diff --git a/src/gst/gstpipewiredeviceprovider.c b/src/gst/gstpipewiredeviceprovider.c
index 3025c8475..899479cd3 100644
--- a/src/gst/gstpipewiredeviceprovider.c
+++ b/src/gst/gstpipewiredeviceprovider.c
@@ -302,7 +302,7 @@ on_core_info (void *data, const struct pw_core_info *info)
   if (info == NULL || info->props == NULL)
     return;
 
-  value = spa_dict_lookup (info->props, "monitors");
+  value = spa_dict_lookup (info->props, PW_KEY_CORE_MONITORS);
   if (value) {
     gchar **monitors = g_strsplit (value, ",", -1);
     gint i;
diff --git a/src/modules/spa/spa-monitor.c b/src/modules/spa/spa-monitor.c
index 16c794250..31bb57b64 100644
--- a/src/modules/spa/spa-monitor.c
+++ b/src/modules/spa/spa-monitor.c
@@ -241,11 +241,11 @@ static void update_monitor(struct pw_core *core, const char *name)
 	props = pw_core_get_properties(core);
 
 	if (props)
-		monitors = pw_properties_get(props, "monitors");
+		monitors = pw_properties_get(props, PW_KEY_CORE_MONITORS);
 	else
 		monitors = NULL;
 
-	item.key = "monitors";
+	item.key = PW_KEY_CORE_MONITORS;
 	if (monitors == NULL)
 		item.value = name;
 	else
diff --git a/src/pipewire/keys.h b/src/pipewire/keys.h
index 2b91d2e87..20c693e57 100644
--- a/src/pipewire/keys.h
+++ b/src/pipewire/keys.h
@@ -61,6 +61,8 @@ extern "C" {
 #define PW_KEY_SEC_GID			"pipewire.sec.gid"	/**< client gid, set by protocol*/
 #define PW_KEY_SEC_LABEL		"pipewire.sec.label"	/**< client security label, set by protocol*/
 
+#define PW_KEY_CORE_MONITORS		"core.monitors"		/**< the apis monitored by core. */
+
 /* remote keys */
 #define PW_KEY_REMOTE_NAME		"remote.name"		/**< The name of the remote to connect to,
 								  *  default env(PIPEWIRE_REMOTE) or pipewire-0 */