diff --git a/appservice/http.go b/appservice/http.go
index 85b2893a..b280b299 100644
--- a/appservice/http.go
+++ b/appservice/http.go
@@ -295,6 +295,19 @@ func (as *AppService) PostPing(w http.ResponseWriter, r *http.Request) {
 	if !as.CheckServerToken(w, r) {
 		return
 	}
+	body, err := io.ReadAll(r.Body)
+	if err != nil || len(body) == 0 || !json.Valid(body) {
+		Error{
+			ErrorCode:  ErrNotJSON,
+			HTTPStatus: http.StatusBadRequest,
+			Message:    "Missing request body",
+		}.Write(w)
+		return
+	}
+
+	var txn mautrix.ReqAppservicePing
+	_ = json.Unmarshal(body, &txn)
+	as.Log.Debug().Str("txn_id", txn.TxnID).Msg("Received ping from homeserver")
 
 	w.Header().Add("Content-Type", "application/json")
 	w.WriteHeader(http.StatusOK)
diff --git a/bridge/bridge.go b/bridge/bridge.go
index 63f12e90..c9917e89 100644
--- a/bridge/bridge.go
+++ b/bridge/bridge.go
@@ -302,9 +302,10 @@ func (br *Bridge) ensureConnection() {
 		}
 
 		if br.SpecVersions.UnstableFeatures["fi.mau.msc2659"] && br.AS.Host.Port != 0 {
-			resp, err := br.Bot.AppservicePing()
+			txnID := br.Bot.TxnID()
+			resp, err := br.Bot.AppservicePing(br.Config.AppService.ID, txnID)
 			if err != nil {
-				evt := br.ZLog.WithLevel(zerolog.FatalLevel).Err(err)
+				evt := br.ZLog.WithLevel(zerolog.FatalLevel).Err(err).Str("txn_id", txnID)
 				var httpErr mautrix.HTTPError
 				if errors.As(err, &httpErr) && httpErr.RespError != nil {
 					if val, ok := httpErr.RespError.ExtraData["body"].(string); ok {
@@ -320,7 +321,10 @@ func (br *Bridge) ensureConnection() {
 				evt.Msg("Homeserver -> bridge connection is not working")
 				os.Exit(13)
 			}
-			br.ZLog.Debug().Int64("duration_ms", resp.DurationMS).Msg("Homeserver -> bridge connection works")
+			br.ZLog.Debug().
+				Str("txn_id", txnID).
+				Int64("duration_ms", resp.DurationMS).
+				Msg("Homeserver -> bridge connection works")
 		} else {
 			br.ZLog.Debug().Msg("Homeserver does not support checking status of homeserver -> bridge connection")
 		}
diff --git a/client.go b/client.go
index ed94b802..f6e8b2d1 100644
--- a/client.go
+++ b/client.go
@@ -1963,10 +1963,11 @@ func (cli *Client) BatchSend(roomID id.RoomID, req *ReqBatchSend) (resp *RespBat
 	return
 }
 
-func (cli *Client) AppservicePing() (resp *RespAppservicePing, err error) {
+func (cli *Client) AppservicePing(id, txnID string) (resp *RespAppservicePing, err error) {
 	_, err = cli.MakeFullRequest(FullRequest{
 		Method:       http.MethodPost,
-		URL:          cli.BuildClientURL("unstable", "fi.mau.msc2659", "appservice", "ping"),
+		URL:          cli.BuildClientURL("unstable", "fi.mau.msc2659", "appservice", id, "ping"),
+		RequestJSON:  &ReqAppservicePing{TxnID: txnID},
 		ResponseJSON: &resp,
 		// This endpoint intentionally returns 50x, so don't retry
 		MaxAttempts: 1,
diff --git a/requests.go b/requests.go
index dd8e1b66..8c7571de 100644
--- a/requests.go
+++ b/requests.go
@@ -392,6 +392,10 @@ func (req *ReqHierarchy) Query() map[string]string {
 	return query
 }
 
+type ReqAppservicePing struct {
+	TxnID string `json:"transaction_id,omitempty"`
+}
+
 type ReqBeeperMergeRoom struct {
 	NewRoom ReqCreateRoom `json:"create"`
 	Key     string        `json:"key"`