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");