diff --git a/flutter/Makefile b/flutter/Makefile
index de96c3d..da51fdf 100644
--- a/flutter/Makefile
+++ b/flutter/Makefile
@@ -4,6 +4,8 @@ run:
 	dart run build_runner build
 	flutter run
 	
+test:
+	dart analyze
 
 gen:
 	dart run build_runner build
diff --git a/flutter/analysis_options.yaml b/flutter/analysis_options.yaml
index 64222f2..8eac293 100644
--- a/flutter/analysis_options.yaml
+++ b/flutter/analysis_options.yaml
@@ -1,29 +1,117 @@
-# This file configures the analyzer, which statically analyzes Dart code to
-# check for errors, warnings, and lints.
-#
-# The issues identified by the analyzer are surfaced in the UI of Dart-enabled
-# IDEs (https://dart.dev/tools#ides-and-editors). The analyzer can also be
-# invoked from the command line by running `flutter analyze`.
 
-# The following line activates a set of recommended lints for Flutter apps,
-# packages, and plugins designed to encourage good coding practices.
-include: package:flutter_lints/flutter.yaml
+include: 
+ - package:lints/recommended.yaml
+ - package:flutter_lints/flutter.yaml
 
 linter:
-  # The lint rules applied to this project can be customized in the
-  # section below to disable rules from the `package:flutter_lints/flutter.yaml`
-  # included above or to enable additional rules. A list of all available lints
-  # and their documentation is published at https://dart.dev/lints.
-  #
-  # Instead of disabling a lint rule for the entire project in the
-  # section below, it can also be suppressed for a single line of code
-  # or a specific dart file by using the `// ignore: name_of_lint` and
-  # `// ignore_for_file: name_of_lint` syntax on the line or in the file
-  # producing the lint.
+  
+  
   rules:
-    # avoid_print: false  # Uncomment to disable the `avoid_print` rule
-    # prefer_single_quotes: true  # Uncomment to enable the `prefer_single_quotes` rule
-    prefer_relative_imports: true,
+    always_use_package_imports: true,
+    avoid_empty_else: true,
+    avoid_returning_null_for_future: true,
+    avoid_type_to_string: true,
+    avoid_types_as_parameter_names: true,
+    avoid_web_libraries_in_flutter: true,
+    collection_methods_unrelated_type: true,
+    discarded_futures: true,
+    empty_statements: true,
+    hash_and_equals: true,
+    implicit_reopen: true,
+    invalid_case_patterns: true,
+    invariant_booleans: true,
+    no_duplicate_case_values: true,
+    no_logic_in_create_state: true,
+    no_self_assignments: true,
+    no_wildcard_variable_uses: true,
+    prefer_void_to_null: true,
+    unnecessary_statements: true,
+    valid_regexps: true,
+    always_declare_return_types: true,
+    always_put_control_body_on_new_line: true,
+    always_specify_types: true,
+    annotate_overrides: true,
+    annotate_redeclares: true,
+    avoid_annotating_with_dynamic: true,
+    avoid_function_literals_in_foreach_calls: true,
+    avoid_init_to_null: true,
