diff --git a/src/components/CrewChat.tsx b/src/components/CrewChat.tsx
index 31ab37f..5806328 100644
--- a/src/components/CrewChat.tsx
+++ b/src/components/CrewChat.tsx
@@ -12,6 +12,8 @@ import { Badge } from '@/components/ui/badge';
 import { Skeleton } from '@/components/ui/skeleton';
 
 import { useCurrentUser } from '@/hooks/useCurrentUser';
+import { useNostrLogin } from '@nostrify/react/login';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 import { useAuthor } from '@/hooks/useAuthor';
 import { useToast } from '@/hooks/useToast';
 import {
@@ -112,6 +114,7 @@ export function CrewChat({
   canModerate = false,
 }: CrewChatProps) {
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { toast } = useToast();
   const [draft, setDraft] = useState('');
   const scrollRef = useRef<HTMLDivElement>(null);
@@ -165,7 +168,7 @@ export function CrewChat({
     }
   }, [messages]);
 
-  const canSendNip44 = !!user?.signer?.nip44;
+  const canSendNip44 = checkNip44(user, logins);
 
   const handleSend = async (e: React.FormEvent) => {
     e.preventDefault();
diff --git a/src/components/CrewRequestToJoin.tsx b/src/components/CrewRequestToJoin.tsx
index a4c7855..0d8dc36 100644
--- a/src/components/CrewRequestToJoin.tsx
+++ b/src/components/CrewRequestToJoin.tsx
@@ -11,8 +11,10 @@ import {
 import { Button } from '@/components/ui/button';
 import { Textarea } from '@/components/ui/textarea';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
+import { useNostrLogin } from '@nostrify/react/login';
 import { useSendDirectMessage } from '@/hooks/useDirectMessages';
 import { useToast } from '@/hooks/useToast';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 import { UserPlus, Loader2, Lock } from 'lucide-react';
 
 interface CrewRequestToJoinProps {
@@ -32,6 +34,7 @@ interface CrewRequestToJoinProps {
  */
 export function CrewRequestToJoin({ crewName, founderPubkey, admins = [] }: CrewRequestToJoinProps) {
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { mutateAsync: sendMessage, isPending } = useSendDirectMessage();
   const { toast } = useToast();
   const [open, setOpen] = useState(false);
@@ -46,7 +49,7 @@ export function CrewRequestToJoin({ crewName, founderPubkey, admins = [] }: Crew
   // Don't show for people already in the leadership.
   if (recipients.length === 0) return null;
 
-  const canDM = !!user.signer?.nip44;
+  const canDM = checkNip44(user, logins);
 
   const handleSend = async () => {
     if (!canDM) {
diff --git a/src/hooks/useDirectMessages.ts b/src/hooks/useDirectMessages.ts
index 621bd27..579d86b 100644
--- a/src/hooks/useDirectMessages.ts
+++ b/src/hooks/useDirectMessages.ts
@@ -4,8 +4,10 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { nip44, nip19, generateSecretKey, getPublicKey, finalizeEvent } from 'nostr-tools';
 
 import type { NostrEvent } from '@nostrify/nostrify';
+import { useNostrLogin } from '@nostrify/react/login';
 import { useCurrentUser } from './useCurrentUser';
 import { useAppContext } from './useAppContext';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 
 // NIP-17 Message Types
 export interface DirectMessage {
@@ -229,7 +231,9 @@ export function useSendTradeDM() {
 export function useConversation(otherPubkey: string) {
   const { nostr } = useNostr();
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { config } = useAppContext();
+  const nip44Available = checkNip44(user, logins);
 
   const relayUrls = config.relayMetadata.relays
     .filter(r => r.read)
@@ -326,7 +330,7 @@ export function useConversation(otherPubkey: string) {
       // Sort by creation time (oldest first for chat display)
       return messages.sort((a, b) => a.createdAt - b.createdAt);
     },
-    enabled: !!user?.signer?.nip44 && !!otherPubkey,
+    enabled: nip44Available && !!otherPubkey,
     staleTime: 30000,
     refetchInterval: 30000, // Poll for new messages
   });
@@ -338,7 +342,9 @@ export function useConversation(otherPubkey: string) {
 export function useConversations() {
   const { nostr } = useNostr();
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { config } = useAppContext();
+  const nip44Available = checkNip44(user, logins);
 
   const relayUrls = config.relayMetadata.relays
     .filter(r => r.read)
@@ -450,7 +456,7 @@ export function useConversations() {
         (b.lastMessage?.createdAt || 0) - (a.lastMessage?.createdAt || 0)
       );
     },
-    enabled: !!user?.signer?.nip44,
+    enabled: nip44Available,
     staleTime: 30000,
     refetchInterval: 60000, // Poll for new conversations
   });
@@ -475,7 +481,9 @@ export function formatPubkeyShort(pubkey: string): string {
 export function useGroupConversations() {
   const { nostr } = useNostr();
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { config } = useAppContext();
+  const nip44Available = checkNip44(user, logins);
 
   const relayUrls = config.relayMetadata.relays
     .filter(r => r.read)
@@ -598,7 +606,7 @@ export function useGroupConversations() {
         (b.lastMessage?.createdAt || 0) - (a.lastMessage?.createdAt || 0)
       );
     },
-    enabled: !!user?.signer?.nip44,
+    enabled: nip44Available,
     staleTime: 30000,
     refetchInterval: 60000,
   });
@@ -609,8 +617,10 @@ export function useGroupConversations() {
  */
 export function useGroupConversation(participants: string[]) {
   const { nostr } = useNostr();
+  const { logins } = useNostrLogin();
   const { user } = useCurrentUser();
   const { config } = useAppContext();
+  const nip44Available = checkNip44(user, logins);
   
   const groupId = getGroupId(participants);
 
