diff --git a/include/sdb/ht_inc.h b/include/sdb/ht_inc.h
index d019d210..67d146c9 100644
--- a/include/sdb/ht_inc.h
+++ b/include/sdb/ht_inc.h
@@ -39,7 +39,7 @@ extern "C" {
 #define KEY_TYPE ut64
 #define VALUE_TYPE ut64
 #define KEY_TO_HASH(x) ((ut32)(x))
-#define HT_NULL_VALUE 0
+#define HT_NULL_VALUE UT64_MAX
 #else
 #define HtName_(name) name##PU
 #define Ht_(name) ht_pu_##name
@@ -47,7 +47,7 @@ extern "C" {
 #define KEY_TYPE void *
 #define VALUE_TYPE ut64
 #define KEY_TO_HASH(x) ((ut32)(uintptr_t)(x))
-#define HT_NULL_VALUE 0
+#define HT_NULL_VALUE UT64_MAX
 #endif
 
 #include "ls.h"
diff --git a/src/ht.c b/src/ht.c
index 45fffc6f..ece07912 100644
--- a/src/ht.c
+++ b/src/ht.c
@@ -1,4 +1,4 @@
-/* sdb - MIT - Copyright 2011-2022 - pancake */
+/* sdb - MIT - Copyright 2011-2023 - pancake */
 
 #include "sdb/ht.h"
 
@@ -16,20 +16,24 @@ SDB_API HtPP* sdb_ht_new(void) {
 }
 
 static bool sdb_ht_internal_insert(HtPP* ht, const char* key, const char* value, bool update) {
-	if (!ht || !key || !*key || !value) {
+	if (!ht) { // should be an assert
 		return false;
 	}
 	SdbKv kvp = {{ 0 }};
-	kvp.base.key = sdb_strdup (key);
-	if (!kvp.base.key) {
-		goto err;
+	if (key) {
+		kvp.base.key = sdb_strdup (key);
+		if (!kvp.base.key) {
+			goto err;
+		}
+		kvp.base.key_len = strlen ((const char *)kvp.base.key);
 	}
-	kvp.base.value = sdb_strdup (value);
-	if (!kvp.base.value) {
-		goto err;
+	if (value) {
+		kvp.base.value = value? sdb_strdup (value): NULL;
+		if (!kvp.base.value) {
+			goto err;
+		}
+		kvp.base.value_len = strlen ((const char *)kvp.base.value);
 	}
-	kvp.base.key_len = strlen ((const char *)kvp.base.key);
-	kvp.base.value_len = strlen ((const char *)kvp.base.value);
 	kvp.expire = 0;
 	return ht_pp_insert_kv (ht, (HtPPKv*)&kvp, update);
 
diff --git a/src/ht_uu.c b/src/ht_uu.c
index 28e7d936..40cf16a8 100644
--- a/src/ht_uu.c
+++ b/src/ht_uu.c
@@ -1,4 +1,4 @@
-/* sdb - MIT - Copyright 2018-2022 - ret2libc, pancake */
+/* sdb - MIT - Copyright 2018-2023 - ret2libc, pancake */
 
 #include "sdb/sdb.h"
 #include "sdb/ht_uu.h"
diff --git a/test/unit/test_hash.c b/test/unit/test_hash.c
index f2a5e049..24c81641 100644
--- a/test/unit/test_hash.c
+++ b/test/unit/test_hash.c
@@ -11,10 +11,14 @@ typedef struct _test_struct {
 
 bool test_ht_insert_lookup(void) {
 	HtPP *ht = sdb_ht_new ();
+	sdb_ht_insert (ht, "NULL", NULL);
 	sdb_ht_insert (ht, "AAAA", "vAAAA");
 	sdb_ht_insert (ht, "BBBB", "vBBBB");
 	sdb_ht_insert (ht, "CCCC", "vCCCC");
 
+	mu_assert_eq (sdb_ht_exists (ht, "NULL"), 1, "NULL value wrong");
+	mu_assert_eq (sdb_ht_find (ht, "NULL", NULL), NULL, "NULL value wrong");
+	mu_assert_eq (sdb_ht_find (ht, "NONE", NULL), NULL, "NULL value wrong");
 	mu_assert_streq (sdb_ht_find (ht, "BBBB", NULL), "vBBBB", "BBBB value wrong");
 	mu_assert_streq (sdb_ht_find (ht, "AAAA", NULL), "vAAAA", "AAAA value wrong");
 	mu_assert_streq (sdb_ht_find (ht, "CCCC", NULL), "vCCCC", "CCCC value wrong");