+    avoid_null_checks_in_equality_operators: true,
+    avoid_renaming_method_parameters: true,
+    avoid_return_types_on_setters: true,
+    avoid_returning_null: true,
+    avoid_returning_null_for_void: true,
+    avoid_returning_this: true,
+    avoid_shadowing_type_parameters: true,
+    avoid_single_cascade_in_expression_statements: true,
+    avoid_unnecessary_containers: true,
+    avoid_unused_constructor_parameters: true,
+    avoid_void_async: true,
+    await_only_futures: true,
+    camel_case_extensions: true,
+    camel_case_types: true,
+    cast_nullable_to_non_nullable: true,
+    constant_identifier_names: true,
+    empty_catches: true,
+    eol_at_end_of_file: true,
+    exhaustive_cases: true,
+    file_names: true,
+    no_literal_bool_comparisons: true,
+    null_check_on_nullable_type_parameter: true,
+    null_closures: true,
+    overridden_fields: true,
+    prefer_adjacent_string_concatenation: true,
+    prefer_collection_literals: true,
+    prefer_conditional_assignment: true,
+    prefer_const_constructors: true,
+    prefer_const_constructors_in_immutables: true,
+    prefer_const_declarations: true,
+    prefer_const_literals_to_create_immutables: true,
+    prefer_contains: true,
+    prefer_final_fields: true,
+    prefer_for_elements_to_map_fromIterable: true,
+    prefer_function_declarations_over_variables: true,
+    prefer_generic_function_type_aliases: true,
+    prefer_if_null_operators: true,
+    prefer_initializing_formals: true,
+    prefer_inlined_adds: true,
+    prefer_interpolation_to_compose_strings: true,
+    prefer_is_empty: true,
+    prefer_is_not_empty: true,
+    prefer_is_not_operator: true,
+    prefer_iterable_whereType: true,
+    prefer_null_aware_operators: true,
+    prefer_spread_collections: true,
+    prefer_typing_uninitialized_variables: true,
+    provide_deprecation_message: true,
+    recursive_getters: true,
+    sized_box_for_whitespace: true,
+    type_init_formals: true,
+    type_literal_in_constant_pattern: true,
+    unnecessary_const: true,
+    unnecessary_constructor_name: true,
+    unnecessary_getters_setters: true,
+    unnecessary_late: true,
+    unnecessary_new: true,
+    unnecessary_null_aware_assignments: true,
+    unnecessary_null_in_if_null_operators: true,
+    unnecessary_nullable_for_final_variable_declarations: true,
+    unnecessary_overrides: true,
+    unnecessary_string_escapes: true,
+    unnecessary_string_interpolations: true,
+    unnecessary_this: true,
+    unnecessary_to_list_in_spreads: true,
+    use_full_hex_values_for_flutter_colors: true,
+    use_function_type_syntax_for_parameters: true,
+    use_rethrow_when_possible: true,
+    use_string_in_part_of_directives: true,
+    use_super_parameters: true,
+    void_checks: true,
+    depend_on_referenced_packages: true,
+    package_names: true,
+    secure_pubspec_urls: true,
     
