diff --git a/clientapi/producers/roomserver.go b/clientapi/producers/roomserver.go
index f537557f5..513674607 100644
--- a/clientapi/producers/roomserver.go
+++ b/clientapi/producers/roomserver.go
@@ -99,3 +99,16 @@ func (c *RoomserverProducer) SendInputRoomEvents(
 	eventID = response.EventID
 	return
 }
+
+// SendInputNewInviteEvents writes the given input new events to the roomserver input API.
+// The roomserver will automatically populate the invite room state for us before sending
+// the invite onward.
+func (c *RoomserverProducer) SendInputNewInviteEvents(
+	ctx context.Context, ires []api.InputRoomEvent,
+) (eventID string, err error) {
+	request := api.InputRoomEventsRequest{InputRoomEvents: ires}
+	var response api.InputRoomEventsResponse
+	err = c.InputAPI.InputNewInviteEvents(ctx, &request, &response)
+	eventID = response.EventID
+	return
+}
diff --git a/clientapi/routing/membership.go b/clientapi/routing/membership.go
index 9f386b718..fd29901ac 100644
--- a/clientapi/routing/membership.go
+++ b/clientapi/routing/membership.go
@@ -104,14 +104,31 @@ func SendMembership(
 		return jsonerror.InternalServerError()
 	}
 
-	if _, err := producer.SendEvents(
-		req.Context(),
-		[]gomatrixserverlib.HeaderedEvent{(*event).Headered(verRes.RoomVersion)},
-		cfg.Matrix.ServerName,
-		nil,
-	); err != nil {
-		util.GetLogger(req.Context()).WithError(err).Error("producer.SendEvents failed")
-		return jsonerror.InternalServerError()
+	if membership == gomatrixserverlib.Invite {
+		if _, err := producer.SendInputNewInviteEvents(
+			req.Context(),
+			[]api.InputRoomEvent{
+				api.InputRoomEvent{
+					Kind:         api.KindNew,
+					Event:        event.Headered(verRes.RoomVersion),
+					AuthEventIDs: event.AuthEventIDs(),
+					SendAsServer: string(cfg.Matrix.ServerName),
+				},
+			},
+		); err != nil {
+			util.GetLogger(req.Context()).WithError(err).Error("producer.SendEvents failed")
+			return jsonerror.InternalServerError()
+		}
+	} else {
+		if _, err := producer.SendEvents(
+			req.Context(),
+			[]gomatrixserverlib.HeaderedEvent{(*event).Headered(verRes.RoomVersion)},
+			cfg.Matrix.ServerName,
+			nil,
+		); err != nil {
+			util.GetLogger(req.Context()).WithError(err).Error("producer.SendEvents failed")
+			return jsonerror.InternalServerError()
+		}
 	}
 
 	var returnData interface{} = struct{}{}
diff --git a/roomserver/api/input.go b/roomserver/api/input.go
index fbedff2ed..41c741f80 100644
--- a/roomserver/api/input.go
+++ b/roomserver/api/input.go
@@ -99,10 +99,17 @@ type RoomserverInputAPI interface {
 		request *InputRoomEventsRequest,
 		response *InputRoomEventsResponse,
 	) error
+
+	InputNewInviteEvents(
+		ctx context.Context,
+		request *InputRoomEventsRequest,
+		response *InputRoomEventsResponse,
+	) error
 }
 
 // RoomserverInputRoomEventsPath is the HTTP path for the InputRoomEvents API.
 const RoomserverInputRoomEventsPath = "/api/roomserver/inputRoomEvents"
+const RoomserverInputNewInviteEventsPath = "/api/roomserver/inputRoomEvents"
 
