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, "=&#");
diff --git a/include/openbmc_dbus_rest.hpp b/include/openbmc_dbus_rest.hpp
index c8673d1..73986b9 100644
--- a/include/openbmc_dbus_rest.hpp
+++ b/include/openbmc_dbus_rest.hpp
@@ -1071,7 +1071,7 @@
 int readVariantFromMessage(sdbusplus::message::message &m, nlohmann::json &data)
 {
     const char *containerType;
-    int r = sd_bus_message_peek_type(m.get(), NULL, &containerType);
+    int r = sd_bus_message_peek_type(m.get(), nullptr, &containerType);
     if (r < 0)
     {
         BMCWEB_LOG_ERROR << "sd_bus_message_peek_type failed";
diff --git a/include/pam_authenticate.hpp b/include/pam_authenticate.hpp
index 464f171..5d78efc 100644
--- a/include/pam_authenticate.hpp
+++ b/include/pam_authenticate.hpp
@@ -54,7 +54,7 @@
     std::string passStr(password);
     const struct pam_conv localConversation = {
         pamFunctionConversation, const_cast<char*>(passStr.c_str())};
-    pam_handle_t* localAuthHandle = NULL; // this gets set by pam_start
+    pam_handle_t* localAuthHandle = nullptr; // this gets set by pam_start
 
     if (pam_start("webserver", userStr.c_str(), &localConversation,
                   &localAuthHandle) != PAM_SUCCESS)
@@ -91,7 +91,7 @@
 {
     const struct pam_conv localConversation = {
         pamFunctionConversation, const_cast<char*>(password.c_str())};
-    pam_handle_t* localAuthHandle = NULL; // this gets set by pam_start
+    pam_handle_t* localAuthHandle = nullptr; // this gets set by pam_start
 
     int retval = pam_start("passwd", username.c_str(), &localConversation,
                            &localAuthHandle);
diff --git a/include/ssl_key_handler.hpp b/include/ssl_key_handler.hpp
index 2bd1f59..84aa097 100644
--- a/include/ssl_key_handler.hpp
+++ b/include/ssl_key_handler.hpp
@@ -56,7 +56,7 @@
         return false;
     }
 
-    int errCode = X509_STORE_CTX_init(storeCtx, x509Store, cert, NULL);
+    int errCode = X509_STORE_CTX_init(storeCtx, x509Store, cert, nullptr);
     if (errCode != 1)
     {
         BMCWEB_LOG_ERROR << "Error occured during X509_STORE_CTX_init call";
@@ -107,9 +107,9 @@
     std::cout << "Checking certs in file " << filepath << "\n";
 
     FILE *file = fopen(filepath.c_str(), "r");
-    if (file != NULL)
+    if (file != nullptr)
     {
-        EVP_PKEY *pkey = PEM_read_PrivateKey(file, NULL, NULL, NULL);
+        EVP_PKEY *pkey = PEM_read_PrivateKey(file, nullptr, nullptr, nullptr);
         if (pkey != nullptr)
         {
             RSA *rsa = EVP_PKEY_get1_RSA(pkey);
@@ -154,7 +154,7 @@
                 // key order issue.
                 fseek(file, 0, SEEK_SET);
 
-                X509 *x509 = PEM_read_X509(file, NULL, NULL, NULL);
+                X509 *x509 = PEM_read_X509(file, nullptr, nullptr, nullptr);
                 if (x509 == nullptr)
                 {
                     std::cout << "error getting x509 cert " << ERR_get_error()
@@ -176,7 +176,7 @@
 
 inline void generateSslCertificate(const std::string &filepath)
 {
-    FILE *pFile = NULL;
+    FILE *pFile = nullptr;
     std::cout << "Generating new keys\n";
     initOpenssl();
 
@@ -233,19 +233,19 @@
 
             if (pFile != nullptr)
             {
-                PEM_write_PrivateKey(pFile, pRsaPrivKey, NULL, NULL, 0, 0,
-                                     NULL);
+                PEM_write_PrivateKey(pFile, pRsaPrivKey, nullptr, nullptr, 0,
+                                     nullptr, nullptr);
 
                 PEM_write_X509(pFile, x509);
                 fclose(pFile);
-                pFile = NULL;
+                pFile = nullptr;
             }
 
             X509_free(x509);
         }
 
         EVP_PKEY_free(pRsaPrivKey);
-        pRsaPrivKey = NULL;
+        pRsaPrivKey = nullptr;
     }
 
     // cleanup_openssl();
@@ -253,7 +253,7 @@
 
 EVP_PKEY *createEcKey()
 {
-    EVP_PKEY *pKey = NULL;
+    EVP_PKEY *pKey = nullptr;
     int eccgrp = 0;
     eccgrp = OBJ_txt2nid("prime256v1");
 
diff --git a/redfish-core/lib/cpudimm.hpp b/redfish-core/lib/cpudimm.hpp
index d8d4191..ce36a0b 100644
--- a/redfish-core/lib/cpudimm.hpp
+++ b/redfish-core/lib/cpudimm.hpp
@@ -71,8 +71,8 @@
 {
     BMCWEB_LOG_DEBUG << "Get CPU resources by interface.";
 
-    const bool *present = NULL;
-    const bool *functional = NULL;
+    const bool *present = nullptr;
+    const bool *functional = nullptr;
     for (const auto &interface : cpuInterfacesProperties)
     {
         for (const auto &property : interface.second)
diff --git a/redfish-core/lib/log_services.hpp b/redfish-core/lib/log_services.hpp
index 643be9b..2eb00b6 100644
--- a/redfish-core/lib/log_services.hpp
+++ b/redfish-core/lib/log_services.hpp
@@ -190,7 +190,7 @@
         static_cast<time_t>(timestamp / 1000 / 1000); // Convert from us to s
     struct tm *loctime = localtime(&t);
     char entryTime[64] = {};
-    if (NULL != loctime)
+    if (nullptr != loctime)
     {
         strftime(entryTime, sizeof(entryTime), "%FT%T%z", loctime);
     }