diff --git a/desktop/src-tauri/src/commands/identity.rs b/desktop/src-tauri/src/commands/identity.rs
index 1940ae1d0ad..482fc4fb4b0 100644
--- a/desktop/src-tauri/src/commands/identity.rs
+++ b/desktop/src-tauri/src/commands/identity.rs
@@ -59,6 +59,14 @@ pub fn sign_event(
     Ok(event.as_json())
 }
 
+#[tauri::command]
+pub fn get_nsec(state: State<'_, AppState>) -> Result<String, String> {
+    let keys = state.keys.lock().map_err(|error| error.to_string())?;
+    keys.secret_key()
+        .to_bech32()
+        .map_err(|error| format!("encode nsec: {error}"))
+}
+
 #[tauri::command]
 pub fn create_auth_event(
     challenge: String,
diff --git a/desktop/src-tauri/src/lib.rs b/desktop/src-tauri/src/lib.rs
index 97206a95a82..57e2ccfcec2 100644
--- a/desktop/src-tauri/src/lib.rs
+++ b/desktop/src-tauri/src/lib.rs
@@ -530,6 +530,7 @@ pub fn run() {
         })
         .invoke_handler(tauri::generate_handler![
             get_identity,
+            get_nsec,
             get_profile,
             update_profile,
             get_user_profile,
diff --git a/desktop/src/features/settings/ui/MobilePairingCard.tsx b/desktop/src/features/settings/ui/MobilePairingCard.tsx
index d2b7a1bf78d..fc129ec4661 100644
--- a/desktop/src/features/settings/ui/MobilePairingCard.tsx
+++ b/desktop/src/features/settings/ui/MobilePairingCard.tsx
@@ -3,7 +3,7 @@ import { QRCodeSVG } from "qrcode.react";
 import { Check, Copy, Loader2, Smartphone, TriangleAlert } from "lucide-react";
 
 import { useMintTokenMutation } from "@/features/tokens/hooks";
-import { getRelayHttpUrl } from "@/shared/api/tauri";
+import { getNsec, getRelayHttpUrl } from "@/shared/api/tauri";
 import type { TokenScope } from "@/shared/api/types";
 import { Button } from "@/shared/ui/button";
 import {
@@ -31,6 +31,7 @@ type PairingPayload = {
   relayUrl: string;
   token: string;
   pubkey: string;
+  nsec: string;
 };
 
 function PairingDialog({
@@ -51,19 +52,21 @@ function PairingDialog({
   const [copied, setCopied] = useState(false);
 
   const generate = useCallback(async (pubkey: string) => {
-    const [tokenResult, relayUrl] = await Promise.all([
+    const [tokenResult, relayUrl, nsec] = await Promise.all([
       mintRef.current({
         name: `mobile-${Date.now()}`,
         scopes: [...MOBILE_SCOPES],
         expiresInDays: EXPIRES_IN_DAYS,
       }),
       getRelayHttpUrl(),
+      getNsec(),
     ]);
 
     const payload: PairingPayload = {
       relayUrl,
       token: tokenResult.token,
       pubkey,
+      nsec,
     };
     return `sprout://${toBase64Url(JSON.stringify(payload))}`;
   }, []);
diff --git a/desktop/src/shared/api/tauri.ts b/desktop/src/shared/api/tauri.ts
index daa55e4e2c9..d373ccac976 100644
--- a/desktop/src/shared/api/tauri.ts
+++ b/desktop/src/shared/api/tauri.ts
@@ -451,6 +451,10 @@ export async function getIdentity(): Promise<Identity> {
   };
 }
 
+export async function getNsec(): Promise<string> {
+  return invokeTauri<string>("get_nsec");
+}
+
 export async function getProfile(): Promise<Profile> {
   const profile = await invokeTauri<RawProfile>("get_profile");
   return fromRawProfile(profile);
diff --git a/mobile/ios/Podfile.lock b/mobile/ios/Podfile.lock
index b7cca0a4283..9e2317ca7dd 100644
--- a/mobile/ios/Podfile.lock
+++ b/mobile/ios/Podfile.lock
@@ -1,4 +1,6 @@
 PODS:
+  - connectivity_plus (0.0.1):
+    - Flutter
   - Flutter (1.0.0)
   - flutter_secure_storage (6.0.0):
     - Flutter
@@ -56,6 +58,7 @@ PODS:
     - FlutterMacOS
 
 DEPENDENCIES:
+  - connectivity_plus (from `.symlinks/plugins/connectivity_plus/ios`)
   - Flutter (from `Flutter`)
   - flutter_secure_storage (from `.symlinks/plugins/flutter_secure_storage/ios`)
   - mobile_scanner (from `.symlinks/plugins/mobile_scanner/ios`)
@@ -76,6 +79,8 @@ SPEC REPOS:
     - PromisesObjC
 
 EXTERNAL SOURCES:
+  connectivity_plus:
+    :path: ".symlinks/plugins/connectivity_plus/ios"
   Flutter:
     :path: Flutter
   flutter_secure_storage:
@@ -86,6 +91,7 @@ EXTERNAL SOURCES:
     :path: ".symlinks/plugins/shared_preferences_foundation/darwin"
 
 SPEC CHECKSUMS:
+  connectivity_plus: cb623214f4e1f6ef8fe7403d580fdad517d2f7dd
   Flutter: cabc95a1d2626b1b06e7179b784ebcf0c0cde467
   flutter_secure_storage: 1ed9476fba7e7a782b22888f956cce43e2c62f13
   GoogleDataTransport: aae35b7ea0c09004c3797d53c8c41f66f219d6a7
diff --git a/mobile/lib/app.dart b/mobile/lib/app.dart
index e843fa09f70..d92969e0c61 100644
--- a/mobile/lib/app.dart
+++ b/mobile/lib/app.dart
@@ -5,6 +5,7 @@ import 'package:lucide_icons_flutter/lucide_icons.dart';
 import 'features/home/home_page.dart';
 import 'features/pairing/pairing_page.dart';
 import 'shared/auth/auth.dart';
+import 'shared/relay/relay.dart';
 import 'shared/theme/theme.dart';
 
 class App extends HookConsumerWidget {
@@ -19,6 +20,13 @@ class App extends HookConsumerWidget {
     final lightScheme = applyAccent(lightColorScheme, accentIndex);
     final darkScheme = applyAccent(darkColorScheme, accentIndex);
 