 // NewRoomserverInputAPIHTTP creates a RoomserverInputAPI implemented by talking to a HTTP POST API.
 // If httpClient is nil an error is returned
@@ -130,3 +137,16 @@ func (h *httpRoomserverInputAPI) InputRoomEvents(
 	apiURL := h.roomserverURL + RoomserverInputRoomEventsPath
 	return commonHTTP.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
 }
+
+// InputRoomEvents implements RoomserverInputAPI
+func (h *httpRoomserverInputAPI) InputNewInviteEvents(
+	ctx context.Context,
+	request *InputRoomEventsRequest,
+	response *InputRoomEventsResponse,
+) error {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "InputNewInviteEvents")
+	defer span.Finish()
+
+	apiURL := h.roomserverURL + RoomserverInputNewInviteEventsPath
+	return commonHTTP.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+}
diff --git a/roomserver/input/events.go b/roomserver/input/events.go
index 64d696cd1..4fd5f69a3 100644
--- a/roomserver/input/events.go
+++ b/roomserver/input/events.go
@@ -280,53 +280,4 @@ func processInviteEvent(
 	succeeded = true
 	return nil
 }
-
-func buildInviteStrippedState(
-	ctx context.Context,
-	db RoomEventDatabase,
-	input api.InputInviteEvent,
-) (json.RawMessage, error) {
-	roomNID, err := db.RoomNID(ctx, input.Event.RoomID())
-	if err != nil || roomNID == 0 {
-		return nil, nil
-	}
-	stateWanted := []gomatrixserverlib.StateKeyTuple{}
-	for _, t := range []string{
-		gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias,
-		gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules,
-	} {
-		stateWanted = append(stateWanted, gomatrixserverlib.StateKeyTuple{
-			EventType: t,
-			StateKey:  "",
-		})
-	}
-	_, currentStateSnapshotNID, _, err := db.LatestEventIDs(ctx, roomNID)
-	if err != nil {
-		return nil, err
-	}
-	roomState := state.NewStateResolution(db)
-	stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples(
-		ctx, currentStateSnapshotNID, stateWanted,
-	)
-	if err != nil {
-		return nil, err
-	}
-	stateNIDs := []types.EventNID{}
-	for _, stateNID := range stateEntries {
-		stateNIDs = append(stateNIDs, stateNID.EventNID)
-	}
-	stateEvents, err := db.Events(ctx, stateNIDs)
-	if err != nil {
-		return nil, err
-	}
-	inviteState := []gomatrixserverlib.InviteV2StrippedState{}
-	for _, event := range stateEvents {
-		inviteState = append(inviteState, gomatrixserverlib.NewInviteV2StrippedState(&event.Event))
-	}
-	inviteStrippedState, err := json.Marshal(inviteState)
-	if err != nil {
-		return nil, err
-	}
-	return inviteStrippedState, nil
-}
 */
diff --git a/roomserver/input/input.go b/roomserver/input/input.go
index fb69e9014..ee3eebf0f 100644
--- a/roomserver/input/input.go
+++ b/roomserver/input/input.go
@@ -72,6 +72,24 @@ func (r *RoomserverInputAPI) InputRoomEvents(
 	return nil
 }
 
+// InputNewInviteEvents implements api.RoomserverInputAPI
+func (r *RoomserverInputAPI) InputNewInviteEvents(
+	ctx context.Context,
+	request *api.InputRoomEventsRequest,
+	response *api.InputRoomEventsResponse,
+) (err error) {
+	for i := range request.InputRoomEvents {
+		inviteRoomState, err := buildInviteStrippedState(ctx, r.DB, request.InputRoomEvents[i])
+		if err != nil {
+			return err
+		}
+		if err := request.InputRoomEvents[i].Event.SetUnsignedField("invite_room_state", inviteRoomState); err != nil {
+			return err
+		}
+	}
+	return r.InputRoomEvents(ctx, request, response)
+}
+
 // SetupHTTP adds the RoomserverInputAPI handlers to the http.ServeMux.
 func (r *RoomserverInputAPI) SetupHTTP(servMux *http.ServeMux) {
 	servMux.Handle(api.RoomserverInputRoomEventsPath,
diff --git a/roomserver/input/invites.go b/roomserver/input/invites.go
new file mode 100644
index 000000000..2217e9e7e
--- /dev/null
+++ b/roomserver/input/invites.go
@@ -0,0 +1,60 @@
+package input
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/matrix-org/dendrite/roomserver/api"
+	"github.com/matrix-org/dendrite/roomserver/state"
+	"github.com/matrix-org/dendrite/roomserver/types"
+	"github.com/matrix-org/gomatrixserverlib"
+)
+
+func buildInviteStrippedState(
+	ctx context.Context,
+	db RoomEventDatabase,
+	input api.InputRoomEvent,
+) (json.RawMessage, error) {
+	roomNID, err := db.RoomNID(ctx, input.Event.RoomID())
+	if err != nil || roomNID == 0 {
+		return nil, nil
+	}
+	stateWanted := []gomatrixserverlib.StateKeyTuple{}
+	for _, t := range []string{
+		gomatrixserverlib.MRoomName, gomatrixserverlib.MRoomCanonicalAlias,
+		gomatrixserverlib.MRoomAliases, gomatrixserverlib.MRoomJoinRules,
+	} {
+		stateWanted = append(stateWanted, gomatrixserverlib.StateKeyTuple{
+			EventType: t,
+			StateKey:  "",
+		})
+	}
+	_, currentStateSnapshotNID, _, err := db.LatestEventIDs(ctx, roomNID)
+	if err != nil {
+		return nil, err
+	}
+	roomState := state.NewStateResolution(db)
+	stateEntries, err := roomState.LoadStateAtSnapshotForStringTuples(
+		ctx, currentStateSnapshotNID, stateWanted,
+	)
+	if err != nil {
+		return nil, err
+	}
+	stateNIDs := []types.EventNID{}
+	for _, stateNID := range stateEntries {
+		stateNIDs = append(stateNIDs, stateNID.EventNID)
+	}
+	stateEvents, err := db.Events(ctx, stateNIDs)
+	if err != nil {
+		return nil, err
+	}
+	inviteState := []gomatrixserverlib.InviteV2StrippedState{}
+	for _, event := range stateEvents {
+		inviteState = append(inviteState, gomatrixserverlib.NewInviteV2StrippedState(&event.Event))
+	}
+	inviteStrippedState, err := json.Marshal(inviteState)
+	if err != nil {
+		return nil, err
+	}
+	return inviteStrippedState, nil
+}