diff --git a/CHANGELOG.md b/CHANGELOG.md
index 63cc736..8df1b64 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## [0.0.1-dev.10]
+
+- chore: migrate to null-safety
+
 ## [0.0.1-dev.9]
 
 - fix: rpc to return PostgrestTransformBuilder
diff --git a/example/main.dart b/example/main.dart
index be59c81..f2461f7 100644
--- a/example/main.dart
+++ b/example/main.dart
@@ -1,6 +1,6 @@
 import 'package:supabase/supabase.dart';
 
-void main() async {
+Future<void> main() async {
   const supabaseUrl = '';
   const supabaseKey = '';
   final client = SupabaseClient(supabaseUrl, supabaseKey);
@@ -19,13 +19,13 @@ void main() async {
   final subscription1 =
       client.from('countries').on(SupabaseEventTypes.delete, (x) {
     print('on countries.delete: ${x.table} ${x.eventType} ${x.oldRecord}');
-  }).subscribe((String event, {String errorMsg}) {
+  }).subscribe((String event, {String? errorMsg}) {
     print('event: $event error: $errorMsg');
   });
 
   final subscription2 = client.from('todos').on(SupabaseEventTypes.insert, (x) {
     print('on todos.insert: ${x.table} ${x.eventType} ${x.newRecord}');
-  }).subscribe((String event, {String errorMsg}) {
+  }).subscribe((String event, {String? errorMsg}) {
     print('event: $event error: $errorMsg');
   });
 
diff --git a/lib/src/auth_user.dart b/lib/src/auth_user.dart
index 43c8c70..d5646d2 100644
--- a/lib/src/auth_user.dart
+++ b/lib/src/auth_user.dart
@@ -2,16 +2,16 @@ import 'package:gotrue/gotrue.dart' show User;
 
 class AuthUser extends User {
   AuthUser(
-      {String id,
-      Map<String, dynamic> appMetadata,
-      Map<String, dynamic> userMetadata,
-      String aud,
-      String email,
-      String createdAt,
-      String confirmedAt,
-      String lastSignInAt,
-      String role,
-      String updatedAt})
+      {required String id,
+      required Map<String, dynamic> appMetadata,
+      required Map<String, dynamic> userMetadata,
+      required String aud,
+      required String email,
+      required String createdAt,
+      String? confirmedAt,
+      String? lastSignInAt,
+      required String role,
+      required String updatedAt})
       : super(
             id: id,
             appMetadata: appMetadata,
diff --git a/lib/src/supabase.dart b/lib/src/supabase.dart
index eb3c100..81484b3 100644
--- a/lib/src/supabase.dart
+++ b/lib/src/supabase.dart
@@ -7,26 +7,22 @@ import 'package:realtime_client/realtime_client.dart';
 import 'supabase_query_builder.dart';
 
 class SupabaseClient {
-  String supabaseUrl;
-  String supabaseKey;
-  String schema;
-  String restUrl;
-  String realtimeUrl;
-  String authUrl;
+  final String supabaseUrl;
+  final String supabaseKey;
+  final String schema;
+  final String restUrl;
+  final String realtimeUrl;
+  final String authUrl;
 
-  GoTrueClient auth;
-  RealtimeClient realtime;
+  late final GoTrueClient auth;
+  late final RealtimeClient realtime;
 
   SupabaseClient(this.supabaseUrl, this.supabaseKey,
-      {String schema, bool autoRefreshToken = true}) {
-    if (supabaseUrl == null) throw 'supabaseUrl is required.';
-    if (supabaseKey == null) throw 'supabaseKey is required.';
-
-    restUrl = '$supabaseUrl/rest/v1';
-    realtimeUrl = '$supabaseUrl/realtime/v1'.replaceAll('http', 'ws');
-    authUrl = '$supabaseUrl/auth/v1';
-    schema = schema ?? 'public';
-
+      {String? schema, bool autoRefreshToken = true})
+      : restUrl = '$supabaseUrl/rest/v1',
+        realtimeUrl = '$supabaseUrl/realtime/v1'.replaceAll('http', 'ws'),
+        authUrl = '$supabaseUrl/auth/v1',
+        schema = schema ?? 'public' {
     auth = _initSupabaseAuthClient(autoRefreshToken: autoRefreshToken);
     realtime = _initRealtimeClient();
   }
@@ -44,7 +40,7 @@ class SupabaseClient {
   }
 
