diff --git a/esp32_device/.vscode/settings.json b/esp32_device/.vscode/settings.json
index 0bf7131..bef44a6 100644
--- a/esp32_device/.vscode/settings.json
+++ b/esp32_device/.vscode/settings.json
@@ -50,6 +50,9 @@
     "stdlib.h": "c",
     "secure_api.h": "c",
     "jwt.h": "c",
-    "sync_response.h": "c"
+    "sync_response.h": "c",
+    "gpio.h": "c",
+    "esp_system.h": "c",
+    "relays.h": "c"
   }
 }
diff --git a/esp32_device/main/CMakeLists.txt b/esp32_device/main/CMakeLists.txt
index a7b6504..882b510 100755
--- a/esp32_device/main/CMakeLists.txt
+++ b/esp32_device/main/CMakeLists.txt
@@ -1,4 +1,4 @@
-idf_component_register(SRCS "sync_response.c" "jwt.c" "secure_api.c" "http_client.c" "ethernet.c" "unsecure_api.c" "system.c" "crypto.c" "random.c" "storage.c" "main.c"
+idf_component_register(SRCS "relays.c" "sync_response.c" "jwt.c" "secure_api.c" "http_client.c" "ethernet.c" "unsecure_api.c" "system.c" "crypto.c" "random.c" "storage.c" "main.c"
                         "dev_name.c"
                     INCLUDE_DIRS ".")
 
diff --git a/esp32_device/main/constants.h b/esp32_device/main/constants.h
index eb0f81a..7f8375a 100644
--- a/esp32_device/main/constants.h
+++ b/esp32_device/main/constants.h
@@ -13,7 +13,7 @@
 /**
  * Device max number of relays
  */
-#define DEV_MAX_RELAYS 1
+#define DEV_MAX_RELAYS 5
 
 /**
  * Backend unsecure API URL
diff --git a/esp32_device/main/main.c b/esp32_device/main/main.c
index d1f89d4..65c867f 100755
--- a/esp32_device/main/main.c
+++ b/esp32_device/main/main.c
@@ -10,6 +10,7 @@
 #include "secure_api.h"
 #include "ethernet.h"
 #include "constants.h"
+#include "relays.h"
 
 static const char *TAG = "main";
 
@@ -21,7 +22,8 @@ void app_main(void)
 
     ESP_LOGI(TAG, "SolarEnergy WT32-ETH01 device");
 
-    // TODO : turn off all relays
+    // Turn off all relays
+    relays_turn_off_all();
 
     // Initialize storage
     if (storage_init() == false)
@@ -182,7 +184,7 @@ void app_main(void)
             if (fails > 5)
             {
                 ESP_LOGE(TAG, "Many failures, will stop all relays...");
-                // TODO : turn off all relays
+                relays_turn_off_all();
             }
 
             // Restart the card after too much failures
@@ -199,9 +201,13 @@ void app_main(void)
 
         fails = 0;
 
-        // TODO : apply sync
         sync_response_print(res);
 
+        for (size_t i = 0; i < DEV_MAX_RELAYS; i++)
+        {
+            relays_set(i, sync_response_is_relay_on(res, i));
+        }
+
         sync_response_free(res);
         system_sleep(SYNC_TIME_INTERVAL);
     }
diff --git a/esp32_device/main/relays.c b/esp32_device/main/relays.c
new file mode 100644
index 0000000..4aba4c3
--- /dev/null
+++ b/esp32_device/main/relays.c
@@ -0,0 +1,28 @@
+#include <driver/gpio.h>
+#include "esp_log.h"
+
+#include "relays.h"
+#include "constants.h"
+
+static const char *TAG = "relays";
+
+/**
+ * Device relays GPIO ids
+ */
+static int DEVICE_GPIO_IDS[5] = {2, 4, 12, 14, 15};
+
+void relays_turn_off_all()
+{
+    ESP_LOGI(TAG, "Turning off all relays...");
+
+    for (size_t i = 0; i < DEV_MAX_RELAYS; i++)
+    {
+        relays_set(i, false);
+    }
+}
+
+void relays_set(int number, bool is_on)
+{
+    size_t gpio_id = DEVICE_GPIO_IDS[number];
+    ESP_LOGI(TAG, "Set relay %d (gpio %d) to %s", number, gpio_id, is_on ? "on" : "off");
+}
\ No newline at end of file
diff --git a/esp32_device/main/relays.h b/esp32_device/main/relays.h
new file mode 100644
index 0000000..f1a5a50
--- /dev/null
+++ b/esp32_device/main/relays.h
@@ -0,0 +1,26 @@
+/**
+ * Relays management
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+    /**
+     * Turn off all relays
+     */
+    void relays_turn_off_all();
+
+    /**
+     * Turn on / off a relay
+     */
+    void relays_set(int number, bool is_on);
+
+#ifdef __cplusplus
+}
+#endif
diff --git a/esp32_device/main/sync_response.c b/esp32_device/main/sync_response.c
index 7ba3690..e8cf56e 100644
--- a/esp32_device/main/sync_response.c
+++ b/esp32_device/main/sync_response.c
@@ -51,6 +51,7 @@ sync_response *sync_response_parse(cJSON *res)
 void sync_response_print(sync_response *res)
 {
     ESP_LOGI(TAG, " === sync response begin === ");
+    ESP_LOGI(TAG, "# of relays: %d", res->len);
     for (size_t i = 0; i < res->len; i++)
         ESP_LOGI(TAG, "Relay[%d]=%s", i, res->relays[i] ? "ON" : "off");
     ESP_LOGI(TAG, " === sync response end === ");
@@ -60,4 +61,15 @@ void sync_response_free(sync_response *res)
 {
     if (res != NULL)
         free(res);
+}
+
+bool sync_response_is_relay_on(sync_response *res, int relay_number)
+{
+    if (res->len <= relay_number)
+    {
+        ESP_LOGW(TAG, "Requested state of an unconfigured relay (%d). Defaulting to off.", relay_number);
+        return false;
+    }
+
+    return res->relays[relay_number];
 }
\ No newline at end of file
diff --git a/esp32_device/main/sync_response.h b/esp32_device/main/sync_response.h
index b4a81db..828e074 100644
--- a/esp32_device/main/sync_response.h
+++ b/esp32_device/main/sync_response.h
@@ -34,6 +34,11 @@ extern "C"
      */
     void sync_response_free(sync_response *res);
 
+    /**
+     * Check the desired status of a relay
+     */
+    bool sync_response_is_relay_on(sync_response *res, int relay_number);
+
 #ifdef __cplusplus
 }
 #endif