+    // Eagerly initialize websocket session and lifecycle observer when
+    // authenticated. These providers connect and manage the websocket.
+    if (authState.value?.status == AuthStatus.authenticated) {
+      ref.watch(relaySessionProvider);
+      ref.watch(appLifecycleProvider);
+    }
+
     return MaterialApp(
       title: 'Sprout',
       theme: AppTheme.light(colorScheme: lightScheme),
diff --git a/mobile/lib/features/channels/channel.dart b/mobile/lib/features/channels/channel.dart
index 5a828a43b4b..f6f5dcff56b 100644
--- a/mobile/lib/features/channels/channel.dart
+++ b/mobile/lib/features/channels/channel.dart
@@ -61,4 +61,21 @@ class Channel {
   bool get isForum => channelType == 'forum';
   bool get isDm => channelType == 'dm';
   bool get isPrivate => visibility == 'private';
+
+  Channel copyWith({DateTime? lastMessageAt}) => Channel(
+    id: id,
+    name: name,
+    channelType: channelType,
+    visibility: visibility,
+    description: description,
+    topic: topic,
+    purpose: purpose,
+    createdBy: createdBy,
+    createdAt: createdAt,
+    memberCount: memberCount,
+    lastMessageAt: lastMessageAt ?? this.lastMessageAt,
+    isMember: isMember,
+    ttlSeconds: ttlSeconds,
+    ttlDeadline: ttlDeadline,
+  );
 }
diff --git a/mobile/lib/features/channels/channel_detail_page.dart b/mobile/lib/features/channels/channel_detail_page.dart
new file mode 100644
index 00000000000..4ddd1bd52f7
--- /dev/null
+++ b/mobile/lib/features/channels/channel_detail_page.dart
@@ -0,0 +1,411 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_hooks/flutter_hooks.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:lucide_icons_flutter/lucide_icons.dart';
+
+import '../../shared/relay/relay.dart';
+import '../../shared/theme/theme.dart';
+import '../profile/user_cache_provider.dart';
+import '../profile/user_profile.dart';
+import 'channel.dart';
+import 'channel_messages_provider.dart';
+import 'channel_typing_provider.dart';
+import 'send_message_provider.dart';
+
+/// Fetch channel members and preload their profiles into the user cache.
+Future<void> _preloadMembers(WidgetRef ref, String channelId) async {
+  try {
+    final client = ref.read(relayClientProvider);
+    final json =
+        await client.get('/api/channels/$channelId/members')
+            as Map<String, dynamic>;
+    final members = json['members'] as List<dynamic>? ?? [];
+    final pubkeys = members
+        .map((m) => (m as Map<String, dynamic>)['pubkey'] as String)
+        .toList();
+    if (pubkeys.isNotEmpty) {
+      ref.read(userCacheProvider.notifier).preload(pubkeys);
+    }
+  } catch (_) {
+    // Non-fatal — mentions will just fall back to cache from messages.
+  }
+}
+
+class ChannelDetailPage extends HookConsumerWidget {
+  final Channel channel;
+
+  const ChannelDetailPage({super.key, required this.channel});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final messagesState = ref.watch(channelMessagesProvider(channel.id));
+    final typingEntries = ref.watch(channelTypingProvider(channel.id));
+
+    // Preload channel member profiles so @mentions resolve correctly.
+    useEffect(() {
+      _preloadMembers(ref, channel.id);
+      return null;
+    }, [channel.id]);
+
+    return Scaffold(
+      appBar: AppBar(
+        title: Row(
+          children: [
+            Icon(
+              channel.isPrivate ? LucideIcons.lock : LucideIcons.hash,
+              size: 18,
+              color: context.colors.onSurfaceVariant,
+            ),
+            const SizedBox(width: Grid.half),
+            Expanded(
+              child: Text(channel.name, overflow: TextOverflow.ellipsis),
+            ),
+          ],
+        ),
+      ),
+      body: Column(
+        children: [
+          Expanded(
+            child: messagesState.when(
+              loading: () => const Center(child: CircularProgressIndicator()),
+              error: (e, _) => Center(
+                child: Text(
+                  'Failed to load messages',
+                  style: context.textTheme.bodyMedium?.copyWith(
+                    color: context.colors.error,
+                  ),
+                ),
+              ),
+              data: (messages) =>
+                  _MessageList(messages: messages, channelId: channel.id),
+            ),
+          ),
+          if (typingEntries.isNotEmpty)
+            _TypingIndicator(entries: typingEntries),
+          _ComposeBar(channelId: channel.id),
+        ],
+      ),
+    );
+  }
+}
+
+class _MessageList extends ConsumerWidget {
+  final List<NostrEvent> messages;
+  final String channelId;
+
+  const _MessageList({required this.messages, required this.channelId});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    if (messages.isEmpty) {
+      return Center(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: [
+            Icon(
+              LucideIcons.messageSquare,
+              size: Grid.xl,
+              color: context.colors.outline,
+            ),
+            const SizedBox(height: Grid.xxs),
+            Text(
+              'No messages yet',
+              style: context.textTheme.bodyLarge?.copyWith(
+                color: context.colors.onSurfaceVariant,
+              ),
+            ),
+            const SizedBox(height: Grid.half),
+            Text(
+              'Be the first to say something!',
+              style: context.textTheme.bodySmall?.copyWith(
+                color: context.colors.outline,
+              ),
+            ),
+          ],
+        ),
+      );
+    }
+
+    // Filter to only renderable message events for display and grouping.
+    final displayMessages = messages
+        .where(
+          (e) =>
+              e.kind == EventKind.streamMessage ||
+              e.kind == EventKind.streamMessageV2,
+        )
+        .toList();
+
+    return ListView.builder(
+      reverse: true,
+      padding: const EdgeInsets.symmetric(
+        horizontal: Grid.xs,
+        vertical: Grid.xxs,
+      ),
+      itemCount: displayMessages.length,
+      itemBuilder: (context, index) {
+        // Reversed list: index 0 = newest (bottom of screen).
+        final chronIdx = displayMessages.length - 1 - index;
+        final message = displayMessages[chronIdx];
+        // The message visually above is the one earlier in time.
+        final prevMessage = chronIdx > 0 ? displayMessages[chronIdx - 1] : null;
+
+        final showAuthor =
+            prevMessage == null ||
+            prevMessage.pubkey.toLowerCase() != message.pubkey.toLowerCase() ||
+            (message.createdAt - prevMessage.createdAt) > 300;
+
+        return _MessageBubble(event: message, showAuthor: showAuthor);
+      },
+    );
+  }
+}
+
+class _MessageBubble extends ConsumerWidget {
+  final NostrEvent event;
+  final bool showAuthor;
+
+  const _MessageBubble({required this.event, required this.showAuthor});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    // Look up the user profile for display name.
+    final userCache = ref.watch(userCacheProvider);
+    final profile =
+        userCache[event.pubkey.toLowerCase()] ??
+        ref.read(userCacheProvider.notifier).get(event.pubkey.toLowerCase());
+    final displayName = profile?.label ?? _shortPubkey(event.pubkey);
+
+    return Padding(
+      padding: EdgeInsets.only(top: showAuthor ? Grid.xxs : Grid.quarter),
+      child: Row(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          if (showAuthor)
+            _UserAvatar(profile: profile, pubkey: event.pubkey)
+          else
+            const SizedBox(width: 28),
+          const SizedBox(width: Grid.xxs),
+          Expanded(
+            child: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                if (showAuthor)
+                  Padding(
+                    padding: const EdgeInsets.only(bottom: Grid.quarter),
+                    child: Row(
+                      children: [
+                        Text(
+                          displayName,
+                          style: context.textTheme.labelMedium?.copyWith(
+                            fontWeight: FontWeight.w600,
+                            color: context.colors.onSurface,
+                          ),
+                        ),
+                        const SizedBox(width: Grid.xxs),
+                        Text(
+                          _formatTime(event.createdAt),
+                          style: context.textTheme.labelSmall?.copyWith(
+                            color: context.colors.outline,
+                          ),
+                        ),
+                      ],
+                    ),
+                  ),
+                Text(
+                  event.content,
+                  style: context.textTheme.bodyMedium?.copyWith(
+                    color: context.colors.onSurface,
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  static String _shortPubkey(String pubkey) {
+    if (pubkey.length > 12) {
+      return '${pubkey.substring(0, 8)}…';
+    }
+    return pubkey;
+  }
+
+  static String _formatTime(int createdAt) {
+    final dt = DateTime.fromMillisecondsSinceEpoch(
+      createdAt * 1000,
+      isUtc: true,
+    ).toLocal();
+    final now = DateTime.now();
+    final diff = now.difference(dt);
+
+    if (diff.inDays > 0) {
+      return '${dt.month}/${dt.day} ${_pad(dt.hour)}:${_pad(dt.minute)}';
+    }
+    return '${_pad(dt.hour)}:${_pad(dt.minute)}';
+  }
+
+  static String _pad(int n) => n.toString().padLeft(2, '0');
+}
+
+class _UserAvatar extends StatelessWidget {
+  final UserProfile? profile;
+  final String pubkey;
+
+  const _UserAvatar({required this.profile, required this.pubkey});
+
+  @override
+  Widget build(BuildContext context) {
+    final initial =
+        profile?.initial ?? (pubkey.isNotEmpty ? pubkey[0].toUpperCase() : '?');
+    final avatarUrl = profile?.avatarUrl;
+
+    return CircleAvatar(
+      radius: 14,
+      backgroundColor: context.colors.primaryContainer,
+      backgroundImage: avatarUrl != null ? NetworkImage(avatarUrl) : null,
+      child: avatarUrl == null
+          ? Text(
+              initial,
+              style: context.textTheme.labelSmall?.copyWith(
+                color: context.colors.onPrimaryContainer,
+                fontWeight: FontWeight.w600,
+              ),
+            )
+          : null,
+    );
+  }
+}
+
+class _TypingIndicator extends ConsumerWidget {
+  final List<TypingEntry> entries;
+
+  const _TypingIndicator({required this.entries});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final userCache = ref.watch(userCacheProvider);
+    final names = entries.map((e) {
+      final profile =
+          userCache[e.pubkey.toLowerCase()] ??
+          ref.read(userCacheProvider.notifier).get(e.pubkey.toLowerCase());
+      return profile?.label ?? _shortPubkey(e.pubkey);
+    }).toList();
+    final text = switch (names.length) {
+      1 => '${names[0]} is typing…',
+      2 => '${names[0]} and ${names[1]} are typing…',
+      _ => '${names[0]} and ${names.length - 1} others are typing…',
+    };
+
+    return Container(
+      width: double.infinity,
+      padding: const EdgeInsets.symmetric(
+        horizontal: Grid.xs,
+        vertical: Grid.quarter + 2,
+      ),
+      child: Text(
+        text,
+        style: context.textTheme.labelSmall?.copyWith(
+          color: context.colors.outline,
+          fontStyle: FontStyle.italic,
+        ),
+      ),
+    );
+  }
+
+  static String _shortPubkey(String pubkey) {
+    if (pubkey.length > 12) return '${pubkey.substring(0, 8)}…';
+    return pubkey;
+  }
+}
+
+class _ComposeBar extends HookConsumerWidget {
+  final String channelId;
+
+  const _ComposeBar({required this.channelId});
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final controller = useTextEditingController();
+    final isSending = useState(false);
+
+    Future<void> send() async {
+      final text = controller.text.trim();
+      if (text.isEmpty || isSending.value) return;
+
+      isSending.value = true;
+      try {
+        await ref
+            .read(sendMessageProvider)
+            .call(channelId: channelId, content: text);
+        controller.clear();
+      } finally {
+        isSending.value = false;
+      }
+    }
+
+    return Container(
+      decoration: BoxDecoration(
+        border: Border(top: BorderSide(color: context.colors.outlineVariant)),
+        color: context.colors.surface,
+      ),
+      padding: EdgeInsets.only(
+        left: Grid.xs,
+        right: Grid.xxs,
+        top: Grid.xxs,
+        bottom: MediaQuery.viewPaddingOf(context).bottom + Grid.xxs,
+      ),
+      child: Row(
+        children: [
+          Expanded(
+            child: TextField(
+              controller: controller,
+              textInputAction: TextInputAction.send,
+              onSubmitted: (_) => send(),
+              minLines: 1,
+              maxLines: 5,
+              decoration: InputDecoration(
+                hintText: 'Message…',
+                border: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(Radii.lg),
+                  borderSide: BorderSide(color: context.colors.outlineVariant),
+                ),
+                enabledBorder: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(Radii.lg),
+                  borderSide: BorderSide(color: context.colors.outlineVariant),
+                ),
+                focusedBorder: OutlineInputBorder(
+                  borderRadius: BorderRadius.circular(Radii.lg),
+                  borderSide: BorderSide(color: context.colors.primary),
+                ),
+                contentPadding: const EdgeInsets.symmetric(
+                  horizontal: Grid.twelve,
+                  vertical: Grid.xxs,
+                ),
+                isDense: true,
+              ),
+            ),
+          ),
+          const SizedBox(width: Grid.half),
+          IconButton(
+            onPressed: isSending.value ? null : send,
+            icon: isSending.value
+                ? SizedBox(
+                    width: 20,
+                    height: 20,
+                    child: CircularProgressIndicator(
+                      strokeWidth: 2,
+                      color: context.colors.primary,
+                    ),
+                  )
+                : Icon(
+                    LucideIcons.sendHorizontal,
+                    color: context.colors.primary,
+                  ),
+          ),
+        ],
+      ),
+    );
+  }
+}
diff --git a/mobile/lib/features/channels/channel_messages_provider.dart b/mobile/lib/features/channels/channel_messages_provider.dart
new file mode 100644
index 00000000000..ac9e1da4aff
--- /dev/null
+++ b/mobile/lib/features/channels/channel_messages_provider.dart
@@ -0,0 +1,114 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/relay/relay.dart';
+
+/// Provides the message list for a specific channel. Fetches history on init,
+/// then subscribes to live events via the websocket session.
+class ChannelMessagesNotifier extends Notifier<AsyncValue<List<NostrEvent>>> {
+  final String channelId;
+  void Function()? _unsubscribe;
+
+  ChannelMessagesNotifier(this.channelId);
+
+  @override
+  AsyncValue<List<NostrEvent>> build() {
+    final sessionState = ref.watch(relaySessionProvider);
+    ref.onDispose(() {
+      _unsubscribe?.call();
+      _unsubscribe = null;
+    });
+
+    if (sessionState.status != SessionStatus.connected) {
+      return const AsyncData([]);
+    }
+
+    _init();
+    return const AsyncLoading();
+  }
+
+  Future<void> _init() async {
+    try {
+      final session = ref.read(relaySessionProvider.notifier);
+
+      // 1. Fetch recent history via REQ/EOSE.
+      final history = await session.fetchHistory(
+        NostrFilter(
+          kinds: EventKind.channelEventKinds,
+          tags: {
+            '#h': [channelId],
+          },
+          limit: 50,
+        ),
+      );
+
+      // 2. Subscribe to live events for this channel.
+      _unsubscribe = await session.subscribe(
+        NostrFilter(
+          kinds: EventKind.channelEventKinds,
+          tags: {
+            '#h': [channelId],
+          },
+          limit: 0,
+        ),
+        _handleLiveEvent,
+      );
+
+      history.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+      state = AsyncData(history);
+    } catch (e, st) {
+      state = AsyncError(e, st);
+    }
+  }
+
+  void _handleLiveEvent(NostrEvent event) {
+    state = state.whenData((events) => _mergeEvent(events, event));
+  }
+
+  /// Merge a new event into the sorted list, deduplicating by ID.
+  static List<NostrEvent> _mergeEvent(
+    List<NostrEvent> current,
+    NostrEvent incoming,
+  ) {
+    if (current.any((e) => e.id == incoming.id)) return current;
+    final updated = [...current, incoming];
+    updated.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+    return updated;
+  }
+
+  /// Fetch older messages (pagination). Call this when the user scrolls up.
+  Future<void> fetchOlder() async {
+    final currentEvents = state.value;
+    if (currentEvents == null || currentEvents.isEmpty) return;
+
+    final oldest = currentEvents.first.createdAt;
+    final session = ref.read(relaySessionProvider.notifier);
+
+    final older = await session.fetchHistory(
+      NostrFilter(
+        kinds: EventKind.channelEventKinds,
+        tags: {
+          '#h': [channelId],
+        },
+        limit: 50,
+        until: oldest,
+      ),
+    );
+
+    if (older.isEmpty) return;
+
+    state = state.whenData((events) {
+      final ids = events.map((e) => e.id).toSet();
+      final deduped = older.where((e) => !ids.contains(e.id)).toList();
+      final merged = [...deduped, ...events];
+      merged.sort((a, b) => a.createdAt.compareTo(b.createdAt));
+      return merged;
+    });
+  }
+}
+
+final channelMessagesProvider =
+    NotifierProvider.family<
+      ChannelMessagesNotifier,
+      AsyncValue<List<NostrEvent>>,
+      String
+    >(ChannelMessagesNotifier.new);
diff --git a/mobile/lib/features/channels/channel_typing_provider.dart b/mobile/lib/features/channels/channel_typing_provider.dart
new file mode 100644
index 00000000000..73c7990ca2e
--- /dev/null
+++ b/mobile/lib/features/channels/channel_typing_provider.dart
@@ -0,0 +1,113 @@
+import 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/relay/relay.dart';
+
+/// A single typing indicator entry.
+@immutable
+class TypingEntry {
+  final String pubkey;
+  final String? threadHeadId;
+  final int expiresAtMs;
+
+  const TypingEntry({
+    required this.pubkey,
+    this.threadHeadId,
+    required this.expiresAtMs,
+  });
+}
+
+/// Tracks who is currently typing in a specific channel.
+///
+/// Subscribes to kind:20002 (typing indicator) events via websocket.
+/// Entries expire after 8 seconds (matching the desktop TTL).
+class ChannelTypingNotifier extends Notifier<List<TypingEntry>> {
+  static const _ttlMs = 8000;
+  static const _pruneIntervalMs = 1000;
+
+  final String channelId;
+  void Function()? _unsubscribe;
+  Timer? _pruneTimer;
+
+  ChannelTypingNotifier(this.channelId);
+
+  @override
+  List<TypingEntry> build() {
+    final sessionState = ref.watch(relaySessionProvider);
+
+    ref.onDispose(() {
+      _unsubscribe?.call();
+      _unsubscribe = null;
+      _pruneTimer?.cancel();
+      _pruneTimer = null;
+    });
+
+    if (sessionState.status == SessionStatus.connected) {
+      _subscribeLive();
+    }
+
+    return [];
+  }
+
+  void _subscribeLive() async {
+    final session = ref.read(relaySessionProvider.notifier);
+    _unsubscribe = await session.subscribe(
+      NostrFilter(
+        kinds: [EventKind.typingIndicator],
+        tags: {
+          '#h': [channelId],
+        },
+        limit: 10,
+      ),
+      _handleTypingEvent,
+    );
+  }
+
+  void _handleTypingEvent(NostrEvent event) {
+    final now = DateTime.now().millisecondsSinceEpoch;
+    final entry = TypingEntry(
+      pubkey: event.pubkey,
+      threadHeadId: event.getTagValue('e'),
+      expiresAtMs: now + _ttlMs,
+    );
+
+    // Upsert: replace existing entry for same pubkey+thread, or add.
+    final updated =
+        state
+            .where(
+              (e) =>
+                  !(e.pubkey == entry.pubkey &&
+                      e.threadHeadId == entry.threadHeadId),
+            )
+            .toList()
+          ..add(entry);
+
+    state = updated;
+    _ensurePruneTimer();
+  }
+
+  void _ensurePruneTimer() {
+    _pruneTimer ??= Timer.periodic(
+      const Duration(milliseconds: _pruneIntervalMs),
+      (_) => _prune(),
+    );
+  }
+
+  void _prune() {
+    final now = DateTime.now().millisecondsSinceEpoch;
+    final pruned = state.where((e) => e.expiresAtMs > now).toList();
+    state = pruned;
+
+    if (pruned.isEmpty) {
+      _pruneTimer?.cancel();
+      _pruneTimer = null;
+    }
+  }
+}
+
+final channelTypingProvider =
+    NotifierProvider.family<ChannelTypingNotifier, List<TypingEntry>, String>(
+      ChannelTypingNotifier.new,
+    );
diff --git a/mobile/lib/features/channels/channels_page.dart b/mobile/lib/features/channels/channels_page.dart
index 560ebf3b4c5..d12ba2c72eb 100644
--- a/mobile/lib/features/channels/channels_page.dart
+++ b/mobile/lib/features/channels/channels_page.dart
@@ -1,45 +1,43 @@
-import 'dart:async';
 import 'dart:io';
 