   /// Perform a stored procedure call.
-  PostgrestTransformBuilder rpc(String fn, {Map<String, String> params}) {
+  PostgrestTransformBuilder rpc(String fn, {Map<String, String>? params}) {
     final rest = _initPostgRESTClient();
     return rest.rpc(fn, params: params);
   }
@@ -54,8 +50,8 @@ class SupabaseClient {
     final completer = Completer<int>();
 
     await _closeSubscription(subscription);
-    final openSubscriptions = getSubscriptions()?.length;
-    if (openSubscriptions == null || openSubscriptions == 0) {
+    final openSubscriptions = getSubscriptions().length;
+    if (openSubscriptions == 0) {
       realtime.disconnect();
     }
     completer.complete(openSubscriptions);
@@ -68,7 +64,7 @@ class SupabaseClient {
     return realtime.channels;
   }
 
-  GoTrueClient _initSupabaseAuthClient({bool autoRefreshToken}) {
+  GoTrueClient _initSupabaseAuthClient({bool? autoRefreshToken}) {
     return GoTrueClient(
         url: authUrl,
         headers: {
diff --git a/lib/src/supabase_query_builder.dart b/lib/src/supabase_query_builder.dart
index 7491d40..459ad1e 100644
--- a/lib/src/supabase_query_builder.dart
+++ b/lib/src/supabase_query_builder.dart
@@ -8,11 +8,11 @@ import 'supabase_realtime_payload.dart';
 typedef Callback = void Function(SupabaseRealtimePayload payload);
 
 class SupabaseQueryBuilder extends PostgrestQueryBuilder {
-  SupabaseRealtimeClient _subscription;
-  RealtimeClient _realtime;
+  late final SupabaseRealtimeClient _subscription;
+  late final RealtimeClient _realtime;
 
   SupabaseQueryBuilder(String url, RealtimeClient realtime,
-      {Map<String, String> headers = const {}, String schema, String table})
+      {Map<String, String> headers = const {}, String? schema, String? table})
       : super(url, headers: headers, schema: schema) {
     _subscription =
         SupabaseRealtimeClient(realtime, schema ?? 'public', table ?? '*');
diff --git a/lib/src/supabase_realtime_client.dart b/lib/src/supabase_realtime_client.dart
index 4be3fcd..303221a 100644
--- a/lib/src/supabase_realtime_client.dart
+++ b/lib/src/supabase_realtime_client.dart
@@ -5,10 +5,10 @@ import 'supabase_realtime_payload.dart';
 
 typedef Callback = void Function(SupabaseRealtimePayload payload);
 
-typedef SubscribeCallback = void Function(String event, {String errorMsg});
+typedef SubscribeCallback = void Function(String event, {String? errorMsg});
 
 class SupabaseRealtimeClient {
-  RealtimeSubscription subscription;
+  late final RealtimeSubscription subscription;
 
   SupabaseRealtimeClient(
       RealtimeClient socket, String schema, String tableName) {
@@ -31,15 +31,18 @@ class SupabaseRealtimeClient {
   }
 
   /// Enables the subscription.
-  RealtimeSubscription subscribe([SubscribeCallback callback]) {
-    subscription.onError((e) => callback('SUBSCRIPTION_ERROR', errorMsg: e));
-    subscription.onClose(() => callback('CLOSED'));
+  RealtimeSubscription subscribe([SubscribeCallback? callback]) {
+    subscription
+        .onError((e) => callback?.call('SUBSCRIPTION_ERROR', errorMsg: e));
+    subscription.onClose(() => callback?.call('CLOSED'));
     subscription
         .subscribe()
-        .receive('ok', (_) => callback('SUBSCRIBED'))
-        .receive('error',
-            (res) => callback('SUBSCRIPTION_ERROR', errorMsg: res.toString()))
-        .receive('timeout', (_) => callback('RETRYING_AFTER_TIMEOUT'));
+        .receive('ok', (_) => callback?.call('SUBSCRIBED'))
+        .receive(
+            'error',
+            (res) =>
+                callback?.call('SUBSCRIPTION_ERROR', errorMsg: res.toString()))
+        .receive('timeout', (_) => callback?.call('RETRYING_AFTER_TIMEOUT'));
     return subscription;
   }
 }
diff --git a/lib/src/supabase_realtime_payload.dart b/lib/src/supabase_realtime_payload.dart
index c589c45..450955c 100644
--- a/lib/src/supabase_realtime_payload.dart
+++ b/lib/src/supabase_realtime_payload.dart
@@ -1,49 +1,56 @@
 import 'package:realtime_client/realtime_client.dart';
 
 class SupabaseRealtimePayload {
-  String commitTimestamp;
+  final String commitTimestamp;
 
