diff --git a/client-app/app/(app)/chats/[id].tsx b/client-app/app/(app)/chats/[id].tsx
index c8fec3b..518cd48 100644
--- a/client-app/app/(app)/chats/[id].tsx
+++ b/client-app/app/(app)/chats/[id].tsx
@@ -26,7 +26,7 @@ import { encryptMessage } from '@/lib/crypto';
 import { sendEnvelope } from '@/lib/api';
 import { getWSClient } from '@/lib/ws';
 import { appendMessage, loadMessages } from '@/lib/storage';
-import { randomId } from '@/lib/utils';
+import { randomId, safeBack } from '@/lib/utils';
 import type { Message } from '@/lib/types';
 
 import { Avatar }        from '@/components/Avatar';
@@ -404,7 +404,7 @@ export default function ChatScreen() {
         ) : (
           <Header
             divider
-            left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+            left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
             title={
               <Pressable
                 onPress={onOpenPeerProfile}
diff --git a/client-app/app/(app)/compose.tsx b/client-app/app/(app)/compose.tsx
index e3ca43a..b7f8e53 100644
--- a/client-app/app/(app)/compose.tsx
+++ b/client-app/app/(app)/compose.tsx
@@ -37,6 +37,7 @@ import { useStore } from '@/lib/store';
 import { Avatar } from '@/components/Avatar';
 import { publishAndCommit, formatFee } from '@/lib/feed';
 import { humanizeTxError, getBalance } from '@/lib/api';
+import { safeBack } from '@/lib/utils';
 
 const MAX_CONTENT_LENGTH = 4000;
 const MAX_POST_BYTES     = 256 * 1024;   // must match server's MaxPostSize
@@ -212,7 +213,7 @@ export default function ComposeScreen() {
           borderBottomColor: '#141414',
         }}
       >
-        <Pressable onPress={() => router.back()} hitSlop={8}>
+        <Pressable onPress={() => safeBack()} hitSlop={8}>
           <Ionicons name="close" size={26} color="#ffffff" />
         </Pressable>
         <View style={{ flex: 1 }} />
diff --git a/client-app/app/(app)/feed/[id].tsx b/client-app/app/(app)/feed/[id].tsx
index 46fb1af..3ab9f59 100644
--- a/client-app/app/(app)/feed/[id].tsx
+++ b/client-app/app/(app)/feed/[id].tsx
@@ -31,6 +31,7 @@ import {
   fetchPost, fetchStats, bumpView, formatCount, formatFee,
   type FeedPostItem, type PostStats,
 } from '@/lib/feed';
+import { safeBack } from '@/lib/utils';
 
 export default function PostDetailScreen() {
   const insets = useSafeAreaInsets();
@@ -71,14 +72,14 @@ export default function PostDetailScreen() {
 
   const onDeleted = useCallback(() => {
     // Go back to feed — the post is gone.
-    router.back();
+    safeBack();
   }, []);
 
   return (
     <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
       <Header
         divider
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
         title="Post"
       />
 
diff --git a/client-app/app/(app)/feed/tag/[tag].tsx b/client-app/app/(app)/feed/tag/[tag].tsx
index fb8b42a..8e9bc6b 100644
--- a/client-app/app/(app)/feed/tag/[tag].tsx
+++ b/client-app/app/(app)/feed/tag/[tag].tsx
@@ -17,6 +17,7 @@ import { IconButton } from '@/components/IconButton';
 import { PostCard, PostSeparator } from '@/components/feed/PostCard';
 import { useStore } from '@/lib/store';
 import { fetchHashtag, fetchStats, type FeedPostItem } from '@/lib/feed';
+import { safeBack } from '@/lib/utils';
 
 export default function HashtagScreen() {
   const insets = useSafeAreaInsets();
@@ -80,7 +81,7 @@ export default function HashtagScreen() {
     <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
       <Header
         divider
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
         title={`#${tag}`}
       />
 
