diff --git a/src/github.com/matrix-org/dendrite/clientapi/producers/roomserver.go b/src/github.com/matrix-org/dendrite/clientapi/producers/roomserver.go
index 4e02fac5..e7a8497f 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/producers/roomserver.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/producers/roomserver.go
@@ -36,14 +36,16 @@ func NewRoomserverProducer(inputAPI api.RoomserverInputAPI) *RoomserverProducer
 // SendEvents writes the given events to the roomserver input log. The events are written with KindNew.
 func (c *RoomserverProducer) SendEvents(
 	ctx context.Context, events []gomatrixserverlib.Event, sendAsServer gomatrixserverlib.ServerName,
+	txnID *api.TransactionID,
 ) error {
 	ires := make([]api.InputRoomEvent, len(events))
 	for i, event := range events {
 		ires[i] = api.InputRoomEvent{
-			Kind:         api.KindNew,
-			Event:        event,
-			AuthEventIDs: event.AuthEventIDs(),
-			SendAsServer: string(sendAsServer),
+			Kind:          api.KindNew,
+			Event:         event,
+			AuthEventIDs:  event.AuthEventIDs(),
+			SendAsServer:  string(sendAsServer),
+			TransactionID: txnID,
 		}
 	}
 	return c.SendInputRoomEvents(ctx, ires)
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/createroom.go b/src/github.com/matrix-org/dendrite/clientapi/routing/createroom.go
index c84c1f7c..e495e448 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/createroom.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/createroom.go
@@ -214,7 +214,7 @@ func createRoom(req *http.Request, device *authtypes.Device,
 	}
 
 	// send events to the room server
-	err = producer.SendEvents(req.Context(), builtEvents, cfg.Matrix.ServerName)
+	err = producer.SendEvents(req.Context(), builtEvents, cfg.Matrix.ServerName, nil)
 	if err != nil {
 		return httputil.LogThenError(req, err)
 	}
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/joinroom.go b/src/github.com/matrix-org/dendrite/clientapi/routing/joinroom.go
index 73a751ac..aba49cd6 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/joinroom.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/joinroom.go
@@ -217,7 +217,7 @@ func (r joinRoomReq) joinRoomUsingServers(
 	var queryRes api.QueryLatestEventsAndStateResponse
 	event, err := common.BuildEvent(r.req.Context(), &eb, r.cfg, r.queryAPI, &queryRes)
 	if err == nil {
-		if err = r.producer.SendEvents(r.req.Context(), []gomatrixserverlib.Event{*event}, r.cfg.Matrix.ServerName); err != nil {
+		if err = r.producer.SendEvents(r.req.Context(), []gomatrixserverlib.Event{*event}, r.cfg.Matrix.ServerName, nil); err != nil {
 			return httputil.LogThenError(r.req, err)
 		}
 		return util.JSONResponse{
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/membership.go b/src/github.com/matrix-org/dendrite/clientapi/routing/membership.go
index e94fbde7..8e2e87ad 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/membership.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/membership.go
@@ -98,7 +98,7 @@ func SendMembership(
 	}
 
 	if err := producer.SendEvents(
-		req.Context(), []gomatrixserverlib.Event{*event}, cfg.Matrix.ServerName,
+		req.Context(), []gomatrixserverlib.Event{*event}, cfg.Matrix.ServerName, nil,
 	); err != nil {
 		return httputil.LogThenError(req, err)
 	}
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/profile.go b/src/github.com/matrix-org/dendrite/clientapi/routing/profile.go
index 1403a829..ddbae50c 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/profile.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/profile.go
@@ -138,7 +138,7 @@ func SetAvatarURL(
 		return httputil.LogThenError(req, err)
 	}
 
-	if err := rsProducer.SendEvents(req.Context(), events, cfg.Matrix.ServerName); err != nil {
+	if err := rsProducer.SendEvents(req.Context(), events, cfg.Matrix.ServerName, nil); err != nil {
 		return httputil.LogThenError(req, err)
 	}
 
@@ -230,7 +230,7 @@ func SetDisplayName(
 		return httputil.LogThenError(req, err)
 	}
 
-	if err := rsProducer.SendEvents(req.Context(), events, cfg.Matrix.ServerName); err != nil {
+	if err := rsProducer.SendEvents(req.Context(), events, cfg.Matrix.ServerName, nil); err != nil {
 		return httputil.LogThenError(req, err)
 	}
 
diff --git a/src/github.com/matrix-org/dendrite/clientapi/routing/sendevent.go b/src/github.com/matrix-org/dendrite/clientapi/routing/sendevent.go
index dc2f58f6..bc830f38 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/routing/sendevent.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/routing/sendevent.go
@@ -92,7 +92,7 @@ func SendEvent(
 
