diff --git a/config.py b/config.py
index 48216d1e3..c0ac210e9 100644
--- a/config.py
+++ b/config.py
@@ -503,3 +503,7 @@ class DefaultConfig(ImmutableConfig):
 
   # The size of pages returned by the Docker V2 API.
   V2_PAGINATION_SIZE = 50
+  
+  # If enabled, ensures that API calls are made with the X-Requested-With header
+  # when called from a browser.
+  BROWSER_API_CALLS_XHR_ONLY = True
diff --git a/endpoints/api/__init__.py b/endpoints/api/__init__.py
index e79263cf8..f0d59913e 100644
--- a/endpoints/api/__init__.py
+++ b/endpoints/api/__init__.py
@@ -21,7 +21,7 @@ from auth.decorators import process_oauth
 from endpoints.csrf import csrf_protect
 from endpoints.exception import (Unauthorized, InvalidRequest, InvalidResponse,
                                  FreshLoginRequired, NotFound)
-from endpoints.decorators import check_anon_protection
+from endpoints.decorators import check_anon_protection, require_xhr_from_browser
 from util.metrics.metricqueue import time_decorator
 from util.names import parse_namespace_repository
 from util.pagination import encrypt_page_token, decrypt_page_token
@@ -42,7 +42,8 @@ api = ApiExceptionHandlingApi()
 api.init_app(api_bp)
 api.decorators = [csrf_protect(),
                   crossdomain(origin='*', headers=['Authorization', 'Content-Type']),
-                  process_oauth, time_decorator(api_bp.name, metric_queue)]
+                  process_oauth, time_decorator(api_bp.name, metric_queue),
+                  require_xhr_from_browser]
 
 
 def resource(*urls, **kwargs):
diff --git a/endpoints/decorators.py b/endpoints/decorators.py
index 725dcf316..3e91a074c 100644
--- a/endpoints/decorators.py
+++ b/endpoints/decorators.py
@@ -1,5 +1,7 @@
 """ Various decorators for endpoint and API handlers. """
 
+import logging
+
 from functools import wraps
 from flask import abort, request, make_response
 
@@ -8,6 +10,9 @@ import features
 from app import app
 from auth.auth_context import get_authenticated_context
 from util.names import parse_namespace_repository
+from util.http import abort
+
+logger = logging.getLogger(__name__)
 
 
 def parse_repository_name(include_tag=False,
@@ -92,3 +97,22 @@ def route_show_if(value):
       return f(*args, **kwargs)
     return decorated_function
   return decorator
+
+
+def require_xhr_from_browser(func):
+  """ Requires that API GET calls made from browsers are made via XHR, in order to prevent
+      reflected text attacks.
+  """
+
+  @wraps(func)
+  def wrapper(*args, **kwargs):
+    if app.config.get('BROWSER_API_CALLS_XHR_ONLY', False):
+      if request.method == 'GET' and request.user_agent.browser:
+        has_xhr_header = request.headers.get('X-Requested-With') == 'XMLHttpRequest'
+        if not has_xhr_header:
+          logger.warning('Disallowed possible RTA to URL %s with user agent %s',
+                        request.path, request.user_agent)
+          abort(400)
+
+    return func(*args, **kwargs)
+  return wrapper
diff --git a/endpoints/test/test_decorators.py b/endpoints/test/test_decorators.py
new file mode 100644
index 000000000..e7866e25d
--- /dev/null
+++ b/endpoints/test/test_decorators.py
@@ -0,0 +1,35 @@
+from data import model
+from endpoints.api import api
+from endpoints.api.repository import Repository
+from endpoints.test.shared import conduct_call
+from test.fixtures import *
+
+
+@pytest.mark.parametrize('user_agent, include_header, expected_code', [
+  ('curl/whatever', True, 200),
+  ('curl/whatever', False, 200),
+
+  ('Mozilla/whatever', True, 200),
+  ('Mozilla/5.0', True, 200),
+  ('Mozilla/5.0 (Windows NT 5.1; Win64; x64)', False, 400),
+])
+def test_require_xhr_from_browser(user_agent, include_header, expected_code, app, client):
+  # Create a public repo with a dot in its name.
+  user = model.user.get_user('devtable')
+  model.repository.create_repository('devtable', 'somerepo.bat', user, 'public')
+
+  # Retrieve the repository and ensure we either allow it through or fail, depending on the
+  # user agent and header.
+  params = {
+    'repository': 'devtable/somerepo.bat'
+  }
+
+  headers = {
+    'User-Agent': user_agent,
+  }
+
+  if include_header:
+    headers['X-Requested-With'] = 'XMLHttpRequest'
+
+  conduct_call(client, Repository, api.url_for, 'GET', params, headers=headers,
+               expected_code=expected_code)
diff --git a/static/js/quay-run.ts b/static/js/quay-run.ts
index c0815ef68..3df58baf0 100644
--- a/static/js/quay-run.ts
+++ b/static/js/quay-run.ts
@@ -11,6 +11,7 @@ provideRun.$inject = [
   'PlanService',
   '$http',
   'CookieService',
+  'UserService',
   'Features',
   '$anchorScroll',
   'MetaService',
@@ -20,6 +21,7 @@ export function provideRun($rootScope: QuayRunScope,
                            planService: any,
                            $http: ng.IHttpService,
                            cookieService: any,
+                           userService: any,
                            features: any,
                            $anchorScroll: ng.IAnchorScrollService,
                            metaService: any): void {
@@ -29,6 +31,8 @@ export function provideRun($rootScope: QuayRunScope,
   restangular.setDefaultRequestParams(['post', 'put', 'remove', 'delete'],
     {'_csrf_token': (<any>window).__token || ''});
 
