diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 5a7a9872a..518ed3147 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -181,4 +181,12 @@ module ApplicationHelper
   def show_outdated_browser_banner?
     !supported_browser? && !has_dismissed_outdated_browser_banner?
   end
+
+  def vite_legacy?
+    if ENV['VITE_LEGACY'] == 'disabled'
+      false
+    else
+      Rails.env.production? || ENV['VITE_LEGACY'] == 'enabled'
+    end
+  end
 end
diff --git a/app/views/layouts/application.html.haml b/app/views/layouts/application.html.haml
index 53d9160f4..e7507be09 100644
--- a/app/views/layouts/application.html.haml
+++ b/app/views/layouts/application.html.haml
@@ -43,7 +43,8 @@
       - if content_for?(:footer)
         = content_for(:footer)
 
-      = vite_legacy_javascript_tag 'application'
+      - if vite_legacy?
+        = vite_legacy_javascript_tag 'application'
 
       = yield :charts_js
 
diff --git a/config/env.example.optional b/config/env.example.optional
index 6260df964..e37733a8b 100644
--- a/config/env.example.optional
+++ b/config/env.example.optional
@@ -133,3 +133,7 @@ SENDINBLUE_BALANCING_VALUE="50"
 DOLIST_BALANCING_VALUE="50"
 # Used only by a migration to choose your default regarding procedure archive dossiers after duree_conservation_dossiers_dans_ds
 # DEFAULT_PROCEDURE_EXPIRES_WHEN_TERMINE_ENABLED=true
+
+# Enable vite legacy build (IE11). Legacy build is used in production (except if set to "disabled").
+# You might want to enable it in other environements for testing. Build time will be greatly impacted.
+VITE_LEGACY=""
diff --git a/vite.config.ts b/vite.config.ts
index 635ebe782..c1eefb422 100644
--- a/vite.config.ts
+++ b/vite.config.ts
@@ -4,27 +4,17 @@ import ViteLegacy from '@vitejs/plugin-legacy';
 import FullReload from 'vite-plugin-full-reload';
 import RubyPlugin from 'vite-plugin-ruby';
 
-export default defineConfig({
-  resolve: { alias: { '@utils': '/shared/utils.ts' } },
-  build: {
-    sourcemap: true,
-    rollupOptions: {
-      output: {
-        manualChunks(id) {
-          if (id.match('maplibre') || id.match('mapbox')) {
-            return 'maplibre';
-          }
-        }
-      }
-    }
-  },
-  plugins: [
-    RubyPlugin(),
-    ViteReact({
-      parserPlugins: ['classProperties', 'classPrivateProperties'],
-      jsxRuntime: 'classic'
-    }),
-    FullReload(['config/routes.rb', 'app/views/**/*'], { delay: 200 }),
+const plugins = [
+  RubyPlugin(),
+  ViteReact({
+    parserPlugins: ['classProperties', 'classPrivateProperties'],
+    jsxRuntime: 'classic'
+  }),
+  FullReload(['config/routes.rb', 'app/views/**/*'], { delay: 200 })
+];
+
+if (shouldBuildLegacy()) {
+  plugins.push(
     ViteLegacy({
       targets: [
         'defaults',
@@ -48,5 +38,32 @@ export default defineConfig({
         'yet-another-abortcontroller-polyfill'
       ]
     })
-  ]
+  );
+}
+
+export default defineConfig({
+  resolve: { alias: { '@utils': '/shared/utils.ts' } },
+  build: {
+    sourcemap: true,
+    rollupOptions: {
+      output: {
+        manualChunks(id) {
+          if (id.match('maplibre') || id.match('mapbox')) {
+            return 'maplibre';
+          }
+        }
+      }
+    }
+  },
+  plugins
 });
+
+function shouldBuildLegacy() {
+  if (process.env.VITE_LEGACY == 'disabled') {
+    return false;
+  }
+  return (
+    process.env.RAILS_ENV == 'production' ||
+    process.env.VITE_LEGACY == 'enabled'
+  );
+}