diff --git a/config.json b/config.json
index 799586b..2962e47 100644
--- a/config.json
+++ b/config.json
@@ -17,6 +17,8 @@
 		"token": "SecretToken",
 		"iceServers": [
 			"stun:stun.l.google.com:19302"
-		]
+		],
+		"maxUsersPerCalls": 3,
+		"allowVideo": true
 	}
 }
\ No newline at end of file
diff --git a/src/controllers/ConversationsController.ts b/src/controllers/ConversationsController.ts
index 431abe4..7ba8e57 100644
--- a/src/controllers/ConversationsController.ts
+++ b/src/controllers/ConversationsController.ts
@@ -5,6 +5,7 @@ import { UserHelper } from "../helpers/UserHelper";
 import { removeHTMLNodes } from "../utils/StringUtils";
 import { ConversationMessage } from "../entities/ConversationMessage";
 import { UnreadConversation } from "../entities/UnreadConversation";
+import { CallsHelper } from "../helpers/CallsHelper";
 
 /**
  * Conversations controller
@@ -369,7 +370,8 @@ export class ConversationsController {
 			name: c.name.length > 0 ? c.name : false,
 			following: c.following ? 1 : 0,
 			saw_last_message: c.sawLastMessage ? 1 : 0,
-			members: [...c.members]
+			members: [...c.members],
+			can_have_call: CallsHelper.CanHaveCall(c)
 		};
 	}
 
diff --git a/src/controllers/RTCRelayController.ts b/src/controllers/RTCRelayController.ts
index c36ede3..497e235 100644
--- a/src/controllers/RTCRelayController.ts
+++ b/src/controllers/RTCRelayController.ts
@@ -73,6 +73,13 @@ export class RTCRelayController {
 		})
 	}
 
+	/**
+	 * Check out wheter a relay is currently connected to the API
+	 */
+	public static get IsConnected() : boolean {
+		return this.currWs && this.currWs.readyState == ws.OPEN;
+	}
+
 	/**
 	 * Method called when a websocket connection is closed
 	 */
diff --git a/src/helpers/CallsHelper.ts b/src/helpers/CallsHelper.ts
new file mode 100644
index 0000000..2af369b
--- /dev/null
+++ b/src/helpers/CallsHelper.ts
@@ -0,0 +1,24 @@
+/**
+ * Calls helper
+ * 
+ * @author Pierre Hubert
+ */
+
+import { Conversation } from "../entities/Conversation";
+import { conf } from "./ConfigHelper";
+import { RTCRelayController } from "../controllers/RTCRelayController";
+
+export class CallsHelper {
+
+	/**
+	 * Check out whether a given conversation can have a call or not
+	 * 
+	 * @param conv Target conversation
+	 */
+	public static CanHaveCall(conv: Conversation) : boolean {
+		return (conf().rtc_relay && RTCRelayController.IsConnected
+			&& conv.members.size > 1
+			&& conf().rtc_relay.maxUsersPerCalls >= conv.members.size) === true
+	}
+
+}
\ No newline at end of file
diff --git a/src/helpers/ConfigHelper.ts b/src/helpers/ConfigHelper.ts
index 0a91d51..06bdab4 100644
--- a/src/helpers/ConfigHelper.ts
+++ b/src/helpers/ConfigHelper.ts
@@ -18,7 +18,10 @@ export interface DatabaseConfiguration {
 export interface RTCRelayConfiguration {
 	ip ?: string,
 	token: string,
-	iceServers: string[]
+	iceServers: string[],
+
+	maxUsersPerCalls: number,
+	allowVideo: boolean,
 }
 
 export interface Configuration {