diff --git a/backend/internal/http/router/handlers-web.go b/backend/internal/http/router/handlers-web.go
index 9b0bc1322..e76090112 100644
--- a/backend/internal/http/router/handlers-web.go
+++ b/backend/internal/http/router/handlers-web.go
@@ -134,6 +134,7 @@ func (e *Router) startSessionHandlerWeb(w http.ResponseWriter, r *http.Request)
 		UserUUID:        userUUID,
 		SessionID:       strconv.FormatUint(tokenData.ID, 10),
 		BeaconSizeLimit: e.cfg.BeaconSizeLimit,
+		StartTimestamp:  e.services.Flaker.ExtractTimestamp(tokenData.ID),
 	})
 }
 
diff --git a/backend/internal/http/router/model.go b/backend/internal/http/router/model.go
index b39c49688..bd9084e7b 100644
--- a/backend/internal/http/router/model.go
+++ b/backend/internal/http/router/model.go
@@ -16,6 +16,7 @@ type StartSessionRequest struct {
 
 type StartSessionResponse struct {
 	Timestamp       int64  `json:"timestamp"`
+	StartTimestamp  int64  `json:"startTimestamp"`
 	Delay           int64  `json:"delay"`
 	Token           string `json:"token"`
 	UserUUID        string `json:"userUUID"`