diff --git a/example/reader_util.c b/example/reader_util.c
index 3c49563edb6..1ede37ca2f1 100644
--- a/example/reader_util.c
+++ b/example/reader_util.c
@@ -483,6 +483,8 @@ struct ndpi_workflow* ndpi_workflow_init(const struct ndpi_workflow_prefs * pref
   workflow->prefs       = *prefs;
   workflow->ndpi_struct = module;
 
+  ndpi_set_user_data(module, workflow);
+
   ndpi_set_log_level(module, nDPI_LogLevel);
 
   if(_debug_protocols != NULL && ! _debug_protocols_ok) {
diff --git a/src/include/ndpi_api.h b/src/include/ndpi_api.h
index 0a420accb4d..eac4bcd2544 100644
--- a/src/include/ndpi_api.h
+++ b/src/include/ndpi_api.h
@@ -1942,6 +1942,25 @@ extern "C" {
 				char *out, u_int out_len,
 				u_int8_t use_json);
 
+  /* ******************************* */
+
+  /**
+   * Set user data which can later retrieved with `ndpi_get_user_data()`.
+   *
+   * @par ndpi_str = the struct created for the protocol detection
+   * @par user_data = user data pointer you want to retrieve later with `ndpi_get_user_data()`
+   *
+   */
+  void ndpi_set_user_data(struct ndpi_detection_module_struct *ndpi_str, void *user_data);
+
+  /**
+   * Get user data which was previously set with `ndpi_set_user_data()`.
+   *
+   * @return the user data pointer
+   *
+   */
+  void *ndpi_get_user_data(struct ndpi_detection_module_struct *ndpi_str);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/include/ndpi_typedefs.h b/src/include/ndpi_typedefs.h
index d857899da33..1cc55047c33 100644
--- a/src/include/ndpi_typedefs.h
+++ b/src/include/ndpi_typedefs.h
@@ -221,8 +221,10 @@ typedef struct ndpi_protocol_bitmask_struct {
   ndpi_ndpi_mask fds_bits[NDPI_NUM_FDS_BITS];
 } ndpi_protocol_bitmask_struct_t;
 
+struct ndpi_detection_module_struct;
+
 /* NDPI_DEBUG_FUNCTION_PTR (cast) */
-typedef void (*ndpi_debug_function_ptr) (u_int32_t protocol, void *module_struct,
+typedef void (*ndpi_debug_function_ptr) (u_int32_t protocol, struct ndpi_detection_module_struct *module_struct,
 					 ndpi_log_level_t log_level, const char *file,
 					 const char *func, unsigned line,
 					 const char *format, ...);
@@ -1158,9 +1160,7 @@ struct ndpi_detection_module_struct {
   u_int8_t skip_tls_blocks_until_change_cipher:1, enable_ja3_plus:1, _notused:6;
   u_int8_t tls_certificate_expire_in_x_days;
   
-#ifdef NDPI_ENABLE_DEBUG_MESSAGES
   void *user_data;
-#endif
   char custom_category_labels[NUM_CUSTOM_CATEGORIES][CUSTOM_CATEGORY_LABEL_LEN];
 
   /* callback function buffer */
diff --git a/src/lib/ndpi_main.c b/src/lib/ndpi_main.c
index 7a5de852f2f..b37ae40ab6a 100644
--- a/src/lib/ndpi_main.c
+++ b/src/lib/ndpi_main.c
@@ -2863,9 +2863,7 @@ struct ndpi_detection_module_struct *ndpi_init_detection_module(ndpi_init_prefs
   ndpi_str->max_packets_to_process = NDPI_DEFAULT_MAX_NUM_PKTS_PER_FLOW_TO_DISSECT;
 
   NDPI_BITMASK_SET_ALL(ndpi_str->detection_bitmask);
-#ifdef NDPI_ENABLE_DEBUG_MESSAGES
   ndpi_str->user_data = NULL;
-#endif
 
   ndpi_str->tcp_max_retransmission_window_size = NDPI_DEFAULT_MAX_TCP_RETRANSMISSION_WINDOW_SIZE;
   ndpi_str->tls_certificate_expire_in_x_days = 30; /* NDPI_TLS_CERTIFICATE_ABOUT_TO_EXPIRE flow risk */
@@ -9801,3 +9799,20 @@ u_int32_t ndpi_get_protocol_aggressiveness(struct ndpi_detection_module_struct *
     return -1;
   }
 }
+
+/* ******************************************************************** */
+
+void ndpi_set_user_data(struct ndpi_detection_module_struct *ndpi_str, void *user_data)
+{
+  if (ndpi_str->user_data != NULL)
+  {
+    NDPI_LOG_ERR(ndpi_str, "%s", "User data is already set. Overwriting.")
+  }
+
+  ndpi_str->user_data = user_data;
+}
+
+void *ndpi_get_user_data(struct ndpi_detection_module_struct *ndpi_str)
+{
+  return ndpi_str->user_data;
+}