diff --git a/config.json b/config.json
index 276c819..b6a4144 100644
--- a/config.json
+++ b/config.json
@@ -7,5 +7,13 @@
 		"dbName": "comunic",
 		"user": "pierre",
 		"password": "pierre"
+	},
+
+	"proxy": null,
+	"force_clients_https": null,
+
+	"rtc_relay": {
+		"ip": "127.0.0.1",
+		"token": "SecretToken"
 	}
 }
\ No newline at end of file
diff --git a/src/helpers/ConfigHelper.ts b/src/helpers/ConfigHelper.ts
index 41e54bd..0184523 100644
--- a/src/helpers/ConfigHelper.ts
+++ b/src/helpers/ConfigHelper.ts
@@ -15,13 +15,31 @@ export interface DatabaseConfiguration {
 	dbPrefix : string
 }
 
+export interface RTCRelayConfiguration {
+	ip ?: string,
+	token: string,
+}
+
 export interface Configuration {
+	
+	// Server listening port
 	port: number,
+
+	// Access to user data
 	storageURL : string,
 	storagePath : string,
+
+	// Database connection configuration
 	database : DatabaseConfiguration,
+
+	// URL of trusted proxy (to get remote IP address)
 	proxy ?: string,
-	force_clients_https ?: boolean
+
+	// Set access-control-allow-origin to require HTTPS
+	force_clients_https ?: boolean,
+
+	// RTC (for calls) proxy configuration
+	rtc_relay ?: RTCRelayConfiguration,
 }
 
 export class ConfigurationHelper {