diff --git a/client-app/app/(app)/new-contact.tsx b/client-app/app/(app)/new-contact.tsx
index ca73657..d2b88f4 100644
--- a/client-app/app/(app)/new-contact.tsx
+++ b/client-app/app/(app)/new-contact.tsx
@@ -18,7 +18,7 @@ import { useSafeAreaInsets } from 'react-native-safe-area-context';
 import { useStore } from '@/lib/store';
 import { getIdentity, buildContactRequestTx, submitTx, resolveUsername, humanizeTxError } from '@/lib/api';
 import { shortAddr } from '@/lib/crypto';
-import { formatAmount } from '@/lib/utils';
+import { formatAmount, safeBack } from '@/lib/utils';
 
 import { Avatar } from '@/components/Avatar';
 import { Header } from '@/components/Header';
@@ -64,9 +64,20 @@ export default function NewContactScreen() {
         if (!addr) { setError(`@${name} is not registered on this chain`); return; }
         address = addr;
       }
+      // Block self-lookup — can't message yourself, and the on-chain
+      // CONTACT_REQUEST tx would go through but serve no purpose.
+      if (keyFile && address.toLowerCase() === keyFile.pub_key.toLowerCase()) {
+        setError("That's you. You can't send a contact request to yourself.");
+        return;
+      }
       const identity = await getIdentity(address);
+      const resolvedAddr = identity?.pub_key ?? address;
+      if (keyFile && resolvedAddr.toLowerCase() === keyFile.pub_key.toLowerCase()) {
+        setError("That's you. You can't send a contact request to yourself.");
+        return;
+      }
       setResolved({
-        address:  identity?.pub_key ?? address,
+        address:  resolvedAddr,
         nickname: identity?.nickname || undefined,
         x25519:   identity?.x25519_pub || undefined,
       });
@@ -79,6 +90,10 @@ export default function NewContactScreen() {
 
   async function sendRequest() {
     if (!resolved || !keyFile) return;
+    if (resolved.address.toLowerCase() === keyFile.pub_key.toLowerCase()) {
+      Alert.alert('Can\'t message yourself', "This is your own address.");
+      return;
+    }
     if (balance < fee + 1000) {
       Alert.alert('Insufficient balance', `Need ${formatAmount(fee + 1000)} (request fee + network).`);
       return;
@@ -96,7 +111,7 @@ export default function NewContactScreen() {
       Alert.alert(
         'Request sent',
         `A contact request has been sent to ${resolved.nickname ? '@' + resolved.nickname : shortAddr(resolved.address)}.`,
-        [{ text: 'OK', onPress: () => router.back() }],
+        [{ text: 'OK', onPress: () => safeBack() }],
       );
     } catch (e: any) {
       setError(humanizeTxError(e));
@@ -114,7 +129,7 @@ export default function NewContactScreen() {
       <Header
         title="Search"
         divider={false}
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
       />
       <ScrollView
         contentContainerStyle={{ padding: 14, paddingBottom: 120 }}
diff --git a/client-app/app/(app)/profile/[address].tsx b/client-app/app/(app)/profile/[address].tsx
index 1b4e634..a2f86b3 100644
--- a/client-app/app/(app)/profile/[address].tsx
+++ b/client-app/app/(app)/profile/[address].tsx
@@ -28,6 +28,7 @@ import { Header } from '@/components/Header';
 import { IconButton } from '@/components/IconButton';
 import { followUser, unfollowUser } from '@/lib/feed';
 import { humanizeTxError } from '@/lib/api';
+import { safeBack } from '@/lib/utils';
 
 function shortAddr(a: string, n = 10): string {
   if (!a) return '—';
@@ -87,7 +88,7 @@ export default function ProfileScreen() {
       <Header
         title="Profile"
         divider
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
       />
 
