diff --git a/src/http/response/randval.c b/src/http/response/randval.c
index ef2994d..03bdf87 100644
--- a/src/http/response/randval.c
+++ b/src/http/response/randval.c
@@ -33,7 +33,7 @@
 #include "http/message.h"
 #include "http/header.h"
 
-#define RESP_DATA "{\"ctime\":%ld,\"vnext\":%ld,\"value\":%02d}"
+#define RESP_DATA "{\"ctime\":%ld,\"vnext\":%ld,\"value\":\"%02d\"}"
 
 HttpResponse
 httpResponseRandval(time_t ctime, int value)