diff --git a/src/data/Contact.ts b/src/data/Contact.ts
index f96cf07..2ee9a90 100644
--- a/src/data/Contact.ts
+++ b/src/data/Contact.ts
@@ -1,9 +1,9 @@
 import { Mission } from "./Mission";
 
-export type Contact = {
+export type Contact = Readonly<{
   notionId: string;
   notionIdFamille: string;
   Nom: string;
   Missions: Mission[];
   AExercéUneMission: boolean;
-};
+}>;
diff --git a/src/data/Mission.ts b/src/data/Mission.ts
index 13d5024..07d1c9e 100644
--- a/src/data/Mission.ts
+++ b/src/data/Mission.ts
@@ -1,6 +1,6 @@
-export type Mission = {
+export type Mission = Readonly<{
   notionId: string;
   Nom: string;
   Equipe: string;
   ContactsNotionIds: string[];
-};
+}>;