+  restangular.setDefaultHeaders({'X-Requested-With': 'XMLHttpRequest'});
+
   // Handle session expiration.
   restangular.setErrorInterceptor(function(response) {
     if (response !== undefined && response.status == 503) {
@@ -120,6 +124,9 @@ export function provideRun($rootScope: QuayRunScope,
     }
     return $http.pendingRequests.length > 0;
   };
+
+  // Load the inital user information.
+  userService.load();
 }
 
 
diff --git a/static/js/services/user-service.js b/static/js/services/user-service.js
index 64e75828b..1196bf030 100644
--- a/static/js/services/user-service.js
+++ b/static/js/services/user-service.js
@@ -251,8 +251,5 @@ function(ApiService, CookieService, $rootScope, Config, $location, $timeout) {
   // Update the user in the root scope.
   userService.updateUserIn($rootScope);
 
-  // Load the user the first time.
-  userService.load();
-
   return userService;
 }]);
diff --git a/test/registry_tests.py b/test/registry_tests.py
index 5e880c85c..a897968cf 100644
--- a/test/registry_tests.py
+++ b/test/registry_tests.py
@@ -786,14 +786,11 @@ class V2RegistryLoginMixin(object):
 
 class RegistryTestsMixin(object):
   def test_previously_bad_repo_name(self):
-    bad_names = ['logs', 'build', 'tokens', 'foo.bar', 'foo-bar', 'foo_bar']
+    # Push a new repository with two layers.
+    self.do_push('public', 'foo.bar', 'public', 'password')
 
-    for name in bad_names:
-      # Push a new repository with two layers.
-      self.do_push('public', name, 'public', 'password')
-
-      # Pull the repository to verify.
-      self.do_pull('public', name, 'public', 'password')
+    # Pull the repository to verify.
+    self.do_pull('public', 'foo.bar', 'public', 'password')
 
   def test_application_repo(self):
     # Create an application repository via the API.
diff --git a/util/config/schema.py b/util/config/schema.py
index 7fcc11d9c..64b8e58f4 100644
--- a/util/config/schema.py
+++ b/util/config/schema.py
@@ -591,6 +591,11 @@ CONFIG_SCHEMA = {
                      'not authenticated as a superuser',
       'x-example': 'somesecrethere',
     },
+    'BROWSER_API_CALLS_XHR_ONLY': {
+      'type': 'boolean',
+      'description': 'If enabled, only API calls marked as being made by an XHR will be allowed from browsers. Defaults to True.',
+      'x-example': False,
+    },
 
     # Time machine and tag expiration settings.
     'FEATURE_CHANGE_TAG_EXPIRATION': {