diff --git a/rhodecode/lib/middleware/simplegit.py b/rhodecode/lib/middleware/simplegit.py
--- a/rhodecode/lib/middleware/simplegit.py
+++ b/rhodecode/lib/middleware/simplegit.py
@@ -76,7 +76,8 @@ class SimpleGit(simplevcs.SimpleVCS):
         return 'pull'
 
     def _create_wsgi_app(self, repo_path, repo_name, config):
-        return self.scm_app.create_git_wsgi_app(repo_path, repo_name, config)
+        return self.scm_app.create_git_wsgi_app(
+            repo_path, repo_name, config, self.SCM)
 
     def _create_config(self, extras, repo_name):
         extras['git_update_server_info'] = utils2.str2bool(
diff --git a/rhodecode/lib/middleware/simplehg.py b/rhodecode/lib/middleware/simplehg.py
--- a/rhodecode/lib/middleware/simplehg.py
+++ b/rhodecode/lib/middleware/simplehg.py
@@ -71,7 +71,8 @@ class SimpleHg(simplevcs.SimpleVCS):
         return 'pull'
 
     def _create_wsgi_app(self, repo_path, repo_name, config):
-        return self.scm_app.create_hg_wsgi_app(repo_path, repo_name, config)
+        return self.scm_app.create_hg_wsgi_app(
+            repo_path, repo_name, config, self.SCM)
 
     def _create_config(self, extras, repo_name):
         config = utils.make_db_config(repo=repo_name)
diff --git a/rhodecode/lib/middleware/utils/scm_app.py b/rhodecode/lib/middleware/utils/scm_app.py
--- a/rhodecode/lib/middleware/utils/scm_app.py
+++ b/rhodecode/lib/middleware/utils/scm_app.py
@@ -34,7 +34,7 @@ HG_REMOTE_WSGI = None
 GIT_REMOTE_WSGI = None
 
 
-def create_git_wsgi_app(repo_path, repo_name, config):
+def create_git_wsgi_app(repo_path, repo_name, config, backend):
     """
     Return a WSGI app backed by a remote app to handle Git.
 
@@ -45,10 +45,10 @@ def create_git_wsgi_app(repo_path, repo_
         log.error('Pyro server has not been initialized yet')
 
     return wsgi_app_caller_client.RemoteAppCaller(
-        factory, repo_path, repo_name, config)
+        factory, backend, repo_path, repo_name, config)
 
 
-def create_hg_wsgi_app(repo_path, repo_name, config):
+def create_hg_wsgi_app(repo_path, repo_name, config, backend):
     """
     Return a WSGI app backed by a remote app to handle Mercurial.
 
@@ -60,4 +60,4 @@ def create_hg_wsgi_app(repo_path, repo_n
         log.error('Pyro server has not been initialized yet')
 
     return wsgi_app_caller_client.RemoteAppCaller(
-        factory, repo_path, repo_name, config)
+        factory, backend, repo_path, repo_name, config)
diff --git a/rhodecode/lib/middleware/utils/scm_app_http.py b/rhodecode/lib/middleware/utils/scm_app_http.py
--- a/rhodecode/lib/middleware/utils/scm_app_http.py
+++ b/rhodecode/lib/middleware/utils/scm_app_http.py
@@ -37,14 +37,14 @@ import rhodecode
 log = logging.getLogger(__name__)
 
 
-def create_git_wsgi_app(repo_path, repo_name, config):
+def create_git_wsgi_app(repo_path, repo_name, config, backend):
     url = _vcs_streaming_url() + 'git/'
-    return VcsHttpProxy(url, repo_path, repo_name, config, 'git')
+    return VcsHttpProxy(url, repo_path, repo_name, config, backend)
 
 
-def create_hg_wsgi_app(repo_path, repo_name, config):
+def create_hg_wsgi_app(repo_path, repo_name, config, backend):
     url = _vcs_streaming_url() + 'hg/'
-    return VcsHttpProxy(url, repo_path, repo_name, config, 'hg')
+    return VcsHttpProxy(url, repo_path, repo_name, config, backend)
 
 
 def _vcs_streaming_url():
diff --git a/rhodecode/lib/middleware/utils/wsgi_app_caller_client.py b/rhodecode/lib/middleware/utils/wsgi_app_caller_client.py
--- a/rhodecode/lib/middleware/utils/wsgi_app_caller_client.py
+++ b/rhodecode/lib/middleware/utils/wsgi_app_caller_client.py
@@ -56,16 +56,18 @@ class RemoteAppCaller(object):
     It first cleans the environment, so as to reduce the data transferred.
     """
 
-    def __init__(self, remote_wsgi, *args, **kwargs):
+    def __init__(self, remote_wsgi, backend, *args, **kwargs):
         """
         :param remote_wsgi: The remote wsgi object that creates a
           WSGIAppCaller. This object
           has to have a handle method, with the signature:
           handle(environ, start_response, *args, **kwargs)
+        :param backend: Key (str) of the SCM backend that is in use.
         :param args: args to be passed to the app creation
         :param kwargs: kwargs to be passed to the app creation
         """
         self._remote_wsgi = remote_wsgi
+        self._backend = backend
         self._args = args
         self._kwargs = kwargs
 
@@ -92,6 +94,10 @@ class RemoteAppCaller(object):
             data, status, headers = self._remote_wsgi.handle(
                 clean_environ, input_data, *self._args, **self._kwargs)
 
+        # Add custom response header to indicate that this is a VCS response
+        # and which backend is used.
+        headers.append(('X-RhodeCode-Backend', self._backend))
+
         log.debug("Got result from proxy, returning to WSGI container")
         start_response(status, headers)
 
diff --git a/rhodecode/tests/lib/middleware/mock_scm_app.py b/rhodecode/tests/lib/middleware/mock_scm_app.py
--- a/rhodecode/tests/lib/middleware/mock_scm_app.py
+++ b/rhodecode/tests/lib/middleware/mock_scm_app.py
@@ -27,11 +27,11 @@ for testing purposes.
 import mock
 
 
-def create_git_wsgi_app(repo_path, repo_name, config):
+def create_git_wsgi_app(repo_path, repo_name, config, backend):
     return mock_git_wsgi
 
 
-def create_hg_wsgi_app(repo_path, repo_name, config):
+def create_hg_wsgi_app(repo_path, repo_name, config, backend):
     return mock_hg_wsgi