       <ScrollView contentContainerStyle={{ padding: 14, paddingBottom: insets.bottom + 30 }}>
diff --git a/client-app/app/(app)/settings.tsx b/client-app/app/(app)/settings.tsx
index 854fb2d..8414a9c 100644
--- a/client-app/app/(app)/settings.tsx
+++ b/client-app/app/(app)/settings.tsx
@@ -32,7 +32,7 @@ import {
   humanizeTxError,
 } from '@/lib/api';
 import { shortAddr } from '@/lib/crypto';
-import { formatAmount } from '@/lib/utils';
+import { formatAmount, safeBack } from '@/lib/utils';
 
 import { Avatar } from '@/components/Avatar';
 import { Header } from '@/components/Header';
@@ -335,7 +335,7 @@ export default function SettingsScreen() {
       <Header
         title="Settings"
         divider={false}
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack()} />}
       />
       <ScrollView
         contentContainerStyle={{ paddingBottom: 120 }}
diff --git a/client-app/app/(auth)/create.tsx b/client-app/app/(auth)/create.tsx
index 21c9d5e..5300783 100644
--- a/client-app/app/(auth)/create.tsx
+++ b/client-app/app/(auth)/create.tsx
@@ -10,6 +10,7 @@ import { useSafeAreaInsets } from 'react-native-safe-area-context';
 import { generateKeyFile } from '@/lib/crypto';
 import { saveKeyFile } from '@/lib/storage';
 import { useStore } from '@/lib/store';
+import { safeBack } from '@/lib/utils';
 
 import { Header } from '@/components/Header';
 import { IconButton } from '@/components/IconButton';
@@ -37,7 +38,7 @@ export default function CreateAccountScreen() {
     <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
       <Header
         title="Create account"
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack('/')} />}
       />
       <ScrollView contentContainerStyle={{ padding: 14, paddingBottom: 40 }}>
         <Text style={{ color: '#ffffff', fontSize: 17, fontWeight: '700', marginBottom: 4 }}>
diff --git a/client-app/app/(auth)/import.tsx b/client-app/app/(auth)/import.tsx
index b2208eb..3456b69 100644
--- a/client-app/app/(auth)/import.tsx
+++ b/client-app/app/(auth)/import.tsx
@@ -15,6 +15,7 @@ import * as DocumentPicker from 'expo-document-picker';
 import * as Clipboard from 'expo-clipboard';
 import { saveKeyFile } from '@/lib/storage';
 import { useStore } from '@/lib/store';
+import { safeBack } from '@/lib/utils';
 import type { KeyFile } from '@/lib/types';
 
 import { Header } from '@/components/Header';
@@ -96,7 +97,7 @@ export default function ImportKeyScreen() {
     <View style={{ flex: 1, backgroundColor: '#000000', paddingTop: insets.top }}>
       <Header
         title="Import key"
-        left={<IconButton icon="chevron-back" size={36} onPress={() => router.back()} />}
+        left={<IconButton icon="chevron-back" size={36} onPress={() => safeBack('/')} />}
       />
       <ScrollView
         contentContainerStyle={{ padding: 14, paddingBottom: 40 }}
diff --git a/client-app/lib/utils.ts b/client-app/lib/utils.ts
index 19f61f5..c9f502f 100644
--- a/client-app/lib/utils.ts
+++ b/client-app/lib/utils.ts
@@ -1,5 +1,23 @@
 import { clsx, type ClassValue } from 'clsx';
 import { twMerge } from 'tailwind-merge';
+import { router } from 'expo-router';
+
+/**
+ * Navigate back, or fall back to a sensible default route if there's
+ * no screen to pop to.
+ *
+ * Without this, an opened route entered via deep link / direct push
+ * (profile, feed/[id], etc.) would emit the "action 'GO_BACK' was not
+ * handled by any navigator" dev warning and do nothing — user ends up
+ * stuck. Default fallback is the chats list (root of the app).
+ */
+export function safeBack(fallback: string = '/(app)/chats'): void {
+  if (router.canGoBack()) {
+    router.back();
+  } else {
+    router.replace(fallback as never);
+  }
+}
 
 export function cn(...inputs: ClassValue[]) {
   return twMerge(clsx(inputs));