persist entered custom backend url when navigating the site

src/components/form/BackendSelector.tsx

@@ -100,9 +100,26 @@ export function BackendSelector({
   showCustom = true,
 }: BackendSelectorProps) {
   const { t } = useTranslation();
-  const [customUrl, setCustomUrl] = useState("");
+  // Helper to strip protocol from URL for display
+  const stripProtocol = (url: string | null): string => {
+    if (!url) return "";
+    return url.replace(/^https?:\/\//, "");
+  };
+
+  // Initialize customUrl from selectedUrl if it's a custom URL (not in availableUrls)
+  const isCustomUrl = selectedUrl && !availableUrls.includes(selectedUrl);
+  const [customUrl, setCustomUrl] = useState(
+    isCustomUrl ? stripProtocol(selectedUrl) : "",
+  );
   const [backendOptions, setBackendOptions] = useState<BackendOption[]>([]);
 
+  // Update customUrl when selectedUrl changes and it's a custom URL
+  useEffect(() => {
+    if (selectedUrl && !availableUrls.includes(selectedUrl)) {
+      setCustomUrl(stripProtocol(selectedUrl));
+    }
+  }, [selectedUrl, availableUrls]);
+
   // Initialize and fetch meta for backend options
   useEffect(() => {
     const fetchMetas = async () => {
@@ -142,9 +159,7 @@ export function BackendSelector({
   };
 
   const isCustomUrlSelected =
-    customUrl &&
+    selectedUrl !== null && !availableUrls.includes(selectedUrl);
-    selectedUrl === customUrl &&
-    !availableUrls.includes(selectedUrl);
 
   return (
     <div className="space-y-4">

src/pages/Login.tsx

@@ -18,10 +18,6 @@ import { useAuthStore } from "@/stores/auth";
 export function LoginPage() {
   const navigate = useNavigate();
   const { t } = useTranslation();
-  const [showBackendSelection, setShowBackendSelection] = useState(true);
-  const [selectedBackendUrl, setSelectedBackendUrl] = useState<string | null>(
-    null,
-  );
   const setBackendUrl = useAuthStore((s) => s.setBackendUrl);
   const config = conf();
   const availableBackends =
@@ -37,6 +33,11 @@ export function LoginPage() {
     currentBackendUrl ??
     (availableBackends.length === 1 ? availableBackends[0] : null);
 
+  const [showBackendSelection, setShowBackendSelection] = useState(true);
+  const [selectedBackendUrl, setSelectedBackendUrl] = useState<string | null>(
+    currentBackendUrl ?? null,
+  );
+
   const handleBackendSelect = (url: string | null) => {
     setSelectedBackendUrl(url);
     if (url) {

src/pages/Register.tsx

@@ -38,14 +38,8 @@ function CaptchaProvider(props: {
 export function RegisterPage() {
   const navigate = useNavigate();
   const { t } = useTranslation();
-  const [step, setStep] = useState(-1);
-  const [mnemonic, setMnemonic] = useState<null | string>(null);
-  const [account, setAccount] = useState<null | AccountProfile>(null);
-  const [siteKey, setSiteKey] = useState<string | null>(null);
-  const [selectedBackendUrl, setSelectedBackendUrl] = useState<string | null>(
-    null,
-  );
   const setBackendUrl = useAuthStore((s) => s.setBackendUrl);
+  const currentBackendUrl = useAuthStore((s) => s.backendUrl);
   const config = conf();
   const availableBackends =
     config.BACKEND_URLS.length > 0
@@ -54,6 +48,14 @@ export function RegisterPage() {
         ? [config.BACKEND_URL]
         : [];
 
+  const [step, setStep] = useState(-1);
+  const [mnemonic, setMnemonic] = useState<null | string>(null);
+  const [account, setAccount] = useState<null | AccountProfile>(null);
+  const [siteKey, setSiteKey] = useState<string | null>(null);
+  const [selectedBackendUrl, setSelectedBackendUrl] = useState<string | null>(
+    currentBackendUrl ?? null,
+  );
+
   const handleBackendSelect = (url: string | null) => {
     setSelectedBackendUrl(url);
     if (url) {