diff --git a/constants.cc b/constants.cc
index 767dc47..7f9fdf4 100644
--- a/constants.cc
+++ b/constants.cc
@@ -30,6 +30,8 @@
 const char kPrefsCurrentResponseSignature[] = "current-response-signature";
 const char kPrefsCurrentUrlFailureCount[] = "current-url-failure-count";
 const char kPrefsCurrentUrlIndex[] = "current-url-index";
+const char kPrefsDailyMetricsLastReportedAt[] =
+    "daily-metrics-last-reported-at";
 const char kPrefsDeltaUpdateFailures[] = "delta-update-failures";
 const char kPrefsFullPayloadAttemptNumber[] = "full-payload-attempt-number";
 const char kPrefsLastActivePingDay[] = "last-active-ping-day";