   /// 'INSERT' | 'UPDATE' | 'DELETE'
-  String eventType;
-  String schema;
-  String table;
+  final String eventType;
+  final String schema;
+  final String table;
 
   /// The new record. Present for 'INSERT' and 'UPDATE' events
-  dynamic newRecord;
+  final dynamic newRecord;
 
   /// The previous record. Present for 'UPDATE' and 'DELETE' events
-  dynamic oldRecord;
+  final dynamic oldRecord;
 
-  SupabaseRealtimePayload(
-      {this.commitTimestamp,
-      this.eventType,
-      this.schema,
-      this.table,
-      this.newRecord,
-      this.oldRecord});
+  SupabaseRealtimePayload({
+    required this.commitTimestamp,
+    required this.eventType,
+    required this.schema,
+    required this.table,
+    required this.newRecord,
+    required this.oldRecord,
+  });
 
   factory SupabaseRealtimePayload.fromJson(Map<String, dynamic> json) {
-    final obj = SupabaseRealtimePayload();
-    obj.schema = json['schema'] as String;
-    obj.table = json['table'] as String;
-    obj.commitTimestamp = json['commit_timestamp'] as String;
-    obj.eventType = json['type'] as String;
-
+    final schema = json['schema'] as String;
+    final table = json['table'] as String;
+    final commitTimestamp = json['commit_timestamp'] as String;
+    final eventType = json['type'] as String;
+    Map<dynamic, dynamic>? newRecord;
     if (json['type'] == 'INSERT' || json['type'] == 'UPDATE') {
-      final columns = obj.convertColumnList(json['columns'] as List<dynamic>);
-      final records = json['record'] as Map<String, dynamic> ?? {};
-      obj.newRecord = convertChangeData(columns, records);
+      final columns = convertColumnList(json['columns'] as List<dynamic>?);
+      final records = json['record'] as Map<String, dynamic>? ?? {};
+      newRecord = convertChangeData(columns, records);
     }
-
+    Map<dynamic, dynamic>? oldRecord;
     if (json['type'] == 'UPDATE' || json['type'] == 'DELETE') {
-      final columns = obj.convertColumnList(json['columns'] as List<dynamic>);
-      final records = json['old_record'] as Map<String, dynamic> ?? {};
-      obj.oldRecord = convertChangeData(columns, records);
+      final columns = convertColumnList(json['columns'] as List<dynamic>?);
+      final records = json['old_record'] as Map<String, dynamic>? ?? {};
+      oldRecord = convertChangeData(columns, records);
     }
-    return obj;
+    return SupabaseRealtimePayload(
+      table: table,
+      schema: schema,
+      commitTimestamp: commitTimestamp,
+      eventType: eventType,
+      newRecord: newRecord,
+      oldRecord: oldRecord,
+    );
   }
 
-  List<Map<String, dynamic>> convertColumnList(List<dynamic> columns) {
+  static List<Map<String, dynamic>> convertColumnList(List<dynamic>? columns) {
     final result = <Map<String, dynamic>>[];
     if (columns != null) {
       for (final column in columns) {
diff --git a/pubspec.yaml b/pubspec.yaml
index 7f52506..bc3c7fc 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,17 +1,17 @@
 name: supabase
 description: A dart client for Supabase. This client makes it simple for developers to build secure and scalable products.
-version: 0.0.1-dev.9
+version: 0.0.1-dev.10
 homepage: "https://supabase.io"
 repository: "https://github.com/supabase/supabase-dart"
 
 environment:
-  sdk: ">=2.8.1 <3.0.0"
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
-  gotrue: ^0.0.1-dev.7
-  postgrest: ^0.0.7
-  realtime_client: ^0.0.7
+  gotrue: ^0.0.1-dev.9
+  postgrest: ^0.0.8
+  realtime_client: ^0.0.8
 
 dev_dependencies:
-  test: ^1.15.4
-  lint: ^1.3.0
+  lint: ^1.5.2
+  test: ^1.16.5
diff --git a/test/client_test.dart b/test/client_test.dart
index a4c1039..3e0a728 100644
--- a/test/client_test.dart
+++ b/test/client_test.dart
@@ -4,7 +4,7 @@ import 'package:test/test.dart';
 void main() {
   const supabaseUrl = '';
   const supabaseKey = '';
-  SupabaseClient client;
+  late SupabaseClient client;
 
   setUp(() {
     client = SupabaseClient(supabaseUrl, supabaseKey);