 import 'package:flutter/material.dart';
-import 'package:flutter_hooks/flutter_hooks.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
 
-import '../../shared/relay/relay_client.dart';
+import '../../shared/relay/relay.dart';
 import '../../shared/theme/theme.dart';
 import '../profile/profile_avatar.dart';
 import 'channel.dart';
+import 'channel_detail_page.dart';
 import 'channels_provider.dart';
 
-class ChannelsPage extends HookConsumerWidget {
+class ChannelsPage extends ConsumerWidget {
   const ChannelsPage({super.key});
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
     final channelsAsync = ref.watch(channelsProvider);
-
-    // Poll every 30s while this page is mounted, matching desktop's pattern.
-    useEffect(() {
-      final timer = Timer.periodic(
-        const Duration(seconds: 30),
-        (_) => ref.read(channelsProvider.notifier).refresh(),
-      );
-      return timer.cancel;
-    }, const []);
+    final sessionState = ref.watch(relaySessionProvider);
 
     return Scaffold(
       appBar: AppBar(
         title: const Text('Sprout'),
         actions: const [ProfileAvatar()],
       ),
-      body: channelsAsync.when(
-        loading: () => const Center(child: CircularProgressIndicator()),
-        error: (error, _) => _ErrorView(
-          error: error,
-          onRetry: () => ref.read(channelsProvider.notifier).refresh(),
-        ),
-        data: (channels) => _ChannelsList(channels: channels),
+      body: Column(
+        children: [
+          _ConnectionBanner(status: sessionState.status),
+          Expanded(
+            child: channelsAsync.when(
+              loading: () => const Center(child: CircularProgressIndicator()),
+              error: (error, _) => _ErrorView(
+                error: error,
+                onRetry: () => ref.read(channelsProvider.notifier).refresh(),
+              ),
+              data: (channels) => _ChannelsList(channels: channels),
+            ),
+          ),
+        ],
       ),
     );
   }
@@ -148,7 +146,11 @@ class _ChannelTile extends StatelessWidget {
     return InkWell(
       borderRadius: BorderRadius.circular(Radii.md),
       onTap: () {
-        // TODO: navigate to channel
+        Navigator.of(context).push(
+          MaterialPageRoute<void>(
+            builder: (_) => ChannelDetailPage(channel: channel),
+          ),
+        );
       },
       child: Padding(
         padding: const EdgeInsets.symmetric(
@@ -279,6 +281,53 @@ class _EphemeralBadge extends StatelessWidget {
   }
 }
 
+/// Slim banner shown when the websocket is reconnecting or disconnected.
+class _ConnectionBanner extends StatelessWidget {
+  final SessionStatus status;
+
+  const _ConnectionBanner({required this.status});
+
+  @override
+  Widget build(BuildContext context) {
+    if (status == SessionStatus.connected ||
+        status == SessionStatus.disconnected) {
+      return const SizedBox.shrink();
+    }
+
+    final isConnecting = status == SessionStatus.connecting;
+    final message = isConnecting ? 'Connecting…' : 'Reconnecting…';
+
+    return Container(
+      width: double.infinity,
+      padding: const EdgeInsets.symmetric(
+        horizontal: Grid.xs,
+        vertical: Grid.quarter + 2,
+      ),
+      color: context.colors.surfaceContainerHighest,
+      child: Row(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: [
+          SizedBox(
+            width: 12,
+            height: 12,
+            child: CircularProgressIndicator(
+              strokeWidth: 2,
+              color: context.colors.onSurfaceVariant,
+            ),
+          ),
+          const SizedBox(width: Grid.xxs),
+          Text(
+            message,
+            style: context.textTheme.labelSmall?.copyWith(
+              color: context.colors.onSurfaceVariant,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}
+
 class _ErrorView extends StatelessWidget {
   final Object error;
   final VoidCallback onRetry;
diff --git a/mobile/lib/features/channels/channels_provider.dart b/mobile/lib/features/channels/channels_provider.dart
index 164535bd3d6..c6804e1aef0 100644
--- a/mobile/lib/features/channels/channels_provider.dart
+++ b/mobile/lib/features/channels/channels_provider.dart
@@ -4,11 +4,28 @@ import '../../shared/relay/relay.dart';
 import 'channel.dart';
 
 class ChannelsNotifier extends AsyncNotifier<List<Channel>> {
+  void Function()? _unsubscribe;
+
   @override
   Future<List<Channel>> build() {
-    // Watch relayClientProvider here so we auto-refetch when config changes.
     ref.watch(relayClientProvider);
-    return _fetch();
+    final sessionState = ref.watch(relaySessionProvider);
+
+    ref.onDispose(() {
+      _unsubscribe?.call();
+      _unsubscribe = null;
+    });
+
+    // Initial fetch via HTTP (reliable, paginated).
+    final fetchFuture = _fetch();
+
+    // If websocket is connected, subscribe to live channel events to keep
+    // the list up to date without polling.
+    if (sessionState.status == SessionStatus.connected) {
+      _subscribeLive();
+    }
+
+    return fetchFuture;
   }
 
