diff --git a/include/main.h b/include/main.h
index c8db846..b12c73c 100644
--- a/include/main.h
+++ b/include/main.h
@@ -26,6 +26,7 @@ uint8_t channel_gpio_by_idx(int idx);
 uint8_t channel_idx_by_gpio(int gpio);
 void channel_set(int idx, bool state);
 bool channel_get(int idx);
+int channel_get_total();
 void channel_report(int idx, char *msg, int msg_len);
 void channel_handler(int gpio, void *arg);
 
diff --git a/src/channel.c b/src/channel.c
index 013d4dd..a9e6042 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -13,6 +13,10 @@ static bool valid_gpio(const int gpio) {
   return true;
 }
 
+int channel_get_total() {
+  return s_num_channels;
+}
+
 bool channel_init(const char *fn) {
   char *json;
   void *h = NULL;
@@ -120,7 +124,7 @@ uint8_t channel_gpio_by_idx(int idx) {
 uint8_t channel_idx_by_gpio(int gpio) {
   uint8_t i;
 
-  for(i=0; i<3; i++) {
+  for(i=0; i<channel_get_total(); i++) {
     if (gpio == s_channels[i].button_gpio)
       return i;
   }
@@ -131,7 +135,7 @@ void channel_report(int idx, char *msg, int msg_len) {
   if (!msg || msg_len==0)
     return;
 
-  if (idx<0 || idx>=s_num_channels)
+  if (idx<0 || idx>=channel_get_total())
     return;
 
   snprintf(msg, msg_len-1, "{\"idx\": %d, \"button_gpio\": %d, \"led_gpio\": %d, \"relay_gpio\": %d, \"relay_state\": %d}",
@@ -141,7 +145,7 @@ void channel_report(int idx, char *msg, int msg_len) {
 void channel_set(int idx, bool state) {
   double now = mg_time();
 
-  if (idx<0 || idx>=s_num_channels)
+  if (idx<0 || idx>=channel_get_total())
     return;
 
   s_channels[idx].button_last_change = now;
@@ -153,7 +157,7 @@ void channel_set(int idx, bool state) {
 }
 
 bool channel_get(int idx) {
-  if (idx<0 || idx>=s_num_channels)
+  if (idx<0 || idx>=channel_get_total())
     return false;
 
   return s_channels[idx].relay_state == 1;
diff --git a/src/rpc.c b/src/rpc.c
index 9608534..7550d6e 100644
--- a/src/rpc.c
+++ b/src/rpc.c
@@ -21,8 +21,8 @@ static bool rpc_args_to_idx_and_gpio(struct mg_rpc_request_info *ri, struct mg_s
     return false;
   }
 
-  if (idx<0 || idx>2) {
-    mg_rpc_send_errorf(ri, 400, "idx must be 0, 1, 2");
+  if (idx<0 || idx>=channel_get_total()) {
+    mg_rpc_send_errorf(ri, 400, "idx must be between 0 and %d", channel_get_total()-1);
     ri = NULL;
     return false;
   }
@@ -95,8 +95,8 @@ static void rpc_channel_set_handler(struct mg_rpc_request_info *ri, void *cb_arg
     return;
   }
 
-  if (idx<0 || idx>2) {
-    mg_rpc_send_errorf(ri, 400, "idx must be 0, 1, 2");
+  if (idx<0 || idx>=channel_get_total()) {
+    mg_rpc_send_errorf(ri, 400, "idx must be between 0 and %d", channel_get_total()-1);
     ri = NULL;
     return;
   }