diff --git a/common/src/interfaces/conversation.ts b/common/src/interfaces/conversation.ts
new file mode 100644
index 0000000..5fe2145
--- /dev/null
+++ b/common/src/interfaces/conversation.ts
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2022 Savoir-faire Linux Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License along with this program.  If not, see
+ * <https://www.gnu.org/licenses/>.
+ */
+import { IContact } from './contact';
+
+export interface IConversation {
+  id: string;
+  members: IConversationMember[];
+  messages: Message[];
+  infos: ConversationInfos;
+}
+
+export interface IConversationMember {
+  role?: ConversationMemberRole;
+  contact: IContact;
+}
+
+export type ConversationMemberRole = 'admin' | 'member' | 'invited' | 'banned' | 'left';
+
+export interface Message {
+  id: string;
+  author: string;
+  timestamp: string;
+  type:
+    | 'application/call-history+json'
+    | 'application/data-transfer+json'
+    | 'application/update-profile'
+    | 'initial'
+    | 'member'
+    | 'merge'
+    | 'text/plain'
+    | 'vote';
+  linearizedParent: string;
+  parents: string;
+  body?: string;
+  duration?: string;
+  to?: string;
+  invited?: string;
+}
+
+export interface ConversationInfos {
+  mode?: string;
+  title?: string;
+}
+
+export interface NewConversationRequestBody {
+  members: string[];
+}
+
+export interface NewMessageRequestBody {
+  message: string;
+}