   Future<List<Channel>> _fetch() async {
@@ -23,6 +40,40 @@ class ChannelsNotifier extends AsyncNotifier<List<Channel>> {
     return channels;
   }
 
+  void _subscribeLive() async {
+    final session = ref.read(relaySessionProvider.notifier);
+    _unsubscribe = await session.subscribe(
+      NostrFilter(kinds: EventKind.channelEventKinds, limit: 0),
+      _handleLiveEvent,
+    );
+  }
+
+  void _handleLiveEvent(NostrEvent event) {
+    final channelId = event.channelId;
+    if (channelId == null) return;
+
+    state = state.whenData((channels) {
+      final idx = channels.indexWhere((c) => c.id == channelId);
+      if (idx == -1) {
+        // Unknown channel — queue a full refresh to pick it up.
+        refresh();
+        return channels;
+      }
+      // Update lastMessageAt for the affected channel.
+      final updated = List<Channel>.of(channels);
+      final channel = updated[idx];
+      final eventTime = DateTime.fromMillisecondsSinceEpoch(
+        event.createdAt * 1000,
+        isUtc: true,
+      );
+      if (channel.lastMessageAt == null ||
+          eventTime.isAfter(channel.lastMessageAt!)) {
+        updated[idx] = channel.copyWith(lastMessageAt: eventTime);
+      }
+      return updated;
+    });
+  }
+
   Future<void> refresh() async {
     state = await AsyncValue.guard(_fetch);
   }
diff --git a/mobile/lib/features/channels/send_message_provider.dart b/mobile/lib/features/channels/send_message_provider.dart
new file mode 100644
index 00000000000..12caeac63c0
--- /dev/null
+++ b/mobile/lib/features/channels/send_message_provider.dart
@@ -0,0 +1,114 @@
+import 'dart:convert';
+
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:nostr/nostr.dart' as nostr;
+
+import '../../shared/relay/relay.dart';
+import '../profile/user_cache_provider.dart';
+import '../profile/user_profile.dart';
+
+/// Sends messages via the relay HTTP API. The event is signed on the client
+/// with the user's nsec, then POSTed as a full signed Nostr event — matching
+/// what the desktop does via `submit_event`.
+class SendMessage {
+  final RelayClient _client;
+  final String? _nsec;
+  final Map<String, UserProfile> Function() _readUserCache;
+
+  SendMessage({
+    required RelayClient client,
+    required String? nsec,
+    required Map<String, UserProfile> Function() readUserCache,
+  }) : _client = client,
+       _nsec = nsec,
+       _readUserCache = readUserCache;
+
+  /// Send a text message to a channel.
+  Future<void> call({
+    required String channelId,
+    required String content,
+    String? parentEventId,
+    List<String>? mentionPubkeys,
+  }) async {
+    final nsec = _nsec;
+    if (nsec == null || nsec.isEmpty) {
+      throw Exception('Cannot send messages: no signing key available');
+    }
+
+    // Decode bech32 nsec to hex private key.
+    final privkeyHex = nostr.Nip19.decodePrivkey(nsec);
+    if (privkeyHex.isEmpty) {
+      throw Exception('Invalid nsec');
+    }
+
+    // Resolve @mentions in the message content to pubkeys.
+    final resolvedMentions = mentionPubkeys ?? _resolveMentions(content);
+
+    final tags = <List<String>>[
+      ['h', channelId],
+      if (parentEventId != null) ['e', parentEventId],
+      for (final pk in resolvedMentions) ['p', pk],
+    ];
+
+    // Create and sign the event using the nostr package.
+    final event = nostr.Event.from(
+      kind: EventKind.streamMessage,
+      content: content,
+      tags: tags,
+      privkey: privkeyHex,
+      verify: false,
+    );
+
+    // POST the full signed event JSON to the relay.
+    final response = await _client.postRaw(
+      '/api/events',
+      body: jsonEncode(event.toJson()),
+    );
+
+    final result = jsonDecode(response) as Map<String, dynamic>;
+    if (result['accepted'] != true) {
+      throw Exception(result['message'] ?? 'Event rejected by relay');
+    }
+  }
+
+  /// Parse @mentions from message content and resolve to pubkeys using
+  /// the user cache. Reads the cache at call time (not construction time)
+  /// to ensure freshly loaded profiles are available.
+  List<String> _resolveMentions(String content) {
+    final mentionPattern = RegExp(r'@(\w+)');
+    final matches = mentionPattern.allMatches(content);
+    final pubkeys = <String>{};
+
+    // Read the current cache state at send time.
+    final cache = _readUserCache();
+
+    for (final match in matches) {
+      final name = match.group(1)?.toLowerCase();
+      if (name == null || name.isEmpty) continue;
+
+      for (final profile in cache.values) {
+        final displayName = profile.displayName?.toLowerCase();
+        if (displayName == null) continue;
+
+        // Match against full display name or first word of it.
+        final firstName = displayName.split(RegExp(r'\s+')).first;
+        if (displayName == name || firstName == name) {
+          pubkeys.add(profile.pubkey);
+          break;
+        }
+      }
+    }
+
+    return pubkeys.toList();
+  }
+}
+
+final sendMessageProvider = Provider<SendMessage>((ref) {
+  final client = ref.watch(relayClientProvider);
+  final config = ref.watch(relayConfigProvider);
+  return SendMessage(
+    client: client,
+    nsec: config.nsec,
+    readUserCache: () => ref.read(userCacheProvider),
+  );
+});
diff --git a/mobile/lib/features/pairing/pairing_provider.dart b/mobile/lib/features/pairing/pairing_provider.dart
index e4f20be7a12..f639f07a981 100644
--- a/mobile/lib/features/pairing/pairing_provider.dart
+++ b/mobile/lib/features/pairing/pairing_provider.dart
@@ -109,6 +109,7 @@ class PairingNotifier extends Notifier<PairingState> {
       relayUrl: relayUrl,
       token: token,
       pubkey: decoded['pubkey'] as String?,
+      nsec: decoded['nsec'] as String?,
     );
   }
 
diff --git a/mobile/lib/features/profile/profile_provider.dart b/mobile/lib/features/profile/profile_provider.dart
index a5c7ffc4feb..eaa0ad9d3af 100644
--- a/mobile/lib/features/profile/profile_provider.dart
+++ b/mobile/lib/features/profile/profile_provider.dart
@@ -1,3 +1,6 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
 import '../../shared/relay/relay.dart';
@@ -33,14 +36,56 @@ final profileProvider = AsyncNotifierProvider<ProfileNotifier, UserProfile?>(
 );
 
 /// Presence status for the current user.
+///
+/// Sends a heartbeat every 60s while the app is active. Watches
+/// [appLifecycleProvider] to send "away" when backgrounded.
 class PresenceNotifier extends AsyncNotifier<String> {
+  static const _heartbeatInterval = Duration(seconds: 60);
+
+  Timer? _heartbeatTimer;
+
   @override
   Future<String> build() {
     ref.watch(relayClientProvider);
     ref.watch(profileProvider);
+
+    final lifecycle = ref.watch(appLifecycleProvider);
+
+    ref.onDispose(() {
+      _heartbeatTimer?.cancel();
+      _heartbeatTimer = null;
+    });
+
+    if (lifecycle == AppLifecycleState.resumed) {
+      _startHeartbeat();
+      return _setPresence('online');
+    } else if (lifecycle == AppLifecycleState.paused ||
+        lifecycle == AppLifecycleState.detached) {
+      _heartbeatTimer?.cancel();
+      _heartbeatTimer = null;
+      return _setPresence('away');
+    }
+
     return _fetch();
   }
 
