diff --git a/third_party/endpoints/errors.py b/third_party/endpoints/errors.py
new file mode 100644
index 0000000..e98c76d
--- /dev/null
+++ b/third_party/endpoints/errors.py
@@ -0,0 +1,285 @@
+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Error handling and exceptions used in the local Cloud Endpoints server."""
+
+# pylint: disable=g-bad-name
+from __future__ import absolute_import
+
+import json
+import logging
+
+from . import generated_error_info
+
+__all__ = ['BackendError',
+           'BasicTypeParameterError',
+           'EnumRejectionError',
+           'InvalidParameterError',
+           'RequestError',
+           'RequestRejectionError']
+
+_logger = logging.getLogger(__name__)
+
+_INVALID_ENUM_TEMPLATE = 'Invalid string value: %r. Allowed values: %r'
+_INVALID_BASIC_PARAM_TEMPLATE = 'Invalid %s value: %r.'
+
+
+class RequestError(Exception):
+  """Base class for errors that happen while processing a request."""
+
+  def status_code(self):
+    """HTTP status code number associated with this error.
+
+    Subclasses must implement this, returning an integer with the status
+    code number for the error.
+
+    Example: 400
+
+    Raises:
+      NotImplementedError: Subclasses must override this function.
+    """
+    raise NotImplementedError
+
+  def message(self):
+    """Text message explaining the error.
+
+    Subclasses must implement this, returning a string that explains the
+    error.
+
+    Raises:
+      NotImplementedError: Subclasses must override this function.
+    """
+    raise NotImplementedError
+
+  def reason(self):
+    """Get the reason for the error.
+
+    Error reason is a custom string in the Cloud Endpoints server.  When
+    possible, this should match the reason that the live server will generate,
+    based on the error's status code.  If this returns None, the error formatter
+    will attempt to generate a reason from the status code.
+
+    Returns:
+      None, by default.  Subclasses can override this if they have a specific
+      error reason.
+    """
+    raise NotImplementedError
+
+  def domain(self):
+    """Get the domain for this error.
+
+    Returns:
+      The string 'global' by default.  Subclasses can override this if they have
+      a different domain.
+    """
+    return 'global'
+
+  def extra_fields(self):
+    """Return a dict of extra fields to add to the error response.
+
+    Some errors have additional information.  This provides a way for subclasses
+    to provide that information.
+
+    Returns:
+      None, by default.  Subclasses can return a dict with values to add
+      to the error response.
+    """
+    return None
+
+  def __format_error(self, error_list_tag):
+    """Format this error into a JSON response.
+
+    Args:
+      error_list_tag: A string specifying the name of the tag to use for the
+        error list.
+
+    Returns:
+      A dict containing the reformatted JSON error response.
+    """
+    error = {'domain': self.domain(),
+             'reason': self.reason(),
+             'message': self.message()}
+    error.update(self.extra_fields() or {})
+    return {'error': {error_list_tag: [error],
+                      'code': self.status_code(),
+                      'message': self.message()}}
+
+  def rest_error(self):
+    """Format this error into a response to a REST request.
+
+    Returns:
+      A string containing the reformatted error response.
+    """
+    error_json = self.__format_error('errors')
+    return json.dumps(error_json, indent=1, sort_keys=True)
+
+  def rpc_error(self):
+    """Format this error into a response to a JSON RPC request.
+
+
+    Returns:
+      A dict containing the reformatted JSON error response.
+    """
+    return self.__format_error('data')
+
+
+class RequestRejectionError(RequestError):
+  """Base class for invalid/rejected requests.
+
+  To be raised when parsing the request values and comparing them against the
+  generated discovery document.
+  """
+
+  def status_code(self):
+    return 400
+
+
+class InvalidParameterError(RequestRejectionError):
+  """Base class for invalid parameter errors.
+
+  Child classes only need to implement the message() function.
+  """
+
+  def __init__(self, parameter_name, value):
+    """Constructor for InvalidParameterError.
+
+    Args:
+      parameter_name: String; the name of the parameter which had a value
+        rejected.
+      value: The actual value passed in for the parameter. Usually string.
+    """
+    super(InvalidParameterError, self).__init__()
+    self.parameter_name = parameter_name
+    self.value = value
+
+  def reason(self):
+    """Returns the server's reason for this error.
+
+    Returns:
+      A string containing a short error reason.
+    """
+    return 'invalidParameter'
+
+  def extra_fields(self):
+    """Returns extra fields to add to the error response.
+
+    Returns:
+      A dict containing extra fields to add to the error response.
+    """
+    return {'locationType': 'parameter',
+            'location': self.parameter_name}
+
+
+class BasicTypeParameterError(InvalidParameterError):
+  """Request rejection exception for basic types (int, float)."""
+
+  def __init__(self, parameter_name, value, type_name):
+    """Constructor for BasicTypeParameterError.
+
+    Args:
+      parameter_name: String; the name of the parameter which had a value
+        rejected.
+      value: The actual value passed in for the enum. Usually string.
+      type_name: Descriptive name of the data type expected.
+    """
+    super(BasicTypeParameterError, self).__init__(parameter_name, value)
+    self.type_name = type_name
+
+  def message(self):
+    """A descriptive message describing the error."""
+    return _INVALID_BASIC_PARAM_TEMPLATE % (self.type_name, self.value)
+
+
+class EnumRejectionError(InvalidParameterError):
+  """Custom request rejection exception for enum values."""
+
+  def __init__(self, parameter_name, value, allowed_values):
+    """Constructor for EnumRejectionError.
+
+    Args:
+      parameter_name: String; the name of the enum parameter which had a value
+        rejected.
+      value: The actual value passed in for the enum. Usually string.
+      allowed_values: List of strings allowed for the enum.
+    """
+    super(EnumRejectionError, self).__init__(parameter_name, value)
+    self.allowed_values = allowed_values
+
+  def message(self):
+    """A descriptive message describing the error."""
+    return _INVALID_ENUM_TEMPLATE % (self.value, self.allowed_values)
+
+
+class BackendError(RequestError):
+  """Exception raised when the backend returns an error code."""
+
+  def __init__(self, body, status):
+    super(BackendError, self).__init__()
+    # Convert backend error status to whatever the live server would return.
+    status_code = self._get_status_code(status)
+    self._error_info = generated_error_info.get_error_info(status_code)
+
+    try:
+      error_json = json.loads(body)
+      self._message = error_json.get('error_message')
+    except TypeError:
+      self._message = body
+
+  def _get_status_code(self, http_status):
+    """Get the HTTP status code from an HTTP status string.
+
+    Args:
+      http_status: A string containing a HTTP status code and reason.
+
+    Returns:
+      An integer with the status code number from http_status.
+    """
+    try:
+      return int(http_status.split(' ', 1)[0])
+    except TypeError:
+      _logger.warning('Unable to find status code in HTTP status %r.',
+                      http_status)
+    return 500
+
+  def status_code(self):
+    """Return the HTTP status code number for this error.
+
+    Returns:
+      An integer containing the status code for this error.
+    """
+    return self._error_info.http_status
+
+  def message(self):
+    """Return a descriptive message for this error.
+
+    Returns:
+      A string containing a descriptive message for this error.
+    """
+    return self._message
+
+  def reason(self):
+    """Return the short reason for this error.
+
+    Returns:
+      A string with the reason for this error.
+    """
+    return self._error_info.reason
+
+  def domain(self):
+    """Return the remapped domain for this error.
+
+    Returns:
+      A string containing the remapped domain for this error.
+    """
+    return self._error_info.domain