diff --git a/src/middleware.ts b/src/middleware.ts
index dcd71b3..031d1e0 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -3,6 +3,10 @@ import { COURSES } from './config/courses';
 
 export const onRequest = defineMiddleware((ctx, next) => {
   const { pathname, searchParams } = ctx.url;
+  // legacy alias: the app's canonical domain is moodle.saillant.cc (SP4)
+  if (ctx.url.hostname === 'formations.saillant.cc') {
+    return ctx.redirect(`https://moodle.saillant.cc${pathname}${ctx.url.search}`, 301);
+  }
   if (pathname === '/course/view.php') {
     const id = Number(searchParams.get('id'));
     const course = COURSES.find((c) => c.id === id);