+  void _startHeartbeat() {
+    _heartbeatTimer?.cancel();
+    _heartbeatTimer = Timer.periodic(_heartbeatInterval, (_) {
+      _setPresence('online');
+    });
+  }
+
+  Future<String> _setPresence(String status) async {
+    final client = ref.read(relayClientProvider);
+    try {
+      await client.post('/api/presence', body: {'status': status});
+      return status;
+    } catch (_) {
+      return state.value ?? 'offline';
+    }
+  }
+
   Future<String> _fetch() async {
     final profile = ref.read(profileProvider).whenData((v) => v).value;
     if (profile == null) return 'offline';
diff --git a/mobile/lib/features/profile/user_cache_provider.dart b/mobile/lib/features/profile/user_cache_provider.dart
new file mode 100644
index 00000000000..60d06598a17
--- /dev/null
+++ b/mobile/lib/features/profile/user_cache_provider.dart
@@ -0,0 +1,86 @@
+import 'dart:async';
+
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/relay/relay.dart';
+import 'user_profile.dart';
+
+/// In-memory cache of user profiles, fetched in batches from the relay.
+class UserCacheNotifier extends Notifier<Map<String, UserProfile>> {
+  final Set<String> _pending = {};
+  Timer? _batchTimer;
+
+  @override
+  Map<String, UserProfile> build() {
+    ref.watch(relayClientProvider);
+    ref.onDispose(() {
+      _batchTimer?.cancel();
+      _batchTimer = null;
+    });
+    return {};
+  }
+
+  /// Request a profile for [pubkey]. Returns immediately from cache if
+  /// available, otherwise schedules a batch fetch.
+  UserProfile? get(String pubkey) {
+    final cached = state[pubkey];
+    if (cached != null) return cached;
+    _scheduleFetch(pubkey);
+    return null;
+  }
+
+  /// Preload profiles for a list of pubkeys (e.g. channel members).
+  void preload(List<String> pubkeys) {
+    final uncached = pubkeys
+        .map((pk) => pk.toLowerCase())
+        .where((pk) => !state.containsKey(pk) && !_pending.contains(pk))
+        .toList();
+    if (uncached.isEmpty) return;
+    _pending.addAll(uncached);
+    _batchTimer ??= Timer(const Duration(milliseconds: 50), _flushPending);
+  }
+
+  void _scheduleFetch(String pubkey) {
+    if (_pending.contains(pubkey)) return;
+    _pending.add(pubkey);
+
+    // Batch: wait 50ms to collect multiple lookups into one request.
+    _batchTimer ??= Timer(const Duration(milliseconds: 50), _flushPending);
+  }
+
+  Future<void> _flushPending() async {
+    _batchTimer = null;
+    if (_pending.isEmpty) return;
+
+    final pubkeys = _pending.toList();
+    _pending.clear();
+
+    try {
+      final client = ref.read(relayClientProvider);
+      final json =
+          await client.post('/api/users/batch', body: {'pubkeys': pubkeys})
+              as Map<String, dynamic>;
+
+      final profiles = json['profiles'] as Map<String, dynamic>? ?? {};
+      final updated = Map<String, UserProfile>.from(state);
+
+      for (final entry in profiles.entries) {
+        final data = entry.value as Map<String, dynamic>;
+        updated[entry.key.toLowerCase()] = UserProfile(
+          pubkey: entry.key.toLowerCase(),
+          displayName: data['display_name'] as String?,
+          avatarUrl: data['avatar_url'] as String?,
+        );
+      }
+
+      state = updated;
+    } catch (_) {
+      // Silently fail — we'll just show pubkeys.
+    }
+  }
+}
+
+final userCacheProvider =
+    NotifierProvider<UserCacheNotifier, Map<String, UserProfile>>(
+      UserCacheNotifier.new,
+    );
diff --git a/mobile/lib/features/settings/settings_page.dart b/mobile/lib/features/settings/settings_page.dart
index 9bc532437da..3602afa19ac 100644
--- a/mobile/lib/features/settings/settings_page.dart
+++ b/mobile/lib/features/settings/settings_page.dart
@@ -132,7 +132,7 @@ class SettingsPage extends HookConsumerWidget {
               ref.read(authProvider.notifier).signOut();
             },
             style: FilledButton.styleFrom(
-              backgroundColor: context.colors.error,
+              backgroundColor: Theme.of(ctx).colorScheme.error,
             ),
             child: const Text('Sign Out'),
           ),
diff --git a/mobile/lib/shared/auth/auth_provider.dart b/mobile/lib/shared/auth/auth_provider.dart
index a9bb9ccdeee..1adbfdb146d 100644
--- a/mobile/lib/shared/auth/auth_provider.dart
+++ b/mobile/lib/shared/auth/auth_provider.dart
@@ -1,4 +1,3 @@
-import 'package:flutter/foundation.dart';
 import 'package:hooks_riverpod/hooks_riverpod.dart';
 
 import '../relay/relay.dart';
@@ -16,12 +15,6 @@ class AuthState {
 class AuthNotifier extends AsyncNotifier<AuthState> {
   @override
   Future<AuthState> build() async {
-    // If a token is provided via dart-define in debug mode, treat as
-    // pre-authenticated.
-    if (kDebugMode && Env.apiToken.isNotEmpty) {
-      return const AuthState(status: AuthStatus.authenticated);
-    }
-
     final storage = CredentialStorage();
     final creds = await storage.load();
     if (creds == null) {
@@ -39,6 +32,7 @@ class AuthNotifier extends AsyncNotifier<AuthState> {
             baseUrl: creds.relayUrl,
             apiToken: creds.token,
             devPubkey: null,
+            nsec: creds.nsec,
           );
       return AuthState(status: AuthStatus.authenticated, credentials: creds);
     } on RelayException {
@@ -69,6 +63,7 @@ class AuthNotifier extends AsyncNotifier<AuthState> {
           baseUrl: creds.relayUrl,
           apiToken: creds.token,
           devPubkey: null,
+          nsec: creds.nsec,
         );
 
     state = AsyncData(
diff --git a/mobile/lib/shared/auth/credential_storage.dart b/mobile/lib/shared/auth/credential_storage.dart
index 35a5a160ce8..4ff324f19a3 100644
--- a/mobile/lib/shared/auth/credential_storage.dart
+++ b/mobile/lib/shared/auth/credential_storage.dart
@@ -4,11 +4,13 @@ class StoredCredentials {
   final String relayUrl;
   final String token;
   final String? pubkey;
+  final String? nsec;
 
   const StoredCredentials({
     required this.relayUrl,
     required this.token,
     this.pubkey,
+    this.nsec,
   });
 }
 
@@ -16,6 +18,7 @@ class CredentialStorage {
   static const _keyRelayUrl = 'sprout_relay_url';
   static const _keyToken = 'sprout_token';
   static const _keyPubkey = 'sprout_pubkey';
+  static const _keyNsec = 'sprout_nsec';
 
   final FlutterSecureStorage _storage;
 
@@ -28,7 +31,13 @@ class CredentialStorage {
     if (relayUrl == null || token == null) return null;
 
     final pubkey = await _storage.read(key: _keyPubkey);
-    return StoredCredentials(relayUrl: relayUrl, token: token, pubkey: pubkey);
+    final nsec = await _storage.read(key: _keyNsec);
+    return StoredCredentials(
+      relayUrl: relayUrl,
+      token: token,
+      pubkey: pubkey,
+      nsec: nsec,
+    );
   }
 
   Future<void> save(StoredCredentials credentials) async {
@@ -37,11 +46,15 @@ class CredentialStorage {
     if (credentials.pubkey != null) {
       await _storage.write(key: _keyPubkey, value: credentials.pubkey);
     }
+    if (credentials.nsec != null) {
+      await _storage.write(key: _keyNsec, value: credentials.nsec);
+    }
   }
 
   Future<void> clear() async {
     await _storage.delete(key: _keyRelayUrl);
     await _storage.delete(key: _keyToken);
     await _storage.delete(key: _keyPubkey);
+    await _storage.delete(key: _keyNsec);
   }
 }
diff --git a/mobile/lib/shared/relay/app_lifecycle_provider.dart b/mobile/lib/shared/relay/app_lifecycle_provider.dart
new file mode 100644
index 00000000000..18e3eaebdf6
--- /dev/null
+++ b/mobile/lib/shared/relay/app_lifecycle_provider.dart
@@ -0,0 +1,55 @@
+import 'dart:async';
+
+import 'package:connectivity_plus/connectivity_plus.dart';
+import 'package:flutter/widgets.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import 'relay_session.dart';
+
+/// Tracks the app lifecycle state and drives websocket connect/disconnect
+/// behavior for mobile battery efficiency.
+class AppLifecycleNotifier extends Notifier<AppLifecycleState> {
+  AppLifecycleListener? _listener;
+  StreamSubscription<List<ConnectivityResult>>? _connectivitySub;
+
+  @override
+  AppLifecycleState build() {
+    _listener = AppLifecycleListener(onStateChange: _onStateChange);
+
+    // Watch connectivity changes to trigger reconnect on network restore.
+    _connectivitySub = Connectivity().onConnectivityChanged.listen((results) {
+      final hasNetwork = results.any((r) => r != ConnectivityResult.none);
+      if (hasNetwork && state == AppLifecycleState.resumed) {
+        ref.read(relaySessionProvider.notifier).onAppResumed();
+      }
+    });
+
+    ref.onDispose(() {
+      _listener?.dispose();
+      _connectivitySub?.cancel();
+    });
+
+    return AppLifecycleState.resumed;
+  }
+
+  void _onStateChange(AppLifecycleState newState) {
+    state = newState;
+
+    final session = ref.read(relaySessionProvider.notifier);
+    switch (newState) {
+      case AppLifecycleState.resumed:
+        session.onAppResumed();
+      case AppLifecycleState.paused:
+      case AppLifecycleState.detached:
+        session.onAppPaused();
+      case AppLifecycleState.inactive:
+      case AppLifecycleState.hidden:
+        break; // Brief transition states — no action.
+    }
+  }
+}
+
+final appLifecycleProvider =
+    NotifierProvider<AppLifecycleNotifier, AppLifecycleState>(
+      AppLifecycleNotifier.new,
+    );
diff --git a/mobile/lib/shared/relay/nostr_models.dart b/mobile/lib/shared/relay/nostr_models.dart
new file mode 100644
index 00000000000..ab501a6ebe0
--- /dev/null
+++ b/mobile/lib/shared/relay/nostr_models.dart
@@ -0,0 +1,138 @@
+import 'package:flutter/foundation.dart';
+
+/// Nostr event kind constants.
+///
+/// Keep in sync with `desktop/src/shared/constants/kinds.ts`.
+abstract final class EventKind {
+  static const deletion = 5;
+  static const reaction = 7;
+  static const streamMessage = 9;
+  static const typingIndicator = 20002;
+  static const auth = 22242;
+  static const streamMessageV2 = 40002;
+  static const streamMessageEdit = 40003;
+  static const streamMessageDiff = 40008;
+  static const systemMessage = 40099;
+  static const forumPost = 45001;
+  static const forumComment = 45003;
+
+  /// Event kinds that represent channel activity (messages, edits, reactions,
+  /// deletions, system events). Matches the desktop's `CHANNEL_EVENT_KINDS`.
+  static const channelEventKinds = [
+    deletion, // 5
+    reaction, // 7
+    streamMessage, // 9
+    40001, // legacy pre-migration stream messages
+    streamMessageEdit, // 40003
+    streamMessageDiff, // 40008
+    systemMessage, // 40099
+  ];
+}
+
+/// A Nostr event as defined by NIP-01.
+@immutable
+class NostrEvent {
+  final String id;
+  final String pubkey;
+  final int createdAt;
+  final int kind;
+  final List<List<String>> tags;
+  final String content;
+  final String sig;
+
+  const NostrEvent({
+    required this.id,
+    required this.pubkey,
+    required this.createdAt,
+    required this.kind,
+    required this.tags,
+    required this.content,
+    required this.sig,
+  });
+
+  factory NostrEvent.fromJson(Map<String, dynamic> json) {
+    return NostrEvent(
+      id: json['id'] as String,
+      pubkey: json['pubkey'] as String,
+      createdAt: json['created_at'] as int,
+      kind: json['kind'] as int,
+      tags: (json['tags'] as List<dynamic>)
+          .map((t) => (t as List<dynamic>).map((e) => e as String).toList())
+          .toList(),
+      content: json['content'] as String,
+      sig: json['sig'] as String,
+    );
+  }
+
+  Map<String, dynamic> toJson() => {
+    'id': id,
+    'pubkey': pubkey,
+    'created_at': createdAt,
+    'kind': kind,
+    'tags': tags,
+    'content': content,
+    'sig': sig,
+  };
+
+  /// Get the first value for a given tag key.
+  String? getTagValue(String key) {
+    for (final tag in tags) {
+      if (tag.isNotEmpty && tag[0] == key && tag.length > 1) {
+        return tag[1];
+      }
+    }
+    return null;
+  }
+
+  /// The channel/group ID from the `h` tag (NIP-29).
+  String? get channelId => getTagValue('h');
+
+  /// The parent event ID from the `e` tag.
+  String? get parentEventId => getTagValue('e');
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) || other is NostrEvent && id == other.id;
+
+  @override
+  int get hashCode => id.hashCode;
+}
+
+/// A NIP-01 subscription filter.
+@immutable
+class NostrFilter {
+  final List<int> kinds;
+  final int limit;
+  final int? since;
+  final int? until;
+
+  /// Tag filters, e.g. `{'#h': ['channel-id']}`.
+  final Map<String, List<String>> tags;
+
+  const NostrFilter({
+    required this.kinds,
+    this.limit = 100,
+    this.since,
+    this.until,
+    this.tags = const {},
+  });
+
+  /// Return a copy with an updated `since` value.
+  NostrFilter copyWithSince(int since) => NostrFilter(
+    kinds: kinds,
+    limit: limit,
+    since: since,
+    until: until,
+    tags: tags,
+  );
+
+  Map<String, dynamic> toJson() {
+    final json = <String, dynamic>{'kinds': kinds, 'limit': limit};
+    if (since != null) json['since'] = since;
+    if (until != null) json['until'] = until;
+    for (final entry in tags.entries) {
+      json[entry.key] = entry.value;
+    }
+    return json;
+  }
+}
diff --git a/mobile/lib/shared/relay/relay.dart b/mobile/lib/shared/relay/relay.dart
index 316474c29ad..d017071f1ff 100644
--- a/mobile/lib/shared/relay/relay.dart
+++ b/mobile/lib/shared/relay/relay.dart
@@ -1,2 +1,6 @@
+export 'app_lifecycle_provider.dart';
+export 'nostr_models.dart';
 export 'relay_client.dart';
 export 'relay_provider.dart';
+export 'relay_session.dart';
+export 'relay_socket.dart';
diff --git a/mobile/lib/shared/relay/relay_client.dart b/mobile/lib/shared/relay/relay_client.dart
index 7fa83ae85c1..a9b86b063c3 100644
--- a/mobile/lib/shared/relay/relay_client.dart
+++ b/mobile/lib/shared/relay/relay_client.dart
@@ -63,6 +63,19 @@ class RelayClient {
     return jsonDecode(response.body);
   }
 
