diff --git a/src/module.c b/src/module.c
index f24c0af2a..ff36a9f86 100644
--- a/src/module.c
+++ b/src/module.c
@@ -4374,9 +4374,9 @@ robj *moduleTypeDupOrReply(client *c, robj *fromkey, robj *tokey, robj *value) {
  *             .defrag = myType_DefragCallback
  *         }
  *
- * * **rdb_load**: A callback function pointer that loads data from RDB files.
- * * **rdb_save**: A callback function pointer that saves data to RDB files.
- * * **aof_rewrite**: A callback function pointer that rewrites data as commands.
+ * * **rdb_load**: A callback function pointer that loads data from RDB files. (mandatory)
+ * * **rdb_save**: A callback function pointer that saves data to RDB files. (mandatory)
+ * * **aof_rewrite**: A callback function pointer that rewrites data as commands. (mandatory)
  * * **digest**: A callback function pointer that is used for `DEBUG DIGEST`.
  * * **free**: A callback function pointer that can free a type value.
  * * **aux_save**: A callback function pointer that saves out of keyspace data to RDB files.
@@ -4416,8 +4416,8 @@ robj *moduleTypeDupOrReply(client *c, robj *fromkey, robj *tokey, robj *value) {
  * Note: the module name "AAAAAAAAA" is reserved and produces an error, it
  * happens to be pretty lame as well.
  *
- * If there is already a module registering a type with the same name,
- * and if the module name or encver is invalid, NULL is returned.
+ * If there is already a module registering a type with the same name, the name
+ * or encver are invalid, or a mandatory callback is missing, NULL is returned.
  * Otherwise the new type is registered into Redis, and a reference of
  * type RedisModuleType is returned: the caller of the function should store
  * this reference into a global variable to make future use of it in the
@@ -4460,6 +4460,16 @@ moduleType *RM_CreateDataType(RedisModuleCtx *ctx, const char *name, int encver,
         } v3;
     } *tms = (struct typemethods*) typemethods_ptr;
 
+    /* Persistence functions can't be NULL */
+    if (tms->rdb_load == NULL || tms->rdb_save == NULL || tms->aof_rewrite == NULL) {
+        return NULL;
+    }
+
+    /* Function aux_load and aux_save must be either both defined or undefined. */
+    if ((tms->version >= 2) && ((tms->v2.aux_load != NULL) != (tms->v2.aux_save != NULL))) {
+        return NULL;
+    }
+
     moduleType *mt = zcalloc(sizeof(*mt));
     mt->id = id;
     mt->module = ctx->module;
diff --git a/tests/modules/datatype.c b/tests/modules/datatype.c
index 0c6f95551..8c3ef2982 100644
--- a/tests/modules/datatype.c
+++ b/tests/modules/datatype.c
@@ -32,6 +32,10 @@ static void datatype_save(RedisModuleIO *io, void *value) {
     RedisModule_SaveString(io, dt->strval);
 }
 
+static void datatype_rewrite(RedisModuleIO *aof, RedisModuleString *key, void *value) {
+    /*  do-nothing callback. */
+}
+
 static void datatype_free(void *value) {
     if (value) {
         DataType *dt = (DataType *) value;
@@ -190,6 +194,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
         .version = REDISMODULE_TYPE_METHOD_VERSION,
         .rdb_load = datatype_load,
         .rdb_save = datatype_save,
+        .aof_rewrite = datatype_rewrite,
         .free = datatype_free,
         .copy = datatype_copy
     };
diff --git a/tests/modules/defragtest.c b/tests/modules/defragtest.c
index b63680c63..af11a905e 100644
--- a/tests/modules/defragtest.c
+++ b/tests/modules/defragtest.c
@@ -25,6 +25,20 @@ unsigned long int global_defragged = 0;
 int global_strings_len = 0;
 RedisModuleString **global_strings = NULL;
 
+static void *fragtype_load(RedisModuleIO *io, int encver) {
+    /*  do-nothing callback. */
+    return NULL;
+}
+
+static void fragtype_save(RedisModuleIO *io, void *value) {
+    /*  do-nothing callback. */
+}
+
+static void fragtype_rewrite(RedisModuleIO *aof, RedisModuleString *key, void *value) {
+    /*  do-nothing callback. */
+}
+
+
 static void createGlobalStrings(RedisModuleCtx *ctx, int count)
 {
     global_strings_len = count;
@@ -211,6 +225,9 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
 
     RedisModuleTypeMethods tm = {
             .version = REDISMODULE_TYPE_METHOD_VERSION,
+            .rdb_load = fragtype_load,
+            .rdb_save = fragtype_save,
+            .aof_rewrite = fragtype_rewrite,
             .free = FragFree,
             .free_effort = FragFreeEffort,
             .defrag = FragDefrag
diff --git a/tests/modules/testrdb.c b/tests/modules/testrdb.c
index 5d9382a3a..9f08f4f36 100644
--- a/tests/modules/testrdb.c
+++ b/tests/modules/testrdb.c
@@ -79,6 +79,11 @@ void testrdb_type_save(RedisModuleIO *rdb, void *value) {
     RedisModule_SaveLongDouble(rdb, 0.333333333333333333L);
 }
 
+
+void testrdb_type_aof_rewrite(RedisModuleIO *aof, RedisModuleString *key, void *value) {
+    /*  do-nothing callback. */
+}
+
 void testrdb_aux_save(RedisModuleIO *rdb, int when) {
     if (conf_aux_count==1) assert(when == REDISMODULE_AUX_AFTER_RDB);
     if (conf_aux_count==0) assert(0);
@@ -240,7 +245,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
             .version = 1,
             .rdb_load = testrdb_type_load,
             .rdb_save = testrdb_type_save,
-            .aof_rewrite = NULL,
+            .aof_rewrite = testrdb_type_aof_rewrite,
             .digest = NULL,
             .free = testrdb_type_free,
         };
@@ -253,7 +258,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
             .version = REDISMODULE_TYPE_METHOD_VERSION,
             .rdb_load = testrdb_type_load,
             .rdb_save = testrdb_type_save,
-            .aof_rewrite = NULL,
+            .aof_rewrite = testrdb_type_aof_rewrite,
             .digest = NULL,
             .free = testrdb_type_free,
             .aux_load = testrdb_aux_load,