-# Additional information about this file can be found at
-# https://dart.dev/guides/language/analysis-options
+analyzer:
+  language:
+    strict-casts: true
+    strict-inference: true
+    strict-raw-types: true
\ No newline at end of file
diff --git a/flutter/lib/api/api_client.dart b/flutter/lib/api/api_client.dart
index 47ea5da..d02174e 100644
--- a/flutter/lib/api/api_client.dart
+++ b/flutter/lib/api/api_client.dart
@@ -74,7 +74,7 @@ class APIClient {
 
     if (responseStatusCode != 200) {
       try {
-        final apierr = APIError.fromJson(jsonDecode(responseBody));
+        final apierr = APIError.fromJson(jsonDecode(responseBody) as Map<String, dynamic>);
 
         RequestLog.addRequestAPIError(name, t0, method, uri, req.body, req.headers, responseStatusCode, responseBody, responseHeaders, apierr);
         showPlatformToast(child: Text('Request "${name}" is fehlgeschlagen'), context: ToastProvider.context);
@@ -90,7 +90,7 @@ class APIClient {
       final data = jsonDecode(responseBody);
 
       if (fn != null) {
-        final result = fn(data);
+        final result = fn(data as Map<String, dynamic>);
         RequestLog.addRequestSuccess(name, t0, method, uri, req.body, req.headers, responseStatusCode, responseBody, responseHeaders);
         return result;
       } else {
@@ -137,7 +137,7 @@ class APIClient {
       method: 'GET',
       relURL: 'users/${auth.userId}/channels',
       query: {'selector': sel.apiKey},
-      fn: (json) => ChannelWithSubscription.fromJsonArray(json['channels']),
+      fn: (json) => ChannelWithSubscription.fromJsonArray(json['channels'] as List<dynamic>),
       auth: auth,
     );
   }
diff --git a/flutter/lib/components/layout/app_bar.dart b/flutter/lib/components/layout/app_bar.dart
index b690ae6..4c3218f 100644
--- a/flutter/lib/components/layout/app_bar.dart
+++ b/flutter/lib/components/layout/app_bar.dart
@@ -39,7 +39,7 @@ class SCNAppBar extends StatelessWidget implements PreferredSizeWidget {
             icon: const Icon(FontAwesomeIcons.solidSpiderBlackWidow),
             tooltip: 'Debug',
             onPressed: () {
-              Navigator.push(context, MaterialPageRoute(builder: (context) => DebugMainPage()));
+              Navigator.push(context, MaterialPageRoute<DebugMainPage>(builder: (context) => DebugMainPage()));
             },
           ),
         if (!showDebug) SizedBox.square(dimension: 40),
diff --git a/flutter/lib/models/api_error.dart b/flutter/lib/models/api_error.dart
index 374d712..adb6fb2 100644
--- a/flutter/lib/models/api_error.dart
+++ b/flutter/lib/models/api_error.dart
@@ -13,10 +13,10 @@ class APIError {
 
   factory APIError.fromJson(Map<String, dynamic> json) {
     return APIError(
-      success: json['success'],
-      error: json['error'],
-      errhighlight: json['errhighlight'],
-      message: json['message'],
+      success: json['success'] as String,
+      error: json['error'] as String,
+      errhighlight: json['errhighlight'] as String,
+      message: json['message'] as String,
     );
   }
 }
diff --git a/flutter/lib/models/channel.dart b/flutter/lib/models/channel.dart
index e92dad3..337e19d 100644
--- a/flutter/lib/models/channel.dart
+++ b/flutter/lib/models/channel.dart
@@ -25,15 +25,15 @@ class Channel {
 
   factory Channel.fromJson(Map<String, dynamic> json) {
     return Channel(
-      channelID: json['channel_id'],
-      ownerUserID: json['owner_user_id'],
-      internalName: json['internal_name'],
-      displayName: json['display_name'],
-      descriptionName: json['description_name'],
-      subscribeKey: json['subscribe_key'],
-      timestampCreated: json['timestamp_created'],
-      timestampLastSent: json['timestamp_lastsent'],
-      messagesSent: json['messages_sent'],
+      channelID: json['channel_id'] as String,
+      ownerUserID: json['owner_user_id'] as String,
+      internalName: json['internal_name'] as String,
+      displayName: json['display_name'] as String,
+      descriptionName: json['description_name'] as String?,
+      subscribeKey: json['subscribe_key'] as String?,
+      timestampCreated: json['timestamp_created'] as String,
+      timestampLastSent: json['timestamp_lastsent'] as String?,
+      messagesSent: json['messages_sent'] as int,
     );
   }
 }
@@ -56,20 +56,20 @@ class ChannelWithSubscription extends Channel {
 
   factory ChannelWithSubscription.fromJson(Map<String, dynamic> json) {
     return ChannelWithSubscription(
-      channelID: json['channel_id'],
-      ownerUserID: json['owner_user_id'],
-      internalName: json['internal_name'],
-      displayName: json['display_name'],
-      descriptionName: json['description_name'],
-      subscribeKey: json['subscribe_key'],
-      timestampCreated: json['timestamp_created'],
-      timestampLastSent: json['timestamp_lastsent'],
-      messagesSent: json['messages_sent'],
-      subscription: Subscription.fromJson(json['subscription']),
+      channelID: json['channel_id'] as String,
+      ownerUserID: json['owner_user_id'] as String,
+      internalName: json['internal_name'] as String,
+      displayName: json['display_name'] as String,
+      descriptionName: json['description_name'] as String?,
+      subscribeKey: json['subscribe_key'] as String?,
+      timestampCreated: json['timestamp_created'] as String,
+      timestampLastSent: json['timestamp_lastsent'] as String?,
+      messagesSent: json['messages_sent'] as int,
+      subscription: Subscription.fromJson(json['subscription'] as Map<String, dynamic>),
     );
   }
 