+  /// POST [path] with a pre-encoded string body. Returns the raw response body.
+  Future<String> postRaw(String path, {required String body}) async {
+    final response = await _http.post(
+      _uri(path),
+      headers: _headers,
+      body: body,
+    );
+    if (response.statusCode < 200 || response.statusCode >= 300) {
+      throw RelayException(response.statusCode, response.body);
+    }
+    return response.body;
+  }
+
   void dispose() => _http.close();
 }
 
diff --git a/mobile/lib/shared/relay/relay_provider.dart b/mobile/lib/shared/relay/relay_provider.dart
index 7676ae3d709..fa1ff12713b 100644
--- a/mobile/lib/shared/relay/relay_provider.dart
+++ b/mobile/lib/shared/relay/relay_provider.dart
@@ -11,7 +11,22 @@ class RelayConfig {
   /// Used when the relay has `SPROUT_REQUIRE_AUTH_TOKEN=false`.
   final String? devPubkey;
 
-  const RelayConfig({required this.baseUrl, this.apiToken, this.devPubkey});
+  /// Nostr secret key (bech32 nsec) for signing NIP-42 AUTH events.
+  final String? nsec;
+
+  const RelayConfig({
+    required this.baseUrl,
+    this.apiToken,
+    this.devPubkey,
+    this.nsec,
+  });
+
+  /// Derive the websocket URL from the HTTP base URL.
+  String get wsUrl {
+    final uri = Uri.parse(baseUrl);
+    final scheme = uri.scheme == 'https' ? 'wss' : 'ws';
+    return uri.replace(scheme: scheme).toString();
+  }
 }
 
