diff --git a/CMakeLists.txt b/CMakeLists.txt
index 32cbeebde7..06a21b1ce5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -510,7 +510,13 @@ option(CURL_DISABLE_TYPECHECK "Disable curl_easy_setopt()/curl_easy_getinfo() ty
 mark_as_advanced(CURL_DISABLE_TYPECHECK)
 option(CURL_DISABLE_VERBOSE_STRINGS "Disable verbose strings" OFF)
 mark_as_advanced(CURL_DISABLE_VERBOSE_STRINGS)
+option(CURL_DEBUG_GLOBAL_MEM "Debug curl_global_init_mem" OFF)
+mark_as_advanced(CURL_DEBUG_GLOBAL_MEM)
 
+if(CURL_DEBUG_GLOBAL_MEM)
+  # Set it via the command-line to make it apply to the entire directory.
+  set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS "CURL_DEBUG_GLOBAL_MEM")
+endif()
 if(CURL_DISABLE_TYPECHECK)
   # Set it via the command-line to make it apply to examples also.
   set_property(DIRECTORY APPEND PROPERTY COMPILE_DEFINITIONS "CURL_DISABLE_TYPECHECK")
diff --git a/configure.ac b/configure.ac
index 99ecbce5bc..9ae0cfd068 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1087,6 +1087,23 @@ AS_HELP_STRING([--disable-mqtt],[Disable MQTT support]),
     AC_MSG_RESULT(no)
 )
 
+AC_MSG_CHECKING([enable curl_global_init_mem debug build])
+AC_ARG_ENABLE(init-mem-debug,
+AS_HELP_STRING([--enable-init-mem-debug],[curl_global_init_mem debug])
+AS_HELP_STRING([--disable-init-mem-debug],[]),
+[ case "$enableval" in
+  yes)
+    AC_MSG_RESULT(yes)
+    AC_DEFINE(CURL_DEBUG_GLOBAL_MEM, 1, [curl_debug_global_mem debug build])
+    SUPPORT_FEATURES="$SUPPORT_FEATURES global-mem-debug"
+    ;;
+  *)
+    AC_MSG_RESULT(no)
+    ;;
+  esac ],
+    AC_MSG_RESULT(no)
+)
+
 dnl **********************************************************************
 dnl Check for built-in manual
 dnl **********************************************************************
diff --git a/src/tool_cfgable.c b/src/tool_cfgable.c
index 0d151af02e..381ca874d9 100644
--- a/src/tool_cfgable.c
+++ b/src/tool_cfgable.c
@@ -21,6 +21,7 @@
  * SPDX-License-Identifier: curl
  *
  ***************************************************************************/
+#include <stddef.h>
 #include "tool_setup.h"
 
 #include "tool_cfgable.h"
@@ -206,6 +207,90 @@ void config_free(struct OperationConfig *config)
   }
 }
 
+#ifdef CURL_DEBUG_GLOBAL_MEM
+
+#ifdef CURL_MEMDEBUG
+#error "curl_global_init_mem() testing does not work with memdebug debugging"
+#endif
+
+/*
+ * This is the custom memory functions handed to curl when we run special test
+ * round to verify them.
+ *
+ * The main point is to make sure that what is returned is different than what
+ * the regular memory functions return so that mixup will trigger problems.
+ */
+
+struct extramem {
+  size_t extra;
+  union {
+    curl_off_t o;
+    double d;
+    void *p;
+  } mem[1];
+};
+
+static void *custom_calloc(size_t wanted_nmemb, size_t wanted_size)
+{
+  struct extramem *m;
+  size_t sz = wanted_size * wanted_nmemb;
+  sz += sizeof(struct extramem);
+  m = curlx_calloc(1, sz);
+  if(m)
+    return m->mem;
+  return NULL;
+}
+
+static void *custom_malloc(size_t wanted_size)
+{
+  struct extramem *m;
+  size_t sz = wanted_size + sizeof(struct extramem);
+  m = curlx_malloc(sz);
+  if(m)
+    return m->mem;
+  return NULL;
+}
+
+static char *custom_strdup(const char *ptr)
+{
+  struct extramem *m;
+  size_t size = strlen(ptr) + 1;
+  size_t sz = size + sizeof(struct extramem);
+  m = curlx_malloc(sz);
+  if(m) {
+    char *p = (char *)m->mem;
+    /* since strcpy is banned, we do memcpy */
+    memcpy(p, ptr, sz);
+    p[sz] = 0;
+    return (char *)m->mem;
+  }
+  return NULL;
+
+}
+
+static void *custom_realloc(void *ptr, size_t size)
+{
+  struct extramem *m = NULL;
+  size_t sz = size + sizeof(struct extramem);
+  if(ptr)
+    m = (void *)((char *)ptr - offsetof(struct extramem, mem));
+  m = curlx_realloc(ptr, sz);
+  if(m)
+    return m->mem;
+  return NULL;
+}
+
+static void custom_free(void *ptr)
+{
+  struct extramem *m = NULL;
+  if(ptr) {
+    m = (void *)((char *)ptr - offsetof(struct extramem, mem));
+    curlx_free(m);
+  }
+}
+
+#endif
+
 /*
  * This is the main global constructor for the app. Call this before
  * _any_ libcurl usage. If this fails, *NO* libcurl functions may be
@@ -230,7 +315,13 @@ CURLcode globalconf_init(void)
   global->first = global->last = config_alloc();
   if(global->first) {
     /* Perform the libcurl initialization */
+#ifdef GLOBAL_MEM
+    result = curl_global_init_mem(CURL_GLOBAL_ALL, custom_malloc, custom_free,
+                                  custom_realloc, custom_strdup,
+                                  custom_calloc);
+#else
     result = curl_global_init(CURL_GLOBAL_DEFAULT);
+#endif
     if(!result) {
       /* Get information about libcurl */
       result = get_libcurl_info();