diff --git a/example/main.dart b/example/main.dart
index ebff8ce8d1..68f5ee964c 100644
--- a/example/main.dart
+++ b/example/main.dart
@@ -15,15 +15,15 @@ Future<Null> main(List<String> rawArgs) async {
     exit(1);
   }
 
-  final String dsn = rawArgs.single;
-  final SentryClient client = SentryClient(dsn: dsn);
+  final dsn = rawArgs.single;
+  final client = SentryClient(dsn: dsn);
 
   try {
     await foo();
   } catch (error, stackTrace) {
     print('Reporting the following stack trace: ');
     print(stackTrace);
-    final SentryResponse response = await client.captureException(
+    final response = await client.captureException(
       exception: error,
       stackTrace: stackTrace,
     );
diff --git a/lib/src/base.dart b/lib/src/base.dart
index 3af2883a24..2bc611c4c4 100644
--- a/lib/src/base.dart
+++ b/lib/src/base.dart
@@ -121,12 +121,12 @@ abstract class SentryClient {
 
   @visibleForTesting
   String get postUri {
-    String port = dsnUri.hasPort &&
+    var port = dsnUri.hasPort &&
             ((dsnUri.scheme == 'http' && dsnUri.port != 80) ||
                 (dsnUri.scheme == 'https' && dsnUri.port != 443))
         ? ':${dsnUri.port}'
         : '';
-    int pathLength = dsnUri.pathSegments.length;
+    var pathLength = dsnUri.pathSegments.length;
     String apiPath;
     if (pathLength > 1) {
       // some paths would present before the projectID in the dsnUri
@@ -143,16 +143,16 @@ abstract class SentryClient {
     @required Event event,
     StackFrameFilter stackFrameFilter,
   }) async {
-    final DateTime now = _clock();
-    String authHeader = 'Sentry sentry_version=6, sentry_client=$sentryClient, '
+    final now = _clock();
+    var authHeader = 'Sentry sentry_version=6, sentry_client=$sentryClient, '
         'sentry_timestamp=${now.millisecondsSinceEpoch}, sentry_key=$publicKey';
     if (secretKey != null) {
       authHeader += ', sentry_secret=$secretKey';
     }
 
-    final Map<String, String> headers = buildHeaders(authHeader);
+    final headers = buildHeaders(authHeader);
 
-    final Map<String, dynamic> data = <String, dynamic>{
+    final data = <String, dynamic>{
       'project': projectId,
       'event_id': _uuidGenerator(),
       'timestamp': formatDateAsIso8601WithSecondPrecision(now),
@@ -179,15 +179,14 @@ abstract class SentryClient {
 
     final body = bodyEncoder(data, headers);
 
-    final Response response = await httpClient.post(
+    final response = await httpClient.post(
       postUri,
       headers: headers,
       body: body,
     );
 
     if (response.statusCode != 200) {
-      String errorMessage =
-          'Sentry.io responded with HTTP ${response.statusCode}';
+      var errorMessage = 'Sentry.io responded with HTTP ${response.statusCode}';
       if (response.headers['x-sentry-error'] != null) {
         errorMessage += ': ${response.headers['x-sentry-error']}';
       }
@@ -203,7 +202,7 @@ abstract class SentryClient {
     @required dynamic exception,
     dynamic stackTrace,
   }) {
-    final Event event = Event(
+    final event = Event(
       exception: exception,
       stackTrace: stackTrace,
     );
@@ -430,7 +429,7 @@ class Event {
   /// Serializes this event to JSON.
   Map<String, dynamic> toJson(
       {StackFrameFilter stackFrameFilter, String origin}) {
-    final Map<String, dynamic> json = <String, dynamic>{
+    final json = <String, dynamic>{
       'platform': sdkPlatform,
       'sdk': {
         'version': sdkVersion,
@@ -568,6 +567,7 @@ class Contexts {
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     Map<String, dynamic> deviceMap;
@@ -593,25 +593,25 @@ class Contexts {
 
     if (runtimes != null) {
       if (runtimes.length == 1) {
-        final Runtime runtime = runtimes[0];
+        final runtime = runtimes[0];
         if (runtime != null) {
-          final String key = runtime.key ?? 'runtime';
+          final key = runtime.key ?? 'runtime';
           json[key] = runtime.toJson();
         }
       } else if (runtimes.length > 1) {
         for (final runtime in runtimes) {
           if (runtime != null) {
-            String key = runtime.key ?? runtime.name.toLowerCase();
+            var key = runtime.key ?? runtime.name.toLowerCase();
 
             if (json.containsKey(key)) {
-              int k = 0;
+              var k = 0;
               while (json.containsKey(key)) {
                 key = '$key$k';
                 k++;
               }
             }
 