 /// Compile-time environment config via --dart-define.
@@ -44,11 +59,13 @@ class RelayConfigNotifier extends Notifier<RelayConfig> {
     required String baseUrl,
     required String? apiToken,
     required String? devPubkey,
+    String? nsec,
   }) {
     state = RelayConfig(
       baseUrl: baseUrl,
       apiToken: apiToken,
       devPubkey: devPubkey,
+      nsec: nsec,
     );
   }
 }
diff --git a/mobile/lib/shared/relay/relay_session.dart b/mobile/lib/shared/relay/relay_session.dart
new file mode 100644
index 00000000000..d3a5e786e70
--- /dev/null
+++ b/mobile/lib/shared/relay/relay_session.dart
@@ -0,0 +1,496 @@
+import 'dart:async';
+import 'dart:math';
+
+import 'package:flutter/widgets.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../auth/auth.dart';
+import 'nostr_models.dart';
+import 'relay_provider.dart';
+import 'relay_socket.dart';
+
+// ---------------------------------------------------------------------------
+// Session state
+// ---------------------------------------------------------------------------
+
+enum SessionStatus { disconnected, connecting, connected, reconnecting }
+
+@immutable
+class SessionState {
+  final SessionStatus status;
+  final int reconnectAttempt;
+
+  const SessionState({required this.status, this.reconnectAttempt = 0});
+}
+
+// ---------------------------------------------------------------------------
+// Internal subscription types
+// ---------------------------------------------------------------------------
+
+class _HistorySubscription {
+  final List<NostrEvent> events = [];
+  final Completer<List<NostrEvent>> completer;
+  final Timer timeout;
+
+  _HistorySubscription({required this.completer, required this.timeout});
+}
+
+class _LiveSubscription {
+  final NostrFilter filter;
+  final void Function(NostrEvent) onEvent;
+  Completer<void>? readyCompleter;
+  int? lastSeenCreatedAt;
+
+  _LiveSubscription({
+    required this.filter,
+    required this.onEvent,
+    this.readyCompleter,
+  });
+}
+
+class _PendingEvent {
+  final Completer<NostrEvent> completer;
+  final Timer timeout;
+
+  _PendingEvent({required this.completer, required this.timeout});
+}
+
+class _BufferedEvent {
+  final String subId;
+  final NostrEvent event;
+
+  _BufferedEvent(this.subId, this.event);
+}
+
+// ---------------------------------------------------------------------------
+// RelaySession — the core session manager
+// ---------------------------------------------------------------------------
+
+/// Manages websocket subscriptions, event batching, reconnection with replay,
+/// and pending event tracking. Equivalent to the desktop's RelayClientSession.
+class RelaySessionNotifier extends Notifier<SessionState> {
+  static const _baseReconnectDelayMs = 1000;
+  static const _maxReconnectDelayMs = 30000;
+  static const _eventBatchMs = 16;
+  static const _reconnectReplaySkewSeconds = 5;
+
+  RelaySocket? _socket;
+  final Map<String, _HistorySubscription> _historySubscriptions = {};
+  final Map<String, _LiveSubscription> _liveSubscriptions = {};
+  final Map<String, _PendingEvent> _pendingEvents = {};
+  final List<_BufferedEvent> _eventBuffer = [];
+  final Set<String> _recentEventIds = {};
+  Timer? _reconnectTimer;
+  Timer? _flushTimer;
+  Timer? _backgroundGraceTimer;
+  int _reconnectDelayMs = _baseReconnectDelayMs;
+  int _subIdCounter = 0;
+  bool _disposed = false;
+
+  @override
+  SessionState build() {
+    final config = ref.watch(relayConfigProvider);
+    final authState = ref.watch(authProvider);
+
+    ref.onDispose(_dispose);
+
+    // Auto-connect when authenticated and we have credentials.
+    final isAuthenticated = authState.value?.status == AuthStatus.authenticated;
+    if (isAuthenticated && config.apiToken != null) {
+      // Schedule connection after build completes.
+      Future.microtask(() => _connect(config));
+    }
+
+    return const SessionState(status: SessionStatus.disconnected);
+  }
+
+  // -------------------------------------------------------------------------
+  // Public API
+  // -------------------------------------------------------------------------
+
+  /// Fetch historical events matching [filter]. Sends REQ, collects events
+  /// until EOSE, then resolves. One-shot subscription.
+  Future<List<NostrEvent>> fetchHistory(
+    NostrFilter filter, {
+    Duration timeout = const Duration(seconds: 8),
+  }) {
+    final subId = _nextSubId('h');
+    final completer = Completer<List<NostrEvent>>();
+
+    final timer = Timer(timeout, () {
+      final sub = _historySubscriptions.remove(subId);
+      if (sub != null && !sub.completer.isCompleted) {
+        // Resolve with whatever we collected so far rather than failing.
+        sub.completer.complete(sub.events);
+      }
+      _sendClose(subId);
+    });
+
+    _historySubscriptions[subId] = _HistorySubscription(
+      completer: completer,
+      timeout: timer,
+    );
+
+    _sendReq(subId, filter);
+    return completer.future;
+  }
+
+  /// Subscribe to live events matching [filter]. Returns an unsubscribe
+  /// function. Live subscriptions survive reconnects — they are replayed with
+  /// `since: lastSeenCreatedAt - 5s` on reconnect.
+  Future<void Function()> subscribe(
+    NostrFilter filter,
+    void Function(NostrEvent) onEvent,
+  ) async {
+    final subId = _nextSubId('l');
+    final readyCompleter = Completer<void>();
+
+    _liveSubscriptions[subId] = _LiveSubscription(
+      filter: filter,
+      onEvent: onEvent,
+      readyCompleter: readyCompleter,
+    );
+
+    _sendReq(subId, filter);
+
+    // Wait for EOSE or a short fallback timeout.
+    await readyCompleter.future.timeout(
+      const Duration(milliseconds: 500),
+      onTimeout: () {},
+    );
+
+    return () => _unsubscribe(subId);
+  }
+
+  /// Publish an event and wait for the relay's OK confirmation.
+  Future<NostrEvent> publish(
+    NostrEvent event, {
+    Duration timeout = const Duration(seconds: 8),
+  }) {
+    final completer = Completer<NostrEvent>();
+
+    final timer = Timer(timeout, () {
+      final pending = _pendingEvents.remove(event.id);
+      if (pending != null && !pending.completer.isCompleted) {
+        pending.completer.completeError(
+          TimeoutException(
+            'Event ${event.id} not acknowledged within $timeout',
+          ),
+        );
+      }
+    });
+
+    _pendingEvents[event.id] = _PendingEvent(
+      completer: completer,
+      timeout: timer,
+    );
+
+    _socket?.send(['EVENT', event.toJson()]);
+    return completer.future;
+  }
+
+  /// Force a reconnect (e.g., returning from background).
+  Future<void> reconnect() async {
+    await _socket?.disconnect();
+    _reconnectDelayMs = _baseReconnectDelayMs;
+    final config = ref.read(relayConfigProvider);
+    await _connect(config);
+  }
+
+  /// Called by the app lifecycle provider when the app goes to background.
+  void onAppPaused() {
+    _backgroundGraceTimer?.cancel();
+    _backgroundGraceTimer = Timer(const Duration(seconds: 30), () {
+      _socket?.disconnect();
+      state = const SessionState(status: SessionStatus.disconnected);
+    });
+  }
+
+  /// Called by the app lifecycle provider when the app returns to foreground.
+  void onAppResumed() {
+    _backgroundGraceTimer?.cancel();
+    _backgroundGraceTimer = null;
+    if (state.status == SessionStatus.disconnected) {
+      _reconnectDelayMs = _baseReconnectDelayMs;
+      final config = ref.read(relayConfigProvider);
+      _connect(config);
+    }
+  }
+
+  // -------------------------------------------------------------------------
+  // Connection management
+  // -------------------------------------------------------------------------
+
+  Future<void> _connect(RelayConfig config) async {
+    if (_disposed) return;
+    if (_socket?.state == SocketState.connecting ||
+        _socket?.state == SocketState.authenticating) {
+      return;
+    }
+
+    state = SessionState(
+      status: SessionStatus.connecting,
+      reconnectAttempt: state.reconnectAttempt,
+    );
+
+    _socket?.dispose();
+    _socket = RelaySocket(
+      wsUrl: config.wsUrl,
+      nsec: config.nsec,
+      apiToken: config.apiToken,
+      onMessage: _handleMessage,
+      onConnected: _handleConnected,
+      onDisconnected: _handleDisconnected,
+    );
+
+    await _socket!.connect();
+  }
+
+  void _handleConnected() {
+    if (_disposed) return;
+    _reconnectDelayMs = _baseReconnectDelayMs;
+    state = const SessionState(status: SessionStatus.connected);
+    _replayLiveSubscriptions();
+  }
+
+  void _handleDisconnected(Object? error) {
+    if (_disposed) return;
+    _cancelAllHistory(error);
+    _rejectAllPending(error);
+    _eventBuffer.clear();
+    _flushTimer?.cancel();
+    _flushTimer = null;
+    _scheduleReconnect();
+  }
+
+  void _scheduleReconnect() {
+    if (_disposed) return;
+    if (_liveSubscriptions.isEmpty) {
+      state = const SessionState(status: SessionStatus.disconnected);
+      return;
+    }
+
+    final attempt = state.reconnectAttempt + 1;
+    state = SessionState(
+      status: SessionStatus.reconnecting,
+      reconnectAttempt: attempt,
+    );
+
+    _reconnectTimer?.cancel();
+    _reconnectTimer = Timer(Duration(milliseconds: _reconnectDelayMs), () {
+      _reconnectDelayMs = min(_reconnectDelayMs * 2, _maxReconnectDelayMs);
+      final config = ref.read(relayConfigProvider);
+      _connect(config);
+    });
+  }
+
+  /// Replay all live subscriptions after a reconnect, with a time skew to
+  /// catch events that occurred during the disconnect.
+  void _replayLiveSubscriptions() {
+    for (final entry in _liveSubscriptions.entries) {
+      final sub = entry.value;
+      final since = sub.lastSeenCreatedAt != null
+          ? sub.lastSeenCreatedAt! - _reconnectReplaySkewSeconds
+          : null;
+      final filter = since != null
+          ? sub.filter.copyWithSince(since)
+          : sub.filter;
+      _sendReq(entry.key, filter);
+    }
+  }
+
+  // -------------------------------------------------------------------------
+  // Message dispatch
+  // -------------------------------------------------------------------------
+
+  void _handleMessage(List<dynamic> data) {
+    if (data.isEmpty) return;
+    final type = data[0] as String;
+
+    switch (type) {
+      case 'EVENT':
+        _handleEvent(data);
+      case 'EOSE':
+        _handleEose(data);
+      case 'OK':
+        _handleOk(data);
+    }
+  }
+
+  void _handleEvent(List<dynamic> data) {
+    if (data.length < 3) return;
+    final subId = data[1] as String;
+    final eventJson = data[2] as Map<String, dynamic>;
+    final event = NostrEvent.fromJson(eventJson);
+
+    // History subscriptions accumulate immediately.
+    final historySub = _historySubscriptions[subId];
+    if (historySub != null) {
+      historySub.events.add(event);
+      return;
+    }
+
+    // Live subscriptions get batched.
+    final liveSub = _liveSubscriptions[subId];
+    if (liveSub != null) {
+      // Track last seen timestamp for reconnect replay.
+      if (liveSub.lastSeenCreatedAt == null ||
+          event.createdAt > liveSub.lastSeenCreatedAt!) {
+        liveSub.lastSeenCreatedAt = event.createdAt;
+      }
+      _eventBuffer.add(_BufferedEvent(subId, event));
+      _scheduleFlush();
+    }
+  }
+
+  void _handleEose(List<dynamic> data) {
+    if (data.length < 2) return;
+    final subId = data[1] as String;
+
+    // History subscription: resolve with collected events.
+    final historySub = _historySubscriptions.remove(subId);
+    if (historySub != null) {
+      historySub.timeout.cancel();
+      if (!historySub.completer.isCompleted) {
+        historySub.completer.complete(historySub.events);
+      }
+      _sendClose(subId);
+      return;
+    }
+
+    // Live subscription: signal ready.
+    final liveSub = _liveSubscriptions[subId];
+    if (liveSub != null &&
+        liveSub.readyCompleter != null &&
+        !liveSub.readyCompleter!.isCompleted) {
+      liveSub.readyCompleter!.complete();
+      liveSub.readyCompleter = null;
+    }
+  }
+
+  void _handleOk(List<dynamic> data) {
+    if (data.length < 3) return;
+    final eventId = data[1] as String;
+    final accepted = data[2] as bool;
+
+    final pending = _pendingEvents.remove(eventId);
+    if (pending == null) return;
+    pending.timeout.cancel();
+
+    if (accepted) {
+      // We don't have the full event here; create a minimal placeholder.
+      // The caller typically already has the event they published.
+      if (!pending.completer.isCompleted) {
+        pending.completer.complete(
+          NostrEvent(
+            id: eventId,
+            pubkey: '',
+            createdAt: 0,
+            kind: 0,
+            tags: [],
+            content: '',
+            sig: '',
+          ),
+        );
+      }
+    } else {
+      final message = data.length > 3 ? data[3] as String : 'Event rejected';
+      if (!pending.completer.isCompleted) {
+        pending.completer.completeError(Exception(message));
+      }
+    }
+  }
+
+  // -------------------------------------------------------------------------
+  // Event batching (16ms flush interval)