   static List<ChannelWithSubscription> fromJsonArray(List<dynamic> jsonArr) {
-    return jsonArr.map<ChannelWithSubscription>((e) => ChannelWithSubscription.fromJson(e)).toList();
+    return jsonArr.map<ChannelWithSubscription>((e) => ChannelWithSubscription.fromJson(e as Map<String, dynamic>)).toList();
   }
 }
diff --git a/flutter/lib/models/message.dart b/flutter/lib/models/message.dart
index faa65fd..cee7fca 100644
--- a/flutter/lib/models/message.dart
+++ b/flutter/lib/models/message.dart
@@ -31,26 +31,26 @@ class Message {
 
   factory Message.fromJson(Map<String, dynamic> json) {
     return Message(
-      messageID: json['message_id'],
-      senderUserID: json['sender_user_id'],
-      channelInternalName: json['channel_internal_name'],
-      channelID: json['channel_id'],
-      senderName: json['sender_name'],
-      senderIP: json['sender_ip'],
-      timestamp: json['timestamp'],
-      title: json['title'],
-      content: json['content'],
-      priority: json['priority'],
-      userMessageID: json['usr_message_id'],
-      usedKeyID: json['used_key_id'],
-      trimmed: json['trimmed'],
+      messageID: json['message_id'] as String,
+      senderUserID: json['sender_user_id'] as String,
+      channelInternalName: json['channel_internal_name'] as String,
+      channelID: json['channel_id'] as String,
+      senderName: json['sender_name'] as String,
+      senderIP: json['sender_ip'] as String,
+      timestamp: json['timestamp'] as String,
+      title: json['title'] as String,
+      content: json['content'] as String,
+      priority: json['priority'] as int,
+      userMessageID: json['usr_message_id'] as String,
+      usedKeyID: json['used_key_id'] as String,
+      trimmed: json['trimmed'] as bool,
     );
   }
 
-  static fromPaginatedJsonArray(Map<String, dynamic> data, String keyMessages, String keyToken) {
+  static (String, List<Message>) fromPaginatedJsonArray(Map<String, dynamic> data, String keyMessages, String keyToken) {
     final npt = data[keyToken] as String;
 
-    final messages = (data[keyMessages] as List<dynamic>).map<Message>((e) => Message.fromJson(e)).toList();
+    final messages = (data[keyMessages] as List<dynamic>).map<Message>((e) => Message.fromJson(e as Map<String, dynamic>)).toList();
 
     return (npt, messages);
   }
diff --git a/flutter/lib/models/subscription.dart b/flutter/lib/models/subscription.dart
index b8432f4..f927565 100644
--- a/flutter/lib/models/subscription.dart
+++ b/flutter/lib/models/subscription.dart
@@ -19,13 +19,13 @@ class Subscription {
 
   factory Subscription.fromJson(Map<String, dynamic> json) {
     return Subscription(
-      subscriptionID: json['subscription_id'],
-      subscriberUserID: json['subscriber_user_id'],
-      channelOwnerUserID: json['channel_owner_user_id'],
-      channelID: json['channel_id'],
-      channelInternalName: json['channel_internal_name'],
-      timestampCreated: json['timestamp_created'],
-      confirmed: json['confirmed'],
+      subscriptionID: json['subscription_id'] as String,
+      subscriberUserID: json['subscriber_user_id'] as String,
+      channelOwnerUserID: json['channel_owner_user_id'] as String,
+      channelID: json['channel_id'] as String,
+      channelInternalName: json['channel_internal_name'] as String,
+      timestampCreated: json['timestamp_created'] as String,
+      confirmed: json['confirmed'] as bool,
     );
   }
 }
diff --git a/flutter/lib/models/user.dart b/flutter/lib/models/user.dart
index 28cc99a..c8f4eb8 100644
--- a/flutter/lib/models/user.dart
+++ b/flutter/lib/models/user.dart
@@ -41,24 +41,24 @@ class User {
 