@@ -702,7 +712,7 @@ export function useGroupConversation(participants: string[]) {
       // Sort by creation time (oldest first for chat display)
       return messages.sort((a, b) => a.createdAt - b.createdAt);
     },
-    enabled: !!user?.signer?.nip44 && participants.length > 0,
+    enabled: nip44Available && participants.length > 0,
     staleTime: 30000,
     refetchInterval: 30000,
   });
diff --git a/src/hooks/useStash.ts b/src/hooks/useStash.ts
index 532a2d0..5bb0884 100644
--- a/src/hooks/useStash.ts
+++ b/src/hooks/useStash.ts
@@ -4,6 +4,7 @@ import { useNostr } from '@nostrify/react';
 import { useNostrLogin } from '@nostrify/react/login';
 import { useCurrentUser } from './useCurrentUser';
 import { useNostrPublish } from './useNostrPublish';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 
 // Stash item stored in encrypted NIP-51 list
 export interface StashItem {
@@ -53,21 +54,7 @@ export function useStash() {
   const { mutateAsync: createEvent } = useNostrPublish();
 
   // Determine if nip44 is safely available WITHOUT touching any throwing getter.
-  // Extension signers throw "Browser extension not available" from their .nostr
-  // getter when window.nostr isn't present yet (page load race, or no extension).
-  // We check the login type instead: nsec and bunker have nip44 built-in always;
-  // extension logins only have it when window.nostr is present; amber never has it.
-  const hasNip44 = useMemo(() => {
-    if (!user?.pubkey) return false;
-    const login = logins.find((l) => l.pubkey === user.pubkey);
-    if (!login) return false;
-    // nsec and bunker: nip44 is always available (pure JS, no external dep)
-    if (login.type === 'nsec' || login.type === 'bunker') return true;
-    // extension: safe to check window.nostr directly (no getter, no throw)
-    if (login.type === 'extension') return !!(globalThis as { nostr?: { nip44?: unknown } }).nostr?.nip44;
-    // amber / unknown: no nip44 support
-    return false;
-  }, [user?.pubkey, logins]);
+  const hasNip44 = useMemo(() => checkNip44(user, logins), [user, logins]);
 
   // Fetch and decrypt stash
   const { data: stash, isLoading, error } = useQuery({
@@ -223,7 +210,7 @@ export function useStash() {
     addItem,
     updateItem,
     removeItem,
-    isEncryptionAvailable: !!user?.signer?.nip44,
+    isEncryptionAvailable: hasNip44,
   };
 }
 
diff --git a/src/lib/signerCapabilities.ts b/src/lib/signerCapabilities.ts
new file mode 100644
index 0000000..0647493
--- /dev/null
+++ b/src/lib/signerCapabilities.ts
@@ -0,0 +1,56 @@
+/**
+ * signerCapabilities — safely probe what a Nostr signer can do.
+ * ─────────────────────────────────────────────────────────────────────────────
+ * The NUser extension signer exposes `.nip44` / `.nip04` as GETTERS that call
+ * `.nostr` (window.nostr) and THROW "Browser extension not available" when the
+ * extension isn't present. Accessing `user.signer?.nip44` during render will
+ * therefore crash the whole React tree for extension logins whose extension
+ * isn't injected yet (page-load race) or is missing entirely.
+ *
+ * These helpers determine capability WITHOUT touching the throwing getter:
+ * we look at the login type + probe `window.nostr` directly (a plain property
+ * read that never throws). Use `hasNip44(user, logins)` anywhere you'd
+ * otherwise write `!!user?.signer?.nip44` in a render path.
+ */
+
+interface MaybeUser {
+  pubkey?: string;
+}
+
+interface MaybeLogin {
+  type: string;
+  pubkey?: string;
+}
+
+function windowNostr(): { nip44?: unknown; nip04?: unknown } | undefined {
+  return (globalThis as { nostr?: { nip44?: unknown; nip04?: unknown } }).nostr;
+}
+
+/** True if the user's signer can do NIP-44 encryption. Never throws. */
+export function hasNip44(
+  user: MaybeUser | null | undefined,
+  logins: readonly MaybeLogin[],
+): boolean {
+  if (!user?.pubkey) return false;
+  const login = logins.find((l) => l.pubkey === user.pubkey);
+  if (!login) return false;
+  // nsec + bunker: NIP-44 always available (pure JS / remote signer implements it)
+  if (login.type === 'nsec' || login.type === 'bunker') return true;
+  // extension: probe window.nostr directly (no throwing getter)
+  if (login.type === 'extension') return !!windowNostr()?.nip44;
+  // amber / unknown: no NIP-44
+  return false;
+}
+
+/** True if the user's signer can do NIP-04 encryption. Never throws. */
+export function hasNip04(
+  user: MaybeUser | null | undefined,
+  logins: readonly MaybeLogin[],
+): boolean {
+  if (!user?.pubkey) return false;
+  const login = logins.find((l) => l.pubkey === user.pubkey);
+  if (!login) return false;
+  if (login.type === 'nsec' || login.type === 'bunker') return true;
+  if (login.type === 'extension') return !!windowNostr()?.nip04;
+  return false;
+}
diff --git a/src/pages/ContactsPage.tsx b/src/pages/ContactsPage.tsx
index 7882e3a..ac5c0b7 100644
--- a/src/pages/ContactsPage.tsx
+++ b/src/pages/ContactsPage.tsx
@@ -11,6 +11,8 @@ import { Tabs, TabsList, TabsTrigger, TabsContent } from '@/components/ui/tabs';
 import { LoginArea } from '@/components/auth/LoginArea';
 import { ZapButton } from '@/components/ZapButton';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
+import { useNostrLogin } from '@nostrify/react/login';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 import { useAuthor } from '@/hooks/useAuthor';
 import { useFollowing } from '@/hooks/useFollowing';
 import { useConversations } from '@/hooks/useDirectMessages';
@@ -119,6 +121,7 @@ export default function ContactsPage() {
   });
 