+  // -------------------------------------------------------------------------
+
+  void _scheduleFlush() {
+    _flushTimer ??= Timer(
+      const Duration(milliseconds: _eventBatchMs),
+      _flushEventBuffer,
+    );
+  }
+
+  void _flushEventBuffer() {
+    _flushTimer = null;
+    if (_eventBuffer.isEmpty) return;
+
+    final batch = List<_BufferedEvent>.from(_eventBuffer);
+    _eventBuffer.clear();
+
+    for (final buffered in batch) {
+      // Deduplication: skip events we've already seen recently.
+      if (_recentEventIds.contains(buffered.event.id)) continue;
+      _recentEventIds.add(buffered.event.id);
+
+      // Cap the dedup set to prevent unbounded memory growth.
+      if (_recentEventIds.length > 5000) {
+        _recentEventIds.clear();
+      }
+
+      final sub = _liveSubscriptions[buffered.subId];
+      if (sub != null) {
+        sub.onEvent(buffered.event);
+      }
+    }
+  }
+
+  // -------------------------------------------------------------------------
+  // Helpers
+  // -------------------------------------------------------------------------
+
+  String _nextSubId(String prefix) {
+    _subIdCounter++;
+    return '$prefix-$_subIdCounter';
+  }
+
+  void _sendReq(String subId, NostrFilter filter) {
+    _socket?.send(['REQ', subId, filter.toJson()]);
+  }
+
+  void _sendClose(String subId) {
+    _socket?.send(['CLOSE', subId]);
+  }
+
+  void _unsubscribe(String subId) {
+    _liveSubscriptions.remove(subId);
+    _sendClose(subId);
+  }
+
+  void _cancelAllHistory(Object? error) {
+    for (final entry in _historySubscriptions.values) {
+      entry.timeout.cancel();
+      if (!entry.completer.isCompleted) {
+        entry.completer.completeError(error ?? Exception('Connection lost'));
+      }
+    }
+    _historySubscriptions.clear();
+  }
+
+  void _rejectAllPending(Object? error) {
+    for (final entry in _pendingEvents.values) {
+      entry.timeout.cancel();
+      if (!entry.completer.isCompleted) {
+        entry.completer.completeError(error ?? Exception('Connection lost'));
+      }
+    }
+    _pendingEvents.clear();
+  }
+
+  void _dispose() {
+    _disposed = true;
+    _reconnectTimer?.cancel();
+    _flushTimer?.cancel();
+    _backgroundGraceTimer?.cancel();
+    _cancelAllHistory(null);
+    _rejectAllPending(null);
+    _socket?.dispose();
+    _socket = null;
+  }
+}
+
+final relaySessionProvider =
+    NotifierProvider<RelaySessionNotifier, SessionState>(
+      RelaySessionNotifier.new,
+    );
diff --git a/mobile/lib/shared/relay/relay_socket.dart b/mobile/lib/shared/relay/relay_socket.dart
new file mode 100644
index 00000000000..ecf2b7afa44
--- /dev/null
+++ b/mobile/lib/shared/relay/relay_socket.dart
@@ -0,0 +1,230 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:nostr/nostr.dart' as nostr;
+import 'package:web_socket_channel/web_socket_channel.dart';
+
+import 'nostr_models.dart';
+
+/// Low-level websocket connection with NIP-42 authentication.
+///
+/// Handles the raw websocket lifecycle: connect, authenticate via NIP-42
+/// challenge/response, send/receive JSON frames, and disconnect.
+///
+/// Does NOT handle reconnection — that is [RelaySessionNotifier]'s job.
+enum SocketState { disconnected, connecting, authenticating, connected }
+
+class RelaySocket {
+  final String _wsUrl;
+  final String? _nsec;
+  final String? _apiToken;
+  final void Function(List<dynamic> message) _onMessage;
+  final void Function() _onConnected;
+  final void Function(Object? error) _onDisconnected;
+
+  WebSocketChannel? _channel;
+  StreamSubscription<dynamic>? _subscription;
+  SocketState _state = SocketState.disconnected;
+  Completer<void>? _authCompleter;
+  Timer? _authTimeout;
+  String? _pendingAuthEventId;
+
+  SocketState get state => _state;
+
+  RelaySocket({
+    required String wsUrl,
+    required String? nsec,
+    required String? apiToken,
+    required void Function(List<dynamic> message) onMessage,
+    required void Function() onConnected,
+    required void Function(Object? error) onDisconnected,
+  }) : _wsUrl = wsUrl,
+       _nsec = nsec,
+       _apiToken = apiToken,
+       _onMessage = onMessage,
+       _onConnected = onConnected,
+       _onDisconnected = onDisconnected;
+
+  /// Connect to the relay and complete NIP-42 authentication.
+  Future<void> connect() async {
+    if (_state != SocketState.disconnected) return;
+    _state = SocketState.connecting;
+
+    try {
+      _channel = WebSocketChannel.connect(Uri.parse(_wsUrl));
+      await _channel!.ready;
+    } catch (e) {
+      _state = SocketState.disconnected;
+      _onDisconnected(e);
+      return;
+    }
+
+    _state = SocketState.authenticating;
+    _authCompleter = Completer<void>();
+
+    _subscription = _channel!.stream.listen(
+      _handleRawMessage,
+      onError: (Object error) {
+        _failAuth(error);
+        _resetConnection();
+        _onDisconnected(error);
+      },
+      onDone: () {
+        _failAuth(null);
+        _resetConnection();
+        _onDisconnected(null);
+      },
+    );
+
+    // Wait for auth to complete (or timeout).
+    _authTimeout = Timer(const Duration(seconds: 8), () {
+      if (_authCompleter != null && !_authCompleter!.isCompleted) {
+        _authCompleter!.completeError(
+          TimeoutException('NIP-42 auth timed out after 8s'),
+        );
+      }
+    });
+
+    try {
+      await _authCompleter!.future;
+      _authTimeout?.cancel();
+      _state = SocketState.connected;
+      _onConnected();
+    } catch (e) {
+      _authTimeout?.cancel();
+      await disconnect();
+      _onDisconnected(e);
+    }
+  }
+
+  /// Send a raw JSON array over the websocket.
+  void send(List<dynamic> payload) {
+    _channel?.sink.add(jsonEncode(payload));
+  }
+
+  /// Gracefully close the connection.
+  Future<void> disconnect() async {
+    _resetConnection();
+    final channel = _channel;
+    _channel = null;
+    if (channel != null) {
+      await channel.sink.close();
+    }
+  }
+
+  void dispose() {
+    _resetConnection();
+    _channel?.sink.close();
+    _channel = null;
+  }
+
+  void _resetConnection() {
+    _state = SocketState.disconnected;
+    _subscription?.cancel();
+    _subscription = null;
+    _authTimeout?.cancel();
+    _authTimeout = null;
+    _pendingAuthEventId = null;
+  }
+
+  void _failAuth(Object? error) {
+    if (_authCompleter != null && !_authCompleter!.isCompleted) {
+      _authCompleter!.completeError(error ?? Exception('Connection closed'));
+    }
+  }
+
+  void _handleRawMessage(dynamic raw) {
+    final String text;
+    if (raw is String) {
+      text = raw;
+    } else {
+      return; // Binary frames are not part of the Nostr protocol.
+    }
+
+    final List<dynamic> data;
+    try {
+      data = jsonDecode(text) as List<dynamic>;
+    } catch (_) {
+      return; // Malformed JSON.
+    }
+
+    if (data.isEmpty) return;
+    final type = data[0] as String;
+
+    switch (type) {
+      case 'AUTH':
+        _handleAuthChallenge(data);
+      case 'OK':
+        _handleOk(data);
+      default:
+        // Pass EVENT, EOSE, NOTICE, etc. upstream.
+        _onMessage(data);
+    }
+  }
+
+  /// Handle the relay's AUTH challenge: sign a kind:22242 event and respond.
+  void _handleAuthChallenge(List<dynamic> data) {
+    if (data.length < 2) return;
+    final challenge = data[1] as String;
+
+    if (_nsec == null) {
+      _failAuth(Exception('No nsec available for NIP-42 auth'));
+      return;
+    }
+
+    try {
+      // Decode bech32 nsec to hex private key.
+      final privkeyHex = nostr.Nip19.decodePrivkey(_nsec);
+      if (privkeyHex.isEmpty) {
+        _failAuth(Exception('Invalid nsec'));
+        return;
+      }
+
+      // Build the auth tags.
+      final tags = <List<String>>[
+        ['relay', _wsUrl],
+        ['challenge', challenge],
+        if (_apiToken != null) ['auth_token', _apiToken],
+      ];
+
+      // Create and sign the kind:22242 AUTH event.
+      final event = nostr.Event.from(
+        kind: EventKind.auth,
+        content: '',
+        tags: tags,
+        privkey: privkeyHex,
+      );
+
+      _pendingAuthEventId = event.id;
+      send(['AUTH', event.toJson()]);
+    } catch (e) {
+      _failAuth(e);
+    }
+  }
+
+  /// Handle OK frames. During auth, complete the auth flow.
+  void _handleOk(List<dynamic> data) {
+    if (data.length < 3) return;
+    final eventId = data[1] as String;
+    final accepted = data[2] as bool;
+
+    // Check if this OK is for our pending AUTH event.
+    if (_pendingAuthEventId != null && eventId == _pendingAuthEventId) {
+      _pendingAuthEventId = null;
+      if (accepted) {
+        if (_authCompleter != null && !_authCompleter!.isCompleted) {
+          _authCompleter!.complete();
+        }
+      } else {
+        final message = data.length > 3
+            ? data[3] as String
+            : 'Auth rejected by relay';
+        _failAuth(Exception(message));
+      }
+      return;
+    }
+
+    // Pass non-auth OK frames upstream for pending event tracking.
+    _onMessage(data);
+  }
+}
diff --git a/mobile/pubspec.lock b/mobile/pubspec.lock
index d3bd84cda52..b2614f634be 100644
--- a/mobile/pubspec.lock
+++ b/mobile/pubspec.lock
@@ -57,6 +57,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.13.1"
+  bech32:
+    dependency: transitive
+    description:
+      name: bech32
+      sha256: "156cbace936f7720c79a79d16a03efad343b1ef17106716e04b8b8e39f99f7f7"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.2"
+  bip340:
+    dependency: transitive
+    description:
+      name: bip340
+      sha256: "2a92f6ed68959f75d67c9a304c17928b9c9449587d4f75ee68f34152f7f69e87"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.2.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -137,6 +153,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.19.1"
+  connectivity_plus:
+    dependency: "direct main"
+    description:
+      name: connectivity_plus
+      sha256: b5e72753cf63becce2c61fd04dfe0f1c430cc5278b53a1342dc5ad839eab29ec
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.1.5"
+  connectivity_plus_platform_interface:
+    dependency: transitive
+    description:
+      name: connectivity_plus_platform_interface
+      sha256: "3c09627c536d22fd24691a905cdd8b14520de69da52c7a97499c8be5284a32ed"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.1.0"
   convert:
     dependency: transitive
     description:
@@ -193,6 +225,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "3.1.3"
+  dbus:
+    dependency: transitive
+    description:
+      name: dbus
+      sha256: d0c98dcd4f5169878b6cf8f6e0a52403a9dff371a3e2f019697accbf6f44a270
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.12"
   fake_async:
     dependency: transitive
     description:
@@ -520,6 +560,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.17.6"
+  nm:
+    dependency: transitive
+    description:
+      name: nm
+      sha256: "2c9aae4127bdc8993206464fcc063611e0e36e72018696cd9631023a31b24254"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.5.0"
   node_preamble:
     dependency: transitive
     description:
@@ -528,6 +576,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.2"
+  nostr:
+    dependency: "direct main"
+    description:
+      name: nostr
+      sha256: a99942e4eedd5823d16f42e6df96240488028666a329ee1047552f79db564123
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.5.0"
   objective_c:
     dependency: transitive
     description:
@@ -600,6 +656,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.3.0"
+  petitparser:
+    dependency: transitive
+    description:
+      name: petitparser
+      sha256: "91bd59303e9f769f108f8df05e371341b15d59e995e6806aefab827b58336675"
+      url: "https://pub.dev"
+    source: hosted
+    version: "7.0.2"
   platform:
     dependency: transitive
     description:
@@ -616,6 +680,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.1.8"
+  pointycastle:
+    dependency: transitive
+    description:
+      name: pointycastle
+      sha256: "4be0097fcf3fd3e8449e53730c631200ebc7b88016acecab2b0da2f0149222fe"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.9.1"
   pool:
     dependency: transitive
     description:
@@ -918,7 +990,7 @@ packages:
     source: hosted
     version: "1.0.1"
   web_socket_channel:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: web_socket_channel
       sha256: d645757fb0f4773d602444000a8131ff5d48c9e47adfe9772652dd1a4f2d45c8
@@ -949,6 +1021,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.1.0"
+  xml:
+    dependency: transitive
+    description:
+      name: xml
+      sha256: "971043b3a0d3da28727e40ed3e0b5d18b742fa5a68665cca88e74b7876d5e025"
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.6.1"
   yaml:
     dependency: transitive
     description:
diff --git a/mobile/pubspec.yaml b/mobile/pubspec.yaml
index 2704af93baf..7bcfb52620f 100644
--- a/mobile/pubspec.yaml
+++ b/mobile/pubspec.yaml
@@ -16,6 +16,9 @@ dependencies:
   flutter_secure_storage: ^9.2.4
   mobile_scanner: ^6.0.2
   shared_preferences: ^2.5.5
+  web_socket_channel: ^3.0.1
+  connectivity_plus: ^6.1.4
+  nostr: ^1.5.0
 
 dev_dependencies:
   flutter_test: