diff --git a/.clangd b/.clangd
index 2a1dc75..e343b1b 100644
--- a/.clangd
+++ b/.clangd
@@ -13,7 +13,7 @@ CompileFlags:
 If:
     PathMatch: [.*\.c, .*\.h]
 CompileFlags:
-    Add: [-std=gnu99]
+    Add: [-std=c99]
 
 
 ---
diff --git a/c/keyval.c b/c/keyval.c
index 23d99cb..0a17d06 100644
--- a/c/keyval.c
+++ b/c/keyval.c
@@ -2,6 +2,7 @@
 /* Copyright 2022 Ivan Polyakov */
 
 #include "keyval.h"
+#include "utils.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -57,8 +58,8 @@ int rpd_keyval_insert(rpd_keyval *keyval, const char *key, const char *value)
         keyval->size++;
     }
 
-    item->key = strdup(key);
-    item->val = strdup(value);
+    item->key = rpd_strdup(key);
+    item->val = rpd_strdup(value);
 
     return item->key && item->val ? 0 : 2;
 }
diff --git a/c/query.c b/c/query.c
index 1219e98..7515bd8 100644
--- a/c/query.c
+++ b/c/query.c
@@ -17,7 +17,7 @@ int rpd_query_parse(rpd_keyval *dest, const char *src)
         return 0;
     }
 
-    char *query = strdup(src);
+    char *query = rpd_strdup(src);
     if (!query)
         return 1;
 
@@ -28,7 +28,7 @@ int rpd_query_parse(rpd_keyval *dest, const char *src)
 
     char *tokens = query, *p = query;
     int i = 0;
-    while ((p = strsep(&tokens, "&\n")) && i < len) {
+    while ((p = rpd_strsep(&tokens, "&\n")) && i < len) {
         char *param, *val;
 
         if (*p == '=')
@@ -37,8 +37,8 @@ int rpd_query_parse(rpd_keyval *dest, const char *src)
         val = strtok(NULL, "=");
 
         if (param) {
-            dest->items[i].key = strdup(param);
-            dest->items[i].val = val ? strdup(val) : NULL;
+            dest->items[i].key = rpd_strdup(param);
+            dest->items[i].val = val ? rpd_strdup(val) : NULL;
             i++;
         }
     }
diff --git a/c/url.c b/c/url.c
index e7b5046..9cf99cf 100644
--- a/c/url.c
+++ b/c/url.c
@@ -23,11 +23,11 @@ int rpd_url_parse(rpd_url *dest, const char *src)
 
     i = 0;
     char *tmp, *token;
-    tmp = strdup(src);
-    while ((token = strsep(&tmp, "/"))) {
+    tmp = rpd_strdup(src);
+    while ((token = rpd_strsep(&tmp, "/"))) {
         if (!strlen(token))
             continue;
-        dest->parts[i] = strdup(token);
+        dest->parts[i] = rpd_strdup(token);
         i++;
     }
     free(tmp);
@@ -65,7 +65,7 @@ int rpd_url_params_parse_keys(rpd_keyval *dest, const rpd_url *tpl)
 
     for (int i = 0; i < tpl->parts_len; i++) {
         if (*tpl->parts[i] == ':') {
-            dest->items[dest->size].key = strdup(tpl->parts[i] + 1);
+            dest->items[dest->size].key = rpd_strdup(tpl->parts[i] + 1);
             dest->size++;
         }
     }
@@ -78,7 +78,7 @@ int rpd_url_params_parse_vals(rpd_keyval *dest, const rpd_url *url, const rpd_ur
     int i = 0, j = 0;
     while (i < tpl->parts_len) {
         if (*tpl->parts[i] == ':') {
-            dest->items[j++].val = strdup(url->parts[i]);
+            dest->items[j++].val = rpd_strdup(url->parts[i]);
         }
         i++;
     }
diff --git a/c/utils.c b/c/utils.c
index fb2762b..174ed2a 100644
--- a/c/utils.c
+++ b/c/utils.c
@@ -2,6 +2,8 @@
 /* Copyright 2022 Ivan Polyakov */
 
 #include "utils.h"
+#include <stdlib.h>
+#include <string.h>
 
 int count_char_entries(const char *str, char ch)
 {
@@ -14,3 +16,30 @@ int count_char_entries(const char *str, char ch)
     }
     return cnt;
 }
+
+char *rpd_strdup(const char *src)
+{
+    size_t size = strlen(src) + 1;
+    char *dest = (char *) malloc(sizeof(char) * size);
+    if (!dest) {
+        return NULL;
+    }
+    return memcpy(dest, src, size);
+}
+
+char *rpd_strsep(char **str, const char *sep)
+{
+    char *s = *str, *end;
+    if (!s) {
+        return NULL;
+    }
+
+    end = s + strcspn(s, sep);
+    if (*end) {
+        *end++ = 0;
+    } else {
+        end = 0;
+    }
+    *str = end;
+    return s;
+}
diff --git a/c/utils.h b/c/utils.h
index 2ca2d9c..53c6430 100644
--- a/c/utils.h
+++ b/c/utils.h
@@ -6,4 +6,8 @@
 
 int count_char_entries(const char *str, char ch);
 
+char *rpd_strdup(const char *src);
+
+char *rpd_strsep(char **str, const char *sep);
+
 #endif /* RAPIDA_UTILS_H_ENTRY */
diff --git a/config.mk b/config.mk
index c28750c..9f9c983 100644
--- a/config.mk
+++ b/config.mk
@@ -3,7 +3,7 @@ VERSION=0.2.2
 PREFIX=/usr/local
 
 CC=gcc
-CFLAGS=-std=gnu99 -pedantic -Iinclude
+CFLAGS=-std=c99 -pedantic -Iinclude
 CXX=c++
 CXXFLAGS=-pedantic -Iinclude
 CXXSTD=-ansi