        """
+        if self.check_circular:
+            markers = {}
+        else:
+            markers = None
+        if self.ensure_ascii:
+            _encoder = json.encoder.encode_basestring_ascii
+        else:
+            _encoder = json.encoder.encode_basestring
+        if self.encoding != 'utf-8':
+            def _encoder(o, _orig_encoder=_encoder, _encoding=self.encoding):
+                if isinstance(o, str):
+                    o = o.decode(_encoding)
+                return _orig_encoder(o)
+
+        def floatstr(o, allow_nan=self.allow_nan,
+                     _repr=json.encoder.FLOAT_REPR, _inf=json.encoder.INFINITY,
+                     _neginf=-json.encoder.INFINITY):
+            # Check for specials.  Note that this type of test is processor
+            # and/or platform-specific, so do tests which don't depend on the
+            # internals.
+
+            # *any* two NaNs are not equivalent (even to itself) try:
+            # float('NaN') == float('NaN')
+            if o != o:
+                text = self.nan_str
+            elif o == _inf:
+                text = self.inf_str
+            elif o == _neginf:
+                text = self.neg_inf_str
+            else:
+                return _repr(o)
+
+            if not allow_nan:
+                raise ValueError(
+                    "Out of range float values are not JSON compliant: " +
+                    repr(o))
+
+            return text
+
+        _iterencode = json.encoder._make_iterencode(
+                markers, self.default, _encoder, self.indent, floatstr,
+                self.key_separator, self.item_separator, self.sort_keys,
+                self.skipkeys, _one_shot)
+        return _iterencode(o, 0)
+
     def default(self, obj):
         """
         Accept an object (of unknown type) and try to encode with priority:
diff --git a/plotly/version.py b/plotly/version.py
index 970bb6f45e7..9a5e84e0a7a 100644
--- a/plotly/version.py
+++ b/plotly/version.py
@@ -1 +1 @@
-__version__ = '1.6.10'
+__version__ = '1.6.11'