diff --git a/http/http_server.h b/http/http_server.h
index 82ba9d0..df42214 100644
--- a/http/http_server.h
+++ b/http/http_server.h
@@ -95,7 +95,7 @@
 
     void updateDateStr()
     {
-        time_t lastTimeT = time(0);
+        time_t lastTimeT = time(nullptr);
         tm myTm{};
 
         gmtime_r(&lastTimeT, &myTm);
diff --git a/http/logging.h b/http/logging.h
index a608f1f..eb04cc1 100644
--- a/http/logging.h
+++ b/http/logging.h
@@ -27,7 +27,7 @@
     {
         std::string date;
         date.resize(32, '\0');
-        time_t t = time(0);
+        time_t t = time(nullptr);
 
         tm myTm{};
 
diff --git a/http/query_string.h b/http/query_string.h
index 959eb68..10753ac 100644
--- a/http/query_string.h
+++ b/http/query_string.h
@@ -138,7 +138,7 @@
 
     for (i = 0; i < qs_kv_size; i++)
     {
-        qs_kv[i] = NULL;
+        qs_kv[i] = nullptr;
     }
 
     // find the beginning of the k/v substrings or the fragment
@@ -255,7 +255,7 @@
     }
 #endif // _qsSORTING
 
-    return NULL;
+    return nullptr;
 }
 
 inline char* qsScanvalue(const char* key, const char* qs, char* val,
@@ -265,7 +265,7 @@
     const char* tmp;
 
     // find the beginning of the k/v substrings
-    if ((tmp = strchr(qs, '?')) != NULL)
+    if ((tmp = strchr(qs, '?')) != nullptr)
     {
         qs = tmp + 1;
     }
@@ -282,7 +282,7 @@
 
     if (qs[0] == '\0')
     {
-        return NULL;
+        return nullptr;
     }
 
     qs += strcspn(qs, "=&#");