-            json[key] = runtime.toJson()..addAll({"type": "runtime"});
+            json[key] = runtime.toJson()..addAll({'type': 'runtime'});
           }
         }
       }
@@ -736,16 +736,17 @@ class Device {
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     String orientation;
 
     switch (this.orientation) {
       case Orientation.portrait:
-        orientation = "portait";
+        orientation = 'portait';
         break;
       case Orientation.landscape:
-        orientation = "landscape";
+        orientation = 'landscape';
         break;
     }
 
@@ -848,6 +849,7 @@ class OperatingSystem {
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     if (name != null) json['name'] = name;
@@ -891,10 +893,12 @@ class Runtime {
   final String rawDescription;
 
   const Runtime({this.key, this.name, this.version, this.rawDescription})
+      // ignore: prefer_is_empty
       : assert(key == null || key.length >= 1);
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     if (name != null) json['name'] = name;
@@ -945,6 +949,7 @@ class App {
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     if (name != null) json['app_name'] = name;
@@ -980,6 +985,7 @@ class Browser {
 
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
+    // ignore: omit_local_variable_types
     final Map<String, dynamic> json = {};
 
     if (name != null) json['name'] = name;
@@ -1039,11 +1045,11 @@ class User {
   /// Produces a [Map] that can be serialized to JSON.
   Map<String, dynamic> toJson() {
     return {
-      "id": id,
-      "username": username,
-      "email": email,
-      "ip_address": ipAddress,
-      "extras": extras,
+      'id': id,
+      'username': username,
+      'email': email,
+      'ip_address': ipAddress,
+      'extras': extras,
     };
   }
 }
@@ -1169,8 +1175,8 @@ class Dsn {
   });
 
   static Dsn parse(String dsn) {
-    final Uri uri = Uri.parse(dsn);
-    final List<String> userInfo = uri.userInfo.split(':');
+    final uri = Uri.parse(dsn);
+    final userInfo = uri.userInfo.split(':');
 
     assert(() {
       if (uri.pathSegments.isEmpty) {
diff --git a/lib/src/io.dart b/lib/src/io.dart
index b9a4ffaf27..f49734db20 100644
--- a/lib/src/io.dart
+++ b/lib/src/io.dart
@@ -102,7 +102,7 @@ class SentryIOClient extends SentryClient {
   ) {
     // [SentryIOClient] implement gzip compression
     // gzip compression is not available on browser
-    List<int> body = utf8.encode(json.encode(data));
+    var body = utf8.encode(json.encode(data));
     if (compressPayload) {
       headers['Content-Encoding'] = 'gzip';
       body = gzip.encode(body);
diff --git a/lib/src/stack_trace.dart b/lib/src/stack_trace.dart
index effbbb7857..ac488852c6 100644
--- a/lib/src/stack_trace.dart
+++ b/lib/src/stack_trace.dart
@@ -31,12 +31,12 @@ List<Map<String, dynamic>> encodeStackTrace(
   assert(stackTrace is String || stackTrace is StackTrace);
   origin ??= '';
 
-  final Chain chain = stackTrace is StackTrace
+  final chain = stackTrace is StackTrace
       ? Chain.forTrace(stackTrace)
       : Chain.parse(stackTrace);
 
-  final List<Map<String, dynamic>> frames = <Map<String, dynamic>>[];
-  for (int t = 0; t < chain.traces.length; t += 1) {
+  final frames = <Map<String, dynamic>>[];
+  for (var t = 0; t < chain.traces.length; t += 1) {
     final encodedFrames = chain.traces[t].frames
         .map((f) => encodeStackTraceFrame(f, origin: origin));
 
@@ -52,7 +52,7 @@ List<Map<String, dynamic>> encodeStackTrace(
 Map<String, dynamic> encodeStackTraceFrame(Frame frame, {String origin}) {
   origin ??= '';
 
-  final Map<String, dynamic> json = <String, dynamic>{
+  final json = <String, dynamic>{
     'abs_path': '$origin${_absolutePathForCrashReport(frame)}',
     'function': frame.member,
     'lineno': frame.line,
diff --git a/lib/src/utils.dart b/lib/src/utils.dart
index 25f824c2f4..197c55b7a9 100644
--- a/lib/src/utils.dart
+++ b/lib/src/utils.dart
@@ -27,7 +27,7 @@ void mergeAttributes(Map<String, dynamic> attributes,
 }
 
 String formatDateAsIso8601WithSecondPrecision(DateTime date) {
-  String iso = date.toIso8601String();
+  var iso = date.toIso8601String();
   final millisecondSeparatorIndex = iso.lastIndexOf('.');
   if (millisecondSeparatorIndex != -1) {
     iso = iso.substring(0, millisecondSeparatorIndex);
diff --git a/test/event_test.dart b/test/event_test.dart
index 47177641ac..15f51cabea 100644
--- a/test/event_test.dart
+++ b/test/event_test.dart
@@ -10,10 +10,10 @@ void main() {
     test('$Breadcrumb serializes', () {
       expect(
         Breadcrumb(
-          "example log",
+          'example log',
           DateTime.utc(2019),
           level: SeverityLevel.debug,
-          category: "test",
+          category: 'test',
         ).toJson(),
         <String, dynamic>{
           'timestamp': '2019-01-01T00:00:00',
@@ -25,15 +25,15 @@ void main() {
     });
     test('serializes to JSON', () {
       final user = User(
-          id: "user_id",
-          username: "username",
-          email: "email@email.com",
-          ipAddress: "127.0.0.1",
-          extras: {"foo": "bar"});
+          id: 'user_id',
+          username: 'username',
+          email: 'email@email.com',
+          ipAddress: '127.0.0.1',
+          extras: {'foo': 'bar'});
 
       final breadcrumbs = [
-        Breadcrumb("test log", DateTime.utc(2019),
-            level: SeverityLevel.debug, category: "test"),
+        Breadcrumb('test log', DateTime.utc(2019),
+            level: SeverityLevel.debug, category: 'test'),
       ];
 
       expect(
diff --git a/test/sentry_browser_test.dart b/test/sentry_browser_test.dart
index c7713139c0..2299d06a25 100644
--- a/test/sentry_browser_test.dart
+++ b/test/sentry_browser_test.dart
@@ -1,7 +1,7 @@
 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-@TestOn("browser")
+@TestOn('browser')
 
 import 'package:sentry/browser_client.dart';
 import 'package:sentry/sentry.dart';
diff --git a/test/sentry_io_test.dart b/test/sentry_io_test.dart
index db1e7255b0..07de56a1f7 100644
--- a/test/sentry_io_test.dart
+++ b/test/sentry_io_test.dart
@@ -1,7 +1,7 @@
 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
-@TestOn("vm")
+@TestOn('vm')
 
 import 'dart:io';
 
diff --git a/test/stack_trace_test.dart b/test/stack_trace_test.dart
index 3a7c3c355d..ad19aa8a3b 100644
--- a/test/stack_trace_test.dart
+++ b/test/stack_trace_test.dart
@@ -9,7 +9,7 @@ import 'package:test/test.dart';
 void main() {
   group('encodeStackTraceFrame', () {
     test('marks dart: frames as not app frames', () {
-      final Frame frame = Frame(Uri.parse('dart:core'), 1, 2, 'buzz');
+      final frame = Frame(Uri.parse('dart:core'), 1, 2, 'buzz');
       expect(encodeStackTraceFrame(frame), {
         'abs_path': 'dart:core',
         'function': 'buzz',
@@ -21,8 +21,7 @@ void main() {
     });
 
     test('cleanses absolute paths', () {
-      final Frame frame =
-          Frame(Uri.parse('file://foo/bar/baz.dart'), 1, 2, 'buzz');
+      final frame = Frame(Uri.parse('file://foo/bar/baz.dart'), 1, 2, 'buzz');
       expect(encodeStackTraceFrame(frame)['abs_path'], 'baz.dart');
     });
   });
@@ -81,6 +80,7 @@ void main() {
     });
 
     test('allows changing the stack frame list before sending', () {
+      // ignore: omit_local_variable_types
       StackFrameFilter filter =
           (list) => list.where((f) => f['abs_path'] != 'secret.dart').toList();
 
diff --git a/test/test_utils.dart b/test/test_utils.dart
index 3d47bba7df..29dc7e3edd 100644
--- a/test/test_utils.dart
+++ b/test/test_utils.dart
@@ -23,7 +23,7 @@ void testHeaders(
   bool compressPayload = true,
   bool withSecret = true,
 }) {
-  final Map<String, String> expectedHeaders = <String, String>{
+  final expectedHeaders = <String, String>{
     'Content-Type': 'application/json',
     'X-Sentry-Auth': 'Sentry sentry_version=6, '
         'sentry_client=${SentryClient.sentryClient}, '
@@ -43,17 +43,17 @@ void testHeaders(
   expect(headers, expectedHeaders);
 }
 
-testCaptureException(
+void testCaptureException(
   bool compressPayload,
   Codec<List<int>, List<int>> gzip,
   bool isWeb,
 ) async {
-  final ClockProvider fakeClockProvider = () => DateTime.utc(2017, 1, 2);
+  final fakeClockProvider = () => DateTime.utc(2017, 1, 2);
 
   String postUri;
   Map<String, String> headers;
   List<int> body;
-  final MockClient httpMock = MockClient((Request request) async {
+  final httpMock = MockClient((Request request) async {
     if (request.method == 'POST') {
       postUri = request.url.toString();
       headers = request.headers;
@@ -63,7 +63,7 @@ testCaptureException(
     fail('Unexpected request on ${request.method} ${request.url} in HttpMock');
   });
 
-  final SentryClient client = SentryClient(
+  final client = SentryClient(
     dsn: testDsn,
     httpClient: httpMock,
     clock: fakeClockProvider,
@@ -79,7 +79,7 @@ testCaptureException(
   try {
     throw ArgumentError('Test error');
   } catch (error, stackTrace) {
-    final SentryResponse response =
+    final response =
         await client.captureException(exception: error, stackTrace: stackTrace);
     expect(response.isSuccessful, true);
     expect(response.eventId, 'test-event-id');
@@ -172,7 +172,7 @@ testCaptureException(
 
 void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
   test('can parse DSN', () async {
-    final SentryClient client = SentryClient(dsn: testDsn);
+    final client = SentryClient(dsn: testDsn);
     expect(client.dsnUri, Uri.parse(testDsn));
     expect(client.postUri, 'https://sentry.example.com/api/1/store/');
     expect(client.publicKey, 'public');
@@ -182,7 +182,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
   });
 
   test('can parse DSN without secret', () async {
-    final SentryClient client = SentryClient(dsn: _testDsnWithoutSecret);
+    final client = SentryClient(dsn: _testDsnWithoutSecret);
     expect(client.dsnUri, Uri.parse(_testDsnWithoutSecret));
     expect(client.postUri, 'https://sentry.example.com/api/1/store/');
     expect(client.publicKey, 'public');
@@ -192,7 +192,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
   });
 
   test('can parse DSN with path', () async {
-    final SentryClient client = SentryClient(dsn: _testDsnWithPath);
+    final client = SentryClient(dsn: _testDsnWithPath);
     expect(client.dsnUri, Uri.parse(_testDsnWithPath));
     expect(client.postUri, 'https://sentry.example.com/path/api/1/store/');
     expect(client.publicKey, 'public');
@@ -201,7 +201,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
     await client.close();
   });
   test('can parse DSN with port', () async {
-    final SentryClient client = SentryClient(dsn: _testDsnWithPort);
+    final client = SentryClient(dsn: _testDsnWithPort);
     expect(client.dsnUri, Uri.parse(_testDsnWithPort));
     expect(client.postUri, 'https://sentry.example.com:8888/api/1/store/');
     expect(client.publicKey, 'public');
@@ -210,11 +210,11 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
     await client.close();
   });
   test('sends client auth header without secret', () async {
-    final ClockProvider fakeClockProvider = () => DateTime.utc(2017, 1, 2);
+    final fakeClockProvider = () => DateTime.utc(2017, 1, 2);
 
     Map<String, String> headers;
 
-    final MockClient httpMock = MockClient((Request request) async {
+    final httpMock = MockClient((Request request) async {
       if (request.method == 'POST') {
         headers = request.headers;
         return Response('{"id": "test-event-id"}', 200);
@@ -223,7 +223,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
           'Unexpected request on ${request.method} ${request.url} in HttpMock');
     });
 
