diff --git a/apps/visualizer/vite.config.ts b/apps/visualizer/vite.config.ts
index 8c5fe11..6cbf362 100644
--- a/apps/visualizer/vite.config.ts
+++ b/apps/visualizer/vite.config.ts
@@ -9,6 +9,11 @@ const ROOT = path.resolve(DIR, '../..');
 
 type BasicAuth = { username: string; password: string };
 
+function stripTrailingSlashes(p: string): string {
+  const out = p.replace(/\/+$/, '');
+  return out || '/';
+}
+
 function readApiReadToken(): string | undefined {
   if (process.env.API_READ_TOKEN) return process.env.API_READ_TOKEN;
   const p = path.join(ROOT, 'tokens', 'read.json');
@@ -56,30 +61,98 @@ function readProxyBasicAuth(): BasicAuth | undefined {
 
 const apiReadToken = readApiReadToken();
 const proxyBasicAuth = readProxyBasicAuth();
+const apiProxyTarget = process.env.API_PROXY_TARGET || 'http://localhost:8787';
+
+function parseUrl(v: string): URL | undefined {
+  try {
+    return new URL(v);
+  } catch {
+    return undefined;
+  }
+}
+
+const apiProxyTargetUrl = parseUrl(apiProxyTarget);
+const apiProxyTargetPath = stripTrailingSlashes(apiProxyTargetUrl?.pathname || '/');
+const apiProxyTargetEndsWithApi = apiProxyTargetPath.endsWith('/api');
+
+function inferUiProxyTarget(apiTarget: string): string | undefined {
+  try {
+    const u = new URL(apiTarget);
+    const p = stripTrailingSlashes(u.pathname || '/');
+    if (!p.endsWith('/api')) return undefined;
+    const basePath = p.slice(0, -'/api'.length) || '/';
+    u.pathname = basePath;
+    u.search = '';
+    u.hash = '';
+    const out = u.toString();
+    return out.endsWith('/') ? out.slice(0, -1) : out;
+  } catch {
+    return undefined;
+  }
+}
+
+const uiProxyTarget =
+  process.env.FRONTEND_PROXY_TARGET ||
+  process.env.UI_PROXY_TARGET ||
+  process.env.AUTH_PROXY_TARGET ||
+  inferUiProxyTarget(apiProxyTarget) ||
+  (apiProxyTargetUrl && apiProxyTargetPath === '/' ? stripTrailingSlashes(apiProxyTargetUrl.toString()) : undefined);
+
+function applyProxyBasicAuth(proxyReq: any) {
+  if (!proxyBasicAuth) return false;
+  const b64 = Buffer.from(`${proxyBasicAuth.username}:${proxyBasicAuth.password}`, 'utf8').toString('base64');
+  proxyReq.setHeader('Authorization', `Basic ${b64}`);
+  return true;
+}
+
+function rewriteSetCookieForLocalDevHttp(proxyRes: any) {
+  const v = proxyRes?.headers?.['set-cookie'];
+  if (!v) return;
+  const rewrite = (cookie: string) => {
+    let out = cookie.replace(/;\s*secure\b/gi, '');
+    out = out.replace(/;\s*domain=[^;]+/gi, '');
+    out = out.replace(/;\s*samesite=none\b/gi, '; SameSite=Lax');
+    return out;
+  };
+  proxyRes.headers['set-cookie'] = Array.isArray(v) ? v.map(rewrite) : rewrite(String(v));
+}
+
+const proxy: Record<string, any> = {
+  '/api': {
+    target: apiProxyTarget,
+    changeOrigin: true,
+    rewrite: (p: string) => (apiProxyTargetEndsWithApi ? p.replace(/^\/api/, '') : p),
+    configure: (p: any) => {
+      p.on('proxyReq', (proxyReq: any) => {
+        if (applyProxyBasicAuth(proxyReq)) return;
+        if (apiReadToken) proxyReq.setHeader('Authorization', `Bearer ${apiReadToken}`);
+      });
+    },
+  },
+};
+
+if (uiProxyTarget) {
+  for (const prefix of ['/whoami', '/auth', '/logout']) {
+    proxy[prefix] = {
+      target: uiProxyTarget,
+      changeOrigin: true,
+      configure: (p: any) => {
+        p.on('proxyReq', (proxyReq: any) => {
+          applyProxyBasicAuth(proxyReq);
+        });
+        p.on('proxyRes', (proxyRes: any) => {
+          rewriteSetCookieForLocalDevHttp(proxyRes);
+        });
+      },
+    };
+  }
+}
 
 export default defineConfig({
   plugins: [react()],
   server: {
     port: 5173,
     strictPort: true,
-    proxy: {
-      '/api': {
-        target: process.env.API_PROXY_TARGET || 'http://localhost:8787',
-        changeOrigin: true,
-        rewrite: (p) => p.replace(/^\/api/, ''),
-        configure: (proxy) => {
-          proxy.on('proxyReq', (proxyReq) => {
-            if (proxyBasicAuth) {
-              const b64 = Buffer.from(`${proxyBasicAuth.username}:${proxyBasicAuth.password}`, 'utf8').toString(
-                'base64'
-              );
-              proxyReq.setHeader('Authorization', `Basic ${b64}`);
-              return;
-            }
-            if (apiReadToken) proxyReq.setHeader('Authorization', `Bearer ${apiReadToken}`);
-          });
-        },
-      },
-    },
+    proxy,
   },
 });