   factory User.fromJson(Map<String, dynamic> json) {
     return User(
-      userID: json['user_id'],
-      username: json['username'],
-      timestampCreated: json['timestamp_created'],
-      timestampLastRead: json['timestamp_lastread'],
-      timestampLastSent: json['timestamp_lastsent'],
-      messagesSent: json['messages_sent'],
-      quotaUsed: json['quota_used'],
-      quotaRemaining: json['quota_remaining'],
-      quotaPerDay: json['quota_max'],
-      isPro: json['is_pro'],
-      defaultChannel: json['default_channel'],
-      maxBodySize: json['max_body_size'],
-      maxTitleLength: json['max_title_length'],
-      defaultPriority: json['default_priority'],
-      maxChannelNameLength: json['max_channel_name_length'],
-      maxChannelDescriptionLength: json['max_channel_description_length'],
-      maxSenderNameLength: json['max_sender_name_length'],
-      maxUserMessageIDLength: json['max_user_message_id_length'],
+      userID: json['user_id'] as String,
+      username: json['username'] as String?,
+      timestampCreated: json['timestamp_created'] as String,
+      timestampLastRead: json['timestamp_lastread'] as String?,
+      timestampLastSent: json['timestamp_lastsent'] as String?,
+      messagesSent: json['messages_sent'] as int,
+      quotaUsed: json['quota_used'] as int,
+      quotaRemaining: json['quota_remaining'] as int,
+      quotaPerDay: json['quota_max'] as int,
+      isPro: json['is_pro'] as bool,
+      defaultChannel: json['default_channel'] as String,
+      maxBodySize: json['max_body_size'] as int,
+      maxTitleLength: json['max_title_length'] as int,
+      defaultPriority: json['default_priority'] as int,
+      maxChannelNameLength: json['max_channel_name_length'] as int,
+      maxChannelDescriptionLength: json['max_channel_description_length'] as int,
+      maxSenderNameLength: json['max_sender_name_length'] as int,
+      maxUserMessageIDLength: json['max_user_message_id_length'] as int,
     );
   }
 }
diff --git a/flutter/lib/pages/debug/debug_requests.dart b/flutter/lib/pages/debug/debug_requests.dart
index 65f0754..27331e2 100644
--- a/flutter/lib/pages/debug/debug_requests.dart
+++ b/flutter/lib/pages/debug/debug_requests.dart
@@ -25,62 +25,9 @@ class _DebugRequestsPageState extends State<DebugRequestsPage> {
             itemBuilder: (context, listIndex) {
               final req = requestsBox.getAt(requestsBox.length - listIndex - 1)!;
               if (req.type == 'SUCCESS') {
-                return Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 0, vertical: 2.0),
-                  child: GestureDetector(
-                    onTap: () => Navigator.push(context, MaterialPageRoute(builder: (context) => DebugRequestViewPage(request: req))),
-                    child: ListTile(
-                      title: Row(
-                        children: [
-                          SizedBox(
-                            width: 120,
-                            child: Text(_dateFormat.format(req.timestampStart), style: TextStyle(fontSize: 12)),
-                          ),
-                          Expanded(
-                            child: Text(req.name, style: TextStyle(fontWeight: FontWeight.bold)),
-                          ),
-                          SizedBox(width: 2),
-                          Text('${req.timestampEnd.difference(req.timestampStart).inMilliseconds}ms', style: TextStyle(fontSize: 12)),
-                        ],
-                      ),
-                      subtitle: Text(req.type),
-                    ),
-                  ),
-                );
+                return buildItemSuccess(context, req);
               } else {
-                return Padding(
-                  padding: const EdgeInsets.symmetric(horizontal: 0, vertical: 2.0),
-                  child: GestureDetector(
-                    onTap: () => Navigator.push(context, MaterialPageRoute(builder: (context) => DebugRequestViewPage(request: req))),
-                    child: ListTile(
-                        tileColor: Theme.of(context).colorScheme.errorContainer,
-                        textColor: Theme.of(context).colorScheme.onErrorContainer,
-                        title: Row(
-                          children: [
-                            SizedBox(
-                              width: 120,