-    final SentryClient client = SentryClient(
+    final client = SentryClient(
       dsn: _testDsnWithoutSecret,
       httpClient: httpMock,
       clock: fakeClockProvider,
@@ -239,7 +239,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
     try {
       throw ArgumentError('Test error');
     } catch (error, stackTrace) {
-      final SentryResponse response = await client.captureException(
+      final response = await client.captureException(
           exception: error, stackTrace: stackTrace);
       expect(response.isSuccessful, true);
       expect(response.eventId, 'test-event-id');
@@ -268,9 +268,9 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
   });
 
   test('reads error message from the x-sentry-error header', () async {
-    final ClockProvider fakeClockProvider = () => DateTime.utc(2017, 1, 2);
+    final fakeClockProvider = () => DateTime.utc(2017, 1, 2);
 
-    final MockClient httpMock = MockClient((Request request) async {
+    final httpMock = MockClient((Request request) async {
       if (request.method == 'POST') {
         return Response('', 401, headers: <String, String>{
           'x-sentry-error': 'Invalid api key',
@@ -280,7 +280,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
           'Unexpected request on ${request.method} ${request.url} in HttpMock');
     });
 
-    final SentryClient client = SentryClient(
+    final client = SentryClient(
       dsn: testDsn,
       httpClient: httpMock,
       clock: fakeClockProvider,
@@ -296,7 +296,7 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
     try {
       throw ArgumentError('Test error');
     } catch (error, stackTrace) {
-      final SentryResponse response = await client.captureException(
+      final response = await client.captureException(
           exception: error, stackTrace: stackTrace);
       expect(response.isSuccessful, false);
       expect(response.eventId, null);
@@ -308,10 +308,10 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
   });
 
   test('$Event userContext overrides client', () async {
-    final ClockProvider fakeClockProvider = () => DateTime.utc(2017, 1, 2);
+    final fakeClockProvider = () => DateTime.utc(2017, 1, 2);
 
     String loggedUserId; // used to find out what user context was sent
-    final MockClient httpMock = MockClient((Request request) async {
+    final httpMock = MockClient((Request request) async {
       if (request.method == 'POST') {
         var bodyData = request.bodyBytes;
         var decoded = Utf8Codec().decode(bodyData);
@@ -326,18 +326,18 @@ void runTest({Codec<List<int>, List<int>> gzip, bool isWeb = false}) {
     });
 
     final clientUserContext = User(
-        id: "client_user",
-        username: "username",
-        email: "email@email.com",
-        ipAddress: "127.0.0.1");
+        id: 'client_user',
+        username: 'username',
+        email: 'email@email.com',
+        ipAddress: '127.0.0.1');
     final eventUserContext = User(
-        id: "event_user",
-        username: "username",
-        email: "email@email.com",
-        ipAddress: "127.0.0.1",
-        extras: {"foo": "bar"});
+        id: 'event_user',
+        username: 'username',
+        email: 'email@email.com',
+        ipAddress: '127.0.0.1',
+        extras: {'foo': 'bar'});
 
-    final SentryClient client = SentryClient(
+    final client = SentryClient(
       dsn: testDsn,
       httpClient: httpMock,
       clock: fakeClockProvider,
diff --git a/test/utils_test.dart b/test/utils_test.dart
index 54d52155a2..8354eb5235 100644
--- a/test/utils_test.dart
+++ b/test/utils_test.dart
@@ -9,7 +9,7 @@ import 'package:sentry/src/utils.dart';
 void main() {
   group('mergeAttributes', () {
     test('merges attributes', () {
-      final Map<String, dynamic> target = <String, dynamic>{
+      final target = <String, dynamic>{
         'overwritten': 1,
         'unchanged': 2,
         'recursed': <String, dynamic>{
@@ -18,7 +18,7 @@ void main() {
         },
       };
 
-      final Map<String, dynamic> attributes = <String, dynamic>{
+      final attributes = <String, dynamic>{
         'overwritten': 2,
         'recursed': <String, dynamic>{
           'overwritten_child': [4, 5, 6],
@@ -58,7 +58,7 @@ void main() {
 
   group('formatDateAsIso8601WithSecondPrecision', () {
     test('strips sub-millisecond parts', () {
-      final DateTime testDate =
+      final testDate =
           DateTime.fromMillisecondsSinceEpoch(1502467721598, isUtc: true);
       expect(testDate.toIso8601String(), '2017-08-11T16:08:41.598Z');
       expect(formatDateAsIso8601WithSecondPrecision(testDate),