diff --git a/app/game-frontend/test/viteConfig.test.ts b/app/game-frontend/test/viteConfig.test.ts
new file mode 100644
index 0000000..01a8abe
--- /dev/null
+++ b/app/game-frontend/test/viteConfig.test.ts
@@ -0,0 +1,15 @@
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import { mergeViteEnv } from '../vite.config.ts';
+
+void describe('game frontend Vite config', () => {
+    void it('prefers managed runtime values over values loaded from env files', () => {
+        const env = mergeViteEnv(
+            { VITE_APP_BASE_PATH: '/gateway', VITE_GAME_API_URL: '/gateway/api/trpc' },
+            { VITE_APP_BASE_PATH: '/hwe', VITE_GAME_API_URL: '/hwe/api/trpc' }
+        );
+
+        assert.equal(env.VITE_APP_BASE_PATH, '/hwe');
+        assert.equal(env.VITE_GAME_API_URL, '/hwe/api/trpc');
+    });
+});
diff --git a/app/game-frontend/vite.config.ts b/app/game-frontend/vite.config.ts
index d69ed51..96f4243 100644
--- a/app/game-frontend/vite.config.ts
+++ b/app/game-frontend/vite.config.ts
@@ -23,9 +23,17 @@ const resolvePreviewAllowedHosts = (value: string | undefined): true | string[]
     return hosts;
 };
 
+export const mergeViteEnv = (
+    fileEnv: Record<string, string>,
+    runtimeEnv: NodeJS.ProcessEnv
+): Record<string, string | undefined> => ({
+    ...fileEnv,
+    ...runtimeEnv,
+});
+
 // https://vitejs.dev/config/
 export default defineConfig(({ mode }) => {
-    const env = loadEnv(mode, process.cwd(), '');
+    const env = mergeViteEnv(loadEnv(mode, process.cwd(), ''), process.env);
     return {
         base: normalizeBasePath(env.VITE_APP_BASE_PATH),
         plugins: [vue(), tailwindcss()],