diff --git a/src/plugins/relay/api/relay-api-msg.c b/src/plugins/relay/api/relay-api-msg.c
index 67c7ef4c4..87dbae875 100644
--- a/src/plugins/relay/api/relay-api-msg.c
+++ b/src/plugins/relay/api/relay-api-msg.c
@@ -74,14 +74,13 @@
     ptr_string = weechat_hdata_string (hdata, pointer, __var_name);     \
     MSG_ADD_STR_PTR(__json_name, ptr_string);
 
-#define MSG_ADD_HDATA_STR_COLORS(__json_name, __var_name)               \
-    ptr_string = weechat_hdata_string (hdata, pointer, __var_name);     \
+#define MSG_CONVERT_COLORS(__json_name, __string)                       \
     switch (colors)                                                     \
     {                                                                   \
         case RELAY_API_COLORS_ANSI:                                     \
             string = weechat_hook_modifier_exec (                       \
                 "color_encode_ansi", NULL,                              \
-                (ptr_string) ? ptr_string : "");                        \
+                (__string) ? __string : "");                            \
             if (string)                                                 \
             {                                                           \
                 MSG_ADD_STR_PTR(__json_name, string);                   \
@@ -89,11 +88,11 @@
             }                                                           \
             break;                                                      \
         case RELAY_API_COLORS_WEECHAT:                                  \
-            MSG_ADD_STR_PTR(__json_name, ptr_string);                   \
+            MSG_ADD_STR_PTR(__json_name, __string);                     \
             break;                                                      \
         case RELAY_API_COLORS_STRIP:                                    \
             string = weechat_string_remove_color (                      \
-                (ptr_string) ? ptr_string : "", NULL);                  \
+                (__string) ? __string : "", NULL);                      \
             if (string)                                                 \
             {                                                           \
                 MSG_ADD_STR_PTR(__json_name, string);                   \
@@ -103,6 +102,16 @@
             break;                                                      \
     }
 
+#define MSG_ADD_HDATA_STR_COLORS(__json_name, __var_name)               \
+    ptr_string = weechat_hdata_string (hdata, pointer, __var_name);     \
+    MSG_CONVERT_COLORS(__json_name, ptr_string);
+
+#define MSG_ADD_HDATA_COLOR(__json_name, __var_name)                    \
+    ptr_string = weechat_hdata_string (hdata, pointer, __var_name);     \
+    ptr_color = (ptr_string && ptr_string[0]) ?                         \
+        weechat_color (ptr_string) : NULL;                              \
+    MSG_CONVERT_COLORS(__json_name, ptr_color);
+
 
 /*
  * Sends JSON response to client (internal use).
@@ -415,7 +424,8 @@ relay_api_msg_buffer_to_json (struct t_gui_buffer *buffer,
     if (nicks)
     {
         json_nicklist = relay_api_msg_nick_group_to_json (
-            weechat_hdata_pointer (hdata, buffer, "nicklist_root"));
+            weechat_hdata_pointer (hdata, buffer, "nicklist_root"),
+            colors);
         if (json_nicklist)
             cJSON_AddItemToObject (json, "nicklist", json_nicklist);
     }
@@ -553,13 +563,15 @@ relay_api_msg_lines_to_json (struct t_gui_buffer *buffer,
  */
 
 cJSON *
-relay_api_msg_nick_to_json (struct t_gui_nick *nick)
+relay_api_msg_nick_to_json (struct t_gui_nick *nick,
+                            enum t_relay_api_colors colors)
 {
     struct t_hdata *hdata;
     struct t_gui_nick *pointer;
     struct t_gui_nick_group *ptr_group;
     cJSON *json;
-    const char *ptr_string;
+    const char *ptr_string, *ptr_color;
+    char *string;
 
     hdata = relay_hdata_nick;
     pointer = nick;
@@ -579,9 +591,9 @@ relay_api_msg_nick_to_json (struct t_gui_nick *nick)
             (ptr_group) ?
             weechat_hdata_longlong (relay_hdata_nick_group, ptr_group, "id") : -1));
     MSG_ADD_HDATA_STR("prefix", "prefix");
-    MSG_ADD_HDATA_STR("prefix_color", "prefix_color");
+    MSG_ADD_HDATA_COLOR("prefix_color", "prefix_color");
     MSG_ADD_HDATA_STR("name", "name");
-    MSG_ADD_HDATA_STR("color", "color");
+    MSG_ADD_HDATA_COLOR("color", "color");
     MSG_ADD_HDATA_VAR(Bool, "visible", integer, "visible");
 
     return json;
@@ -592,13 +604,15 @@ relay_api_msg_nick_to_json (struct t_gui_nick *nick)
  */
 