-                              child: Text(_dateFormat.format(req.timestampStart), style: TextStyle(fontSize: 12)),
-                            ),
-                            Expanded(
-                              child: Text(req.name, style: TextStyle(fontWeight: FontWeight.bold)),
-                            ),
-                            SizedBox(width: 2),
-                            Text('${req.timestampEnd.difference(req.timestampStart).inMilliseconds}ms', style: TextStyle(fontSize: 12)),
-                          ],
-                        ),
-                        subtitle: Column(
-                          crossAxisAlignment: CrossAxisAlignment.start,
-                          children: [
-                            Text(req.type),
-                            Text(
-                              req.error,
-                              maxLines: 1,
-                              overflow: TextOverflow.ellipsis,
-                            ),
-                          ],
-                        )),
-                  ),
-                );
+                return buildItemError(context, req);
               }
             },
           );
@@ -88,4 +35,65 @@ class _DebugRequestsPageState extends State<DebugRequestsPage> {
       ),
     );
   }
+
+  Padding buildItemError(BuildContext context, SCNRequest req) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 0, vertical: 2.0),
+      child: GestureDetector(
+        onTap: () => Navigator.push(context, MaterialPageRoute<DebugRequestViewPage>(builder: (context) => DebugRequestViewPage(request: req))),
+        child: ListTile(
+            tileColor: Theme.of(context).colorScheme.errorContainer,
+            textColor: Theme.of(context).colorScheme.onErrorContainer,
+            title: Row(
+              children: [
+                SizedBox(
+                  width: 120,
+                  child: Text(_dateFormat.format(req.timestampStart), style: TextStyle(fontSize: 12)),
+                ),
+                Expanded(
+                  child: Text(req.name, style: TextStyle(fontWeight: FontWeight.bold)),
+                ),
+                SizedBox(width: 2),
+                Text('${req.timestampEnd.difference(req.timestampStart).inMilliseconds}ms', style: TextStyle(fontSize: 12)),
+              ],
+            ),
+            subtitle: Column(
+              crossAxisAlignment: CrossAxisAlignment.start,
+              children: [
+                Text(req.type),
+                Text(
+                  req.error,
+                  maxLines: 1,
+                  overflow: TextOverflow.ellipsis,
+                ),
+              ],
+            )),
+      ),
+    );
+  }
+
+  Padding buildItemSuccess(BuildContext context, SCNRequest req) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 0, vertical: 2.0),
+      child: GestureDetector(
+        onTap: () => Navigator.push(context, MaterialPageRoute<DebugRequestViewPage>(builder: (context) => DebugRequestViewPage(request: req))),
+        child: ListTile(
+          title: Row(
+            children: [
+              SizedBox(
+                width: 120,
+                child: Text(_dateFormat.format(req.timestampStart), style: TextStyle(fontSize: 12)),
+              ),
+              Expanded(
+                child: Text(req.name, style: TextStyle(fontWeight: FontWeight.bold)),
+              ),
+              SizedBox(width: 2),
+              Text('${req.timestampEnd.difference(req.timestampStart).inMilliseconds}ms', style: TextStyle(fontSize: 12)),
+            ],
+          ),
+          subtitle: Text(req.type),
+        ),
+      ),
+    );
+  }
 }
diff --git a/flutter/lib/pages/message_list/message_list.dart b/flutter/lib/pages/message_list/message_list.dart
index 38b0702..818f022 100644
--- a/flutter/lib/pages/message_list/message_list.dart
+++ b/flutter/lib/pages/message_list/message_list.dart
@@ -48,7 +48,7 @@ class _MessageListPageState extends State<MessageListPage> {
     try {
       if (_channels == null) {
         final channels = await APIClient.getChannelList(acc.auth!, ChannelSelector.allAny);
-        _channels = Map.fromIterable(channels, key: (e) => e.channelID);
+        _channels = <String, ChannelWithSubscription>{for (var v in channels) v.channelID: v};
       }
 
