diff --git a/src/modules/http/src/httpJson.c b/src/modules/http/src/httpJson.c
index cb036d71c9ba73d4d68c886b811731af597360c2..7e503f89c3d8576d962c839ef8627afea8b0ff64 100644
--- a/src/modules/http/src/httpJson.c
+++ b/src/modules/http/src/httpJson.c
@@ -240,11 +240,11 @@ void httpJsonTimestamp(JsonBuf* buf, int64_t t) {
   struct tm* ptm;
   time_t     tt = t / 1000;
   ptm = localtime(&tt);
-  int length = (int)strftime(ts, 30, "%Y-%m-%d %H:%M:%S", ptm);
+  int length = (int)strftime(ts, 30, "%Y-%m-%dT%H:%M:%S", ptm);
 
-  snprintf(ts+length, MAX_NUM_STR_SZ, ".%03ld", t % 1000);
+  snprintf(ts+length, MAX_NUM_STR_SZ, ".%03ldZ", t % 1000);
 
-  httpJsonString(buf, ts, length + 4);
+  httpJsonString(buf, ts, length + 5);
 }
 
 void httpJsonInt(JsonBuf* buf, int num) {
@@ -396,4 +396,4 @@ void httpJsonPairStatus(JsonBuf* buf, int code) {
         httpJsonPair(buf, "desc", 4, tsError[code], (int)strlen(tsError[code]));
     }
   }
-}
\ No newline at end of file
+}