diff --git a/constants.php b/constants.php
index 871e258a5a11b776111fe46f2c56f31bcf9c3366..ce4b631aed92a208f9ee7e024f1a633d45b7eafe 100644
--- a/constants.php
+++ b/constants.php
@@ -6,8 +6,8 @@
 $versionString = '2.9.1';
 $rootDirNameToUseString = 'work';
 
-$isDebug = false; //logs debug to STDOUT
-$debugOutputAllReturnOutput = false; //if true && $isDebug every response is also written to STDOUT
+$isDebug = true; //logs debug (only if next line is true too)
+$debugOutputAllReturnOutput = false; //if true && $isDebug every response is also written to a file
 
 $s_testServerCode = 'testServerCode'; # the test server code for one test
 $s_testServerMessage = 'testServerMessage'; # the test server message for one test
@@ -176,10 +176,6 @@ function output($responseCode, $message, $data = null)
     global $s_timings_string_separator;
     global $debugTimings;
 
-    if ($isDebug && $debugOutputAllReturnOutput) {
-        fwrite(STDOUT, $message);
-    }
-
     $responseObj = array(
         'responseCode' => $responseCode,
         'message' => $message,
@@ -189,6 +185,12 @@ function output($responseCode, $message, $data = null)
 
     $responseString = json_encode($responseObj);
 
+    # make sure the file exist and is write/readable!
+    if ($isDebug && $debugOutputAllReturnOutput) {
+        #fwrite(STDOUT, $message);
+        file_put_contents('debugLogging.log', $responseString, FILE_APPEND);
+    }
+
     echo $responseString;
 }