 cJSON *
-relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group)
+relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group,
+                                  enum t_relay_api_colors colors)
 {
     struct t_hdata *hdata;
     struct t_gui_nick_group *pointer, *ptr_group;
     struct t_gui_nick *ptr_nick;
     cJSON *json, *json_groups, *json_nicks;
-    const char *ptr_string;
+    const char *ptr_string, *ptr_color;
+    char *string;
 
     hdata = relay_hdata_nick_group;
     pointer = nick_group;
@@ -618,7 +632,7 @@ relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group)
             (ptr_group) ?
             weechat_hdata_longlong (relay_hdata_nick_group, ptr_group, "id") : -1));
     MSG_ADD_HDATA_STR("name", "name");
-    MSG_ADD_HDATA_STR("color", "color");
+    MSG_ADD_HDATA_COLOR("color", "color");
     MSG_ADD_HDATA_VAR(Bool, "visible", integer, "visible");
 
     json_groups = cJSON_CreateArray ();
@@ -631,7 +645,7 @@ relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group)
             {
                 cJSON_AddItemToArray (
                     json_groups,
-                    relay_api_msg_nick_group_to_json (ptr_group));
+                    relay_api_msg_nick_group_to_json (ptr_group, colors));
                 ptr_group = weechat_hdata_move (relay_hdata_nick_group, ptr_group, 1);
             }
         }
@@ -648,7 +662,7 @@ relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group)
             {
                 cJSON_AddItemToArray (
                     json_nicks,
-                    relay_api_msg_nick_to_json (ptr_nick));
+                    relay_api_msg_nick_to_json (ptr_nick, colors));
                 ptr_nick = weechat_hdata_move (relay_hdata_nick, ptr_nick, 1);
             }
         }
diff --git a/src/plugins/relay/api/relay-api-msg.h b/src/plugins/relay/api/relay-api-msg.h
index 686918865..16516b4f4 100644
--- a/src/plugins/relay/api/relay-api-msg.h
+++ b/src/plugins/relay/api/relay-api-msg.h
@@ -46,8 +46,10 @@ extern cJSON *relay_api_msg_lines_to_json (struct t_gui_buffer *pointer,
                                            enum t_relay_api_colors colors);
 extern cJSON *relay_api_msg_line_data_to_json (struct t_gui_line_data *line_data,
                                                enum t_relay_api_colors colors);
-extern cJSON *relay_api_msg_nick_to_json (struct t_gui_nick *nick);
-extern cJSON *relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group);
+extern cJSON *relay_api_msg_nick_to_json (struct t_gui_nick *nick,
+                                          enum t_relay_api_colors colors);
+extern cJSON *relay_api_msg_nick_group_to_json (struct t_gui_nick_group *nick_group,
+                                                enum t_relay_api_colors colors);
 extern cJSON *relay_api_msg_hotlist_to_json (struct t_gui_hotlist *hotlist);
 
 #endif /* WEECHAT_PLUGIN_RELAY_API_MSG_H */
diff --git a/src/plugins/relay/api/relay-api-protocol.c b/src/plugins/relay/api/relay-api-protocol.c
index 031fc0144..fbb0ed2a5 100644
--- a/src/plugins/relay/api/relay-api-protocol.c
+++ b/src/plugins/relay/api/relay-api-protocol.c
@@ -171,7 +171,9 @@ relay_api_protocol_hsignal_nicklist_cb (const void *pointer, void *data,
         || (strcmp (signal, "nicklist_group_changed") == 0)
         || (strcmp (signal, "nicklist_group_removing") == 0))
     {
-        json = relay_api_msg_nick_group_to_json (ptr_group);
+        json = relay_api_msg_nick_group_to_json (
+            ptr_group,
+            RELAY_API_DATA(ptr_client, sync_colors));
         if (json)
         {
             relay_api_msg_send_event (ptr_client, signal, ptr_buffer,
@@ -183,7 +185,9 @@ relay_api_protocol_hsignal_nicklist_cb (const void *pointer, void *data,
         || (strcmp (signal, "nicklist_nick_changed") == 0)
         || (strcmp (signal, "nicklist_nick_removing") == 0))
     {
-        json = relay_api_msg_nick_to_json (ptr_nick);
+        json = relay_api_msg_nick_to_json (
+            ptr_nick,
+            RELAY_API_DATA(ptr_client, sync_colors));
         if (json)
         {
             relay_api_msg_send_event (ptr_client, signal, ptr_buffer,
@@ -409,7 +413,8 @@ RELAY_API_PROTOCOL_CALLBACK(buffers)
         {
             json = relay_api_msg_nick_group_to_json (
                 weechat_hdata_pointer (relay_hdata_buffer,
-                                       ptr_buffer, "nicklist_root"));
+                                       ptr_buffer, "nicklist_root"),
+                colors);
         }
         else
         {