diff --git a/roomserver/api/api_trace.go b/roomserver/api/api_trace.go
index 1a2b9a49..c18279f0 100644
--- a/roomserver/api/api_trace.go
+++ b/roomserver/api/api_trace.go
@@ -208,6 +208,16 @@ func (t *RoomserverInternalAPITrace) QueryStateAndAuthChain(
 	return err
 }
 
+func (t *RoomserverInternalAPITrace) QueryStateAndAuthChainIDs(
+	ctx context.Context,
+	req *QueryStateAndAuthChainIDsRequest,
+	res *QueryStateAndAuthChainIDsResponse,
+) error {
+	err := t.Impl.QueryStateAndAuthChainIDs(ctx, req, res)
+	util.GetLogger(ctx).WithError(err).Infof("QueryStateAndAuthChainIDs req=%+v res=%+v", js(req), js(res))
+	return err
+}
+
 func (t *RoomserverInternalAPITrace) PerformBackfill(
 	ctx context.Context,
 	req *PerformBackfillRequest,
diff --git a/roomserver/inthttp/client.go b/roomserver/inthttp/client.go
index 6774d102..0ba0031d 100644
--- a/roomserver/inthttp/client.go
+++ b/roomserver/inthttp/client.go
@@ -47,6 +47,7 @@ const (
 	RoomserverQueryServerAllowedToSeeEventPath = "/roomserver/queryServerAllowedToSeeEvent"
 	RoomserverQueryMissingEventsPath           = "/roomserver/queryMissingEvents"
 	RoomserverQueryStateAndAuthChainPath       = "/roomserver/queryStateAndAuthChain"
+	RoomserverQueryStateAndAuthChainIDsPath    = "/roomserver/queryStateAndAuthChainIDs"
 	RoomserverQueryRoomVersionCapabilitiesPath = "/roomserver/queryRoomVersionCapabilities"
 	RoomserverQueryRoomVersionForRoomPath      = "/roomserver/queryRoomVersionForRoom"
 	RoomserverQueryPublishedRoomsPath          = "/roomserver/queryPublishedRooms"
@@ -417,6 +418,19 @@ func (h *httpRoomserverInternalAPI) QueryStateAndAuthChain(
 	return httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
 }
 
+// QueryStateAndAuthChainIDs implements RoomserverQueryAPI
+func (h *httpRoomserverInternalAPI) QueryStateAndAuthChainIDs(
+	ctx context.Context,
+	request *api.QueryStateAndAuthChainIDsRequest,
+	response *api.QueryStateAndAuthChainIDsResponse,
+) error {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryStateAndAuthChainIDs")
+	defer span.Finish()
+
+	apiURL := h.roomserverURL + RoomserverQueryStateAndAuthChainIDsPath
+	return httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+}
+
 // PerformBackfill implements RoomServerQueryAPI
 func (h *httpRoomserverInternalAPI) PerformBackfill(
 	ctx context.Context,
diff --git a/roomserver/inthttp/server.go b/roomserver/inthttp/server.go
index bf319262..3d7fe4b1 100644
--- a/roomserver/inthttp/server.go
+++ b/roomserver/inthttp/server.go
@@ -261,6 +261,20 @@ func AddRoutes(r api.RoomserverInternalAPI, internalAPIMux *mux.Router) {
 			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
 		}),
 	)
+	internalAPIMux.Handle(
+		RoomserverQueryStateAndAuthChainIDsPath,
+		httputil.MakeInternalAPI("queryStateAndAuthChainIDs", func(req *http.Request) util.JSONResponse {
+			var request api.QueryStateAndAuthChainIDsRequest
+			var response api.QueryStateAndAuthChainIDsResponse
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.ErrorResponse(err)
+			}
+			if err := r.QueryStateAndAuthChainIDs(req.Context(), &request, &response); err != nil {
+				return util.ErrorResponse(err)
+			}
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
 	internalAPIMux.Handle(
 		RoomserverPerformBackfillPath,
 		httputil.MakeInternalAPI("PerformBackfill", func(req *http.Request) util.JSONResponse {