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { toast } = useToast();
   const [query, setQuery] = useState('');
 
@@ -132,7 +135,7 @@ export default function ContactsPage() {
   const [pendingPubkey, setPendingPubkey] = useState<string | null>(null);
 
   const toggleSave = async (pubkey: string) => {
-    if (!user?.signer?.nip44) {
+    if (!checkNip44(user, logins)) {
       toast({
         title: 'Encryption unavailable',
         description: 'Your signer does not support NIP-44 encryption.',
diff --git a/src/pages/ConversationPage.tsx b/src/pages/ConversationPage.tsx
index 38a0997..84d1039 100644
--- a/src/pages/ConversationPage.tsx
+++ b/src/pages/ConversationPage.tsx
@@ -9,6 +9,8 @@ import { Textarea } from '@/components/ui/textarea';
 import { Avatar, AvatarImage, AvatarFallback } from '@/components/ui/avatar';
 import { Skeleton } from '@/components/ui/skeleton';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
+import { useNostrLogin } from '@nostrify/react/login';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 import { useConversation, useSendDirectMessage, type DirectMessage } from '@/hooks/useDirectMessages';
 import { useAuthor } from '@/hooks/useAuthor';
 import { genUserName } from '@/lib/genUserName';
@@ -66,6 +68,7 @@ export default function ConversationPage() {
   const { npub } = useParams<{ npub: string }>();
   const [searchParams] = useSearchParams();
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const messagesEndRef = useRef<HTMLDivElement>(null);
   
   // Support pre-filled message from URL query param
@@ -151,7 +154,7 @@ export default function ConversationPage() {
   }
 
   // Check NIP-44 support
-  if (!user.signer?.nip44) {
+  if (!checkNip44(user, logins)) {
     const isAndroid = /Android/i.test(navigator.userAgent);
     const isMobile = isAndroid || /iPhone|iPad|iPod/i.test(navigator.userAgent);
     
diff --git a/src/pages/DirectMessagesPage.tsx b/src/pages/DirectMessagesPage.tsx
index 076098a..a650dee 100644
--- a/src/pages/DirectMessagesPage.tsx
+++ b/src/pages/DirectMessagesPage.tsx
@@ -17,6 +17,8 @@ import {
   DialogDescription,
 } from '@/components/ui/dialog';
 import { useCurrentUser } from '@/hooks/useCurrentUser';
+import { useNostrLogin } from '@nostrify/react/login';
+import { hasNip44 as checkNip44 } from '@/lib/signerCapabilities';
 import { useConversations, formatPubkeyShort } from '@/hooks/useDirectMessages';
 import { useAuthor } from '@/hooks/useAuthor';
 import { genUserName } from '@/lib/genUserName';
@@ -135,6 +137,7 @@ function ConversationSkeleton() {
 
 export default function DirectMessagesPage() {
   const { user } = useCurrentUser();
+  const { logins } = useNostrLogin();
   const { data: conversations, isLoading, error } = useConversations();
   const [showNewMessage, setShowNewMessage] = useState(false);
   const [newRecipient, setNewRecipient] = useState('');
@@ -190,7 +193,7 @@ export default function DirectMessagesPage() {
   }
 
   // Check if NIP-44 is available
-  if (!user.signer?.nip44) {
+  if (!checkNip44(user, logins)) {
     const isAndroid = /Android/i.test(navigator.userAgent);
     const isIOS = /iPhone|iPad|iPod/i.test(navigator.userAgent);
     const isMobile = isAndroid || isIOS;