diff --git a/rhodecode/lib/compat.py b/rhodecode/lib/compat.py
--- a/rhodecode/lib/compat.py
+++ b/rhodecode/lib/compat.py
@@ -25,16 +25,93 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import os
+import datetime
+import functools
+import decimal
 from rhodecode import __platform__, PLATFORM_WIN
 
 #==============================================================================
 # json
 #==============================================================================
+
+
+def _is_aware(value):
+    """
+    Determines if a given datetime.time is aware.
+
+    The logic is described in Python's docs:
+    http://docs.python.org/library/datetime.html#datetime.tzinfo
+    """
+    return (value.tzinfo is not None
+            and value.tzinfo.utcoffset(value) is not None)
+
+
+def _obj_dump(obj):
+    """
+    Custom function for dumping objects to JSON, if obj has __json__ attribute
+    or method defined it will be used for serialization
+
+    :param obj:
+    """
+
+    if isinstance(obj, complex):
+        return [obj.real, obj.imag]
+    # See "Date Time String Format" in the ECMA-262 specification.
+    # some code borrowed from django 1.4
+    elif isinstance(obj, datetime.datetime):
+        r = obj.isoformat()
+        if obj.microsecond:
+            r = r[:23] + r[26:]
+        if r.endswith('+00:00'):
+            r = r[:-6] + 'Z'
+        return r
+    elif isinstance(obj, datetime.date):
+        return obj.isoformat()
+    elif isinstance(obj, decimal.Decimal):
+        return str(obj)
+    elif isinstance(obj, datetime.time):
+        if _is_aware(obj):
+            raise ValueError("JSON can't represent timezone-aware times.")
+        r = obj.isoformat()
+        if obj.microsecond:
+            r = r[:12]
+        return r
+    elif isinstance(obj, set):
+        return list(obj)
+    elif isinstance(obj, OrderedDict):
+        return obj.as_dict()
+    elif hasattr(obj, '__json__'):
+        if callable(obj.__json__):
+            return obj.__json__()
+        else:
+            return obj.__json__
+    else:
+        raise NotImplementedError
+
 try:
     import json
+
+    # extended JSON encoder for json
+    class ExtendedEncoder(json.JSONEncoder):
+        def default(self, obj):
+            try:
+                return _obj_dump(obj)
+            except NotImplementedError:
+                pass
+            return json.JSONEncoder.default(self, obj)
+    # monkey-patch JSON encoder to use extended version
+    json.dumps = functools.partial(json.dumps, cls=ExtendedEncoder)
 except ImportError:
     import simplejson as json
 
+    def extended_encode(obj):
+        try:
+            return _obj_dump(obj)
+        except NotImplementedError:
+            pass
+        raise TypeError("%r is not JSON serializable" % (obj,))
+    json.dumps = functools.partial(json.dumps, default=extended_encode)
+
 
 #==============================================================================
 # izip_longest
@@ -44,11 +121,11 @@ try:
 except ImportError:
     import itertools
 
-    def izip_longest(*args, **kwds): # noqa
+    def izip_longest(*args, **kwds):
         fillvalue = kwds.get("fillvalue")
 
         def sentinel(counter=([fillvalue] * (len(args) - 1)).pop):
-            yield counter() # yields the fillvalue, or raises IndexError
+            yield counter()  # yields the fillvalue, or raises IndexError
 
         fillers = itertools.repeat(fillvalue)
         iters = [itertools.chain(it, sentinel(), fillers)