       final (npt, newItems) = await APIClient.getMessageList(acc.auth!, thisPageToken, _pageSize);
@@ -76,7 +76,7 @@ class _MessageListPageState extends State<MessageListPage> {
             message: item,
             allChannels: _channels ?? {},
             onPressed: () {
-              Navigator.push(context, MaterialPageRoute(builder: (context) => MessageViewPage(message: item)));
+              Navigator.push(context, MaterialPageRoute<MessageViewPage>(builder: (context) => MessageViewPage(message: item)));
             },
           ),
         ),
diff --git a/flutter/lib/pages/message_list/message_list_item.dart b/flutter/lib/pages/message_list/message_list_item.dart
index b2742be..a76d3ac 100644
--- a/flutter/lib/pages/message_list/message_list_item.dart
+++ b/flutter/lib/pages/message_list/message_list_item.dart
@@ -145,7 +145,7 @@ class MessageListItem extends StatelessWidget {
     );
   }
 
-  processContent(String? v) {
+  String processContent(String? v) {
     if (v == null) {
       return '';
     }
@@ -158,7 +158,7 @@ class MessageListItem extends StatelessWidget {
     return lines.sublist(0, min(_lineCount, lines.length)).join("\n").trim();
   }
 
-  processTitle(String? v) {
+  String processTitle(String? v) {
     if (v == null) {
       return '';
     }
@@ -174,7 +174,7 @@ class MessageListItem extends StatelessWidget {
     return allChannels[message.channelID]?.displayName ?? message.channelInternalName;
   }
 
-  showChannel(Message message) {
+  bool showChannel(Message message) {
     return message.channelInternalName != 'main';
   }
 }
diff --git a/flutter/lib/pages/send/root.dart b/flutter/lib/pages/send/root.dart
index c4ba722..1f2002f 100644
--- a/flutter/lib/pages/send/root.dart
+++ b/flutter/lib/pages/send/root.dart
@@ -79,7 +79,7 @@ class _SendRootPageState extends State<SendRootPage> {
     //...
   }
 
-  _buildQRCode(BuildContext context, UserAccount acc) {
+  Widget _buildQRCode(BuildContext context, UserAccount acc) {
     if (acc.auth == null) {
       return const Placeholder();
     }
diff --git a/flutter/lib/state/globals.dart b/flutter/lib/state/globals.dart
index 70287aa..8a3ffb8 100644
--- a/flutter/lib/state/globals.dart
+++ b/flutter/lib/state/globals.dart
@@ -18,7 +18,7 @@ class Globals {
   String platform = '';
   String hostname = '';
 
-  init() async {
+  Future<void> init() async {
     PackageInfo packageInfo = await PackageInfo.fromPlatform();
 
     this.appName = packageInfo.appName;
diff --git a/flutter/lib/state/user_account.dart b/flutter/lib/state/user_account.dart
index d2fb8b8..bc5a3cc 100644
--- a/flutter/lib/state/user_account.dart
+++ b/flutter/lib/state/user_account.dart
@@ -38,7 +38,7 @@ class UserAccount extends ChangeNotifier {
     notifyListeners();
   }
 
-  load() async {
+  void load() async {
     final prefs = await SharedPreferences.getInstance();
 
     final uid = prefs.getString('auth.userid');
@@ -51,7 +51,7 @@ class UserAccount extends ChangeNotifier {
     }
   }
 
-  save() async {
+  Future<void> save() async {
     final prefs = await SharedPreferences.getInstance();
     if (_auth == null) {
       await prefs.remove('auth.userid');
@@ -62,9 +62,9 @@ class UserAccount extends ChangeNotifier {
     }
   }
 
-  loadUser(bool force) async {
+  Future<User> loadUser(bool force) async {
     if (!force && _user != null) {
-      return _user;
+      return _user!;
     }
 
     if (_auth == null) {