 	// pass the new event to the roomserver
 	if err := producer.SendEvents(
-		req.Context(), []gomatrixserverlib.Event{*e}, cfg.Matrix.ServerName,
+		req.Context(), []gomatrixserverlib.Event{*e}, cfg.Matrix.ServerName, nil,
 	); err != nil {
 		return httputil.LogThenError(req, err)
 	}
diff --git a/src/github.com/matrix-org/dendrite/clientapi/threepid/invites.go b/src/github.com/matrix-org/dendrite/clientapi/threepid/invites.go
index ea998e34..84ba2764 100644
--- a/src/github.com/matrix-org/dendrite/clientapi/threepid/invites.go
+++ b/src/github.com/matrix-org/dendrite/clientapi/threepid/invites.go
@@ -355,5 +355,5 @@ func emit3PIDInviteEvent(
 		return err
 	}
 
-	return producer.SendEvents(ctx, []gomatrixserverlib.Event{*event}, cfg.Matrix.ServerName)
+	return producer.SendEvents(ctx, []gomatrixserverlib.Event{*event}, cfg.Matrix.ServerName, nil)
 }
diff --git a/src/github.com/matrix-org/dendrite/federationapi/routing/join.go b/src/github.com/matrix-org/dendrite/federationapi/routing/join.go
index b52174a8..585c74e6 100644
--- a/src/github.com/matrix-org/dendrite/federationapi/routing/join.go
+++ b/src/github.com/matrix-org/dendrite/federationapi/routing/join.go
@@ -169,7 +169,7 @@ func SendJoin(
 	// Send the events to the room server.
 	// We are responsible for notifying other servers that the user has joined
 	// the room, so set SendAsServer to cfg.Matrix.ServerName
-	err = producer.SendEvents(ctx, []gomatrixserverlib.Event{event}, cfg.Matrix.ServerName)
+	err = producer.SendEvents(ctx, []gomatrixserverlib.Event{event}, cfg.Matrix.ServerName, nil)
 	if err != nil {
 		return httputil.LogThenError(httpReq, err)
 	}
diff --git a/src/github.com/matrix-org/dendrite/federationapi/routing/send.go b/src/github.com/matrix-org/dendrite/federationapi/routing/send.go
index 2103c2b8..cbffd4cc 100644
--- a/src/github.com/matrix-org/dendrite/federationapi/routing/send.go
+++ b/src/github.com/matrix-org/dendrite/federationapi/routing/send.go
@@ -170,7 +170,7 @@ func (t *txnReq) processEvent(e gomatrixserverlib.Event) error {
 	// TODO: Check that the event is allowed by its auth_events.
 
 	// pass the event to the roomserver
-	return t.producer.SendEvents(t.context, []gomatrixserverlib.Event{e}, api.DoNotSendToOtherServers)
+	return t.producer.SendEvents(t.context, []gomatrixserverlib.Event{e}, api.DoNotSendToOtherServers, nil)
 }
 
 func checkAllowedByState(e gomatrixserverlib.Event, stateEvents []gomatrixserverlib.Event) error {
diff --git a/src/github.com/matrix-org/dendrite/federationapi/routing/threepid.go b/src/github.com/matrix-org/dendrite/federationapi/routing/threepid.go
index cf261c45..6227d150 100644
--- a/src/github.com/matrix-org/dendrite/federationapi/routing/threepid.go
+++ b/src/github.com/matrix-org/dendrite/federationapi/routing/threepid.go
@@ -81,7 +81,7 @@ func CreateInvitesFrom3PIDInvites(
 	}
 
 	// Send all the events
-	if err := producer.SendEvents(req.Context(), evs, cfg.Matrix.ServerName); err != nil {
+	if err := producer.SendEvents(req.Context(), evs, cfg.Matrix.ServerName, nil); err != nil {
 		return httputil.LogThenError(req, err)
 	}
 
@@ -154,7 +154,7 @@ func ExchangeThirdPartyInvite(
 
 	// Send the event to the roomserver
 	if err = producer.SendEvents(
-		httpReq.Context(), []gomatrixserverlib.Event{signedEvent.Event}, cfg.Matrix.ServerName,
+		httpReq.Context(), []gomatrixserverlib.Event{signedEvent.Event}, cfg.Matrix.ServerName, nil,
 	); err != nil {
 		return httputil.LogThenError(httpReq, err)
 	}
diff --git a/src/github.com/matrix-org/dendrite/roomserver/api/input.go b/src/github.com/matrix-org/dendrite/roomserver/api/input.go
index fb4f7a61..504e751f 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/api/input.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/api/input.go
@@ -68,6 +68,16 @@ type InputRoomEvent struct {
 	// The server name to use to push this event to other servers.
 	// Or empty if this event shouldn't be pushed to other servers.
 	SendAsServer string `json:"send_as_server"`
+	// The transaction ID of the send request if sent by a local user and one
+	// was specified
+	TransactionID *TransactionID `json:"transaction_id"`
+}
+
+// TransactionID contains the transaction ID sent by a client when sending an
+// event, along with the ID of that device.
+type TransactionID struct {
+	DeviceID      string `json:"device_id"`
+	TransactionID string `json:"id"`
 }
 
 // InputInviteEvent is a matrix invite event received over federation without