diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index bde9b51b2..126a10efb 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -88,6 +88,8 @@ class ApplicationService(object):
         self.sender = sender
         self.namespaces = self._check_namespaces(namespaces)
         self.id = id
+
+        # .protocols is a publicly visible field
         if protocols:
             self.protocols = set(protocols)
         else:
diff --git a/synapse/appservice/api.py b/synapse/appservice/api.py
index 066127b66..d28a9dff0 100644
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -17,6 +17,7 @@ from twisted.internet import defer
 from synapse.api.errors import CodeMessageException
 from synapse.http.client import SimpleHttpClient
 from synapse.events.utils import serialize_event
+from synapse.util.caches.response_cache import ResponseCache
 from synapse.types import ThirdPartyEntityKind
 
 import logging
@@ -25,6 +26,9 @@ import urllib
 logger = logging.getLogger(__name__)
 
 
+HOUR_IN_MS = 60 * 60 * 1000
+
+
 def _is_valid_3pe_result(r, field):
     if not isinstance(r, dict):
         return False
@@ -56,6 +60,8 @@ class ApplicationServiceApi(SimpleHttpClient):
         super(ApplicationServiceApi, self).__init__(hs)
         self.clock = hs.get_clock()
 
+        self.protocol_meta_cache = ResponseCache(hs, timeout_ms=HOUR_IN_MS)
+
     @defer.inlineCallbacks
     def query_user(self, service, user_id):
         uri = service.url + ("/users/%s" % urllib.quote(user_id))
@@ -97,10 +103,10 @@ class ApplicationServiceApi(SimpleHttpClient):
     @defer.inlineCallbacks
     def query_3pe(self, service, kind, protocol, fields):
         if kind == ThirdPartyEntityKind.USER:
-            uri = "%s/3pu/%s" % (service.url, urllib.quote(protocol))
+            uri = "%s/thirdparty/user/%s" % (service.url, urllib.quote(protocol))
             required_field = "userid"
         elif kind == ThirdPartyEntityKind.LOCATION:
-            uri = "%s/3pl/%s" % (service.url, urllib.quote(protocol))
+            uri = "%s/thirdparty/location/%s" % (service.url, urllib.quote(protocol))
             required_field = "alias"
         else:
             raise ValueError(
@@ -131,6 +137,22 @@ class ApplicationServiceApi(SimpleHttpClient):
             logger.warning("query_3pe to %s threw exception %s", uri, ex)
             defer.returnValue([])
 
+    def get_3pe_protocol(self, service, protocol):
+        @defer.inlineCallbacks
+        def _get():
+            uri = "%s/thirdparty/protocol/%s" % (service.url, urllib.quote(protocol))
+            try:
+                defer.returnValue((yield self.get_json(uri, {})))
+            except Exception as ex:
+                logger.warning("query_3pe_protocol to %s threw exception %s",
+                               uri, ex)
+                defer.returnValue({})
+
+        key = (service.id, protocol)
+        return self.protocol_meta_cache.get(key) or (
+            self.protocol_meta_cache.set(key, _get())
+        )
+
     @defer.inlineCallbacks
     def push_bulk(self, service, events, txn_id=None):
         events = self._serialize(events)
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 306686a38..b440280b7 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -175,6 +175,16 @@ class ApplicationServicesHandler(object):
 
         defer.returnValue(ret)
 
+    @defer.inlineCallbacks
+    def get_3pe_protocols(self):
+        services = yield self.store.get_app_services()
+        protocols = {}
+        for s in services:
+            for p in s.protocols:
+                protocols[p] = yield self.appservice_api.get_3pe_protocol(s, p)
+
+        defer.returnValue(protocols)
+
     @defer.inlineCallbacks
     def _get_services_for_event(self, event):
         """Retrieve a list of application services interested in this event.
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index 9abca3a8a..bbc3e9b96 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -25,8 +25,25 @@ from ._base import client_v2_patterns
 logger = logging.getLogger(__name__)
 
 
+class ThirdPartyProtocolsServlet(RestServlet):
+    PATTERNS = client_v2_patterns("/thirdparty/protocols", releases=())
+
+    def __init__(self, hs):
+        super(ThirdPartyProtocolsServlet, self).__init__()
+
+        self.auth = hs.get_auth()
+        self.appservice_handler = hs.get_application_service_handler()
+
+    @defer.inlineCallbacks
+    def on_GET(self, request):
+        yield self.auth.get_user_by_req(request)
+
+        protocols = yield self.appservice_handler.get_3pe_protocols()
+        defer.returnValue((200, protocols))
+
+
 class ThirdPartyUserServlet(RestServlet):
-    PATTERNS = client_v2_patterns("/3pu(/(?P<protocol>[^/]+))?$",
+    PATTERNS = client_v2_patterns("/thirdparty/user(/(?P<protocol>[^/]+))?$",
                                   releases=())
 
     def __init__(self, hs):
@@ -50,7 +67,7 @@ class ThirdPartyUserServlet(RestServlet):
 
 
 class ThirdPartyLocationServlet(RestServlet):
-    PATTERNS = client_v2_patterns("/3pl(/(?P<protocol>[^/]+))?$",
+    PATTERNS = client_v2_patterns("/thirdparty/location(/(?P<protocol>[^/]+))?$",
                                   releases=())
 
     def __init__(self, hs):
@@ -74,5 +91,6 @@ class ThirdPartyLocationServlet(RestServlet):
 
 
 def register_servlets(hs, http_server):
+    ThirdPartyProtocolsServlet(hs).register(http_server)
     ThirdPartyUserServlet(hs).register(http_server)
     ThirdPartyLocationServlet(hs).register(http_server)