diff --git a/proto/user_pb2.py b/proto/user_pb2.py
new file mode 100644
index 0000000..c3191ed
--- /dev/null
+++ b/proto/user_pb2.py
@@ -0,0 +1,97 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Protocol buffers for Monorail users."""
+
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+from protorpc import messages
+
+
+class IssueUpdateNav(messages.Enum):
+  """Pref for where a project member goes after an issue update."""
+  UP_TO_LIST = 0       # Back to issue list or grid view.
+  STAY_SAME_ISSUE = 1  # Show the same issue with the update.
+  NEXT_IN_LIST = 2     # Triage mode: go to next issue, if any.
+
+
+class User(messages.Message):
+  """In-memory busines object for representing users."""
+  user_id = messages.IntegerField(1)  # TODO(jrobbins): make it required.
+
+  # Is this user a site administer?
+  is_site_admin = messages.BooleanField(4, required=True, default=False)
+
+  # User notification preferences.  These preferences describe when
+  # a user is sent a email notification after an issue has changed.
+  # The user is notified if either of the following is true:
+  # 1. notify_issue_change is True and the user is named in the
+  # issue's Owner or CC field.
+  # 2. notify_starred_issue_change is True and the user has starred
+  # the issue.
+  notify_issue_change = messages.BooleanField(5, default=True)
+  notify_starred_issue_change = messages.BooleanField(6, default=True)
+  # Opt-in to email subject lines like "proj:123: issue summary".
+  email_compact_subject = messages.BooleanField(14, default=False)
+  # Opt-out of "View Issue" button in Gmail inbox.
+  email_view_widget = messages.BooleanField(15, default=True)
+  # Opt-in to ping emails from issues that the user starred.
+  notify_starred_ping = messages.BooleanField(16, default=False)
+
+  # This user has been banned, and this string describes why. All access
+  # to Monorail pages should be disabled.
+  banned = messages.StringField(7, default='')
+
+  # Fields 8-13 are no longer used: they were User action counts and limits.
+
+  after_issue_update = messages.EnumField(
+      IssueUpdateNav, 29, default=IssueUpdateNav.STAY_SAME_ISSUE)
+
+  # Should we obfuscate the user's email address and require solving a captcha
+  # to reveal it entirely? The default value corresponds to requiring users to
+  # opt into publishing their identities, but our code ensures that the
+  # opposite takes place for Gmail accounts.
+  obscure_email = messages.BooleanField(26, default=True)
+
+  # The email address chosen by the user to reveal on the site.
+  email = messages.StringField(27)
+
+  # Sticky state for show/hide widget on people details page.
+  keep_people_perms_open = messages.BooleanField(33, default=False)
+
+  deleted = messages.BooleanField(39, default=False)
+  deleted_timestamp = messages.IntegerField(40, default=0)
+
+  preview_on_hover = messages.BooleanField(42, default=True)
+
+  last_visit_timestamp = messages.IntegerField(45, default=0)
+  email_bounce_timestamp = messages.IntegerField(46, default=0)
+  vacation_message = messages.StringField(47)
+
+  linked_parent_id = messages.IntegerField(48)
+  linked_child_ids = messages.IntegerField(49, repeated=True)
+
+
+class UserPrefValue(messages.Message):
+  """Holds a single non-default user pref."""
+  name = messages.StringField(1, required=True)
+  value = messages.StringField(2)
+
+
+class UserPrefs(messages.Message):
+  """In-memory business object for representing user preferences."""
+  user_id = messages.IntegerField(1, required=True)
+  prefs = messages.MessageField(UserPrefValue, 2, repeated=True)
+
+
+
+def MakeUser(user_id, email=None, obscure_email=False):
+  """Create and return a new user record in RAM."""
+  user = User(user_id=user_id, obscure_email=bool(obscure_email))
+  if email:
+    user.email = email
+  return user