diff --git a/lib/config/macos_config.dart b/lib/config/macos_config.dart
index a7553f2544..cd65d04cbe 100644
--- a/lib/config/macos_config.dart
+++ b/lib/config/macos_config.dart
@@ -23,7 +23,7 @@ class MacOSConfig {
   });
 
   /// Creates [WebConfig] from [json]
-  factory MacOSConfig.fromJson(Map<dynamic, dynamic> json) {
+  factory MacOSConfig.fromJson(Map<String, dynamic> json) {
     return _$MacOSConfigFromJson(json);
   }
 
diff --git a/lib/config/web_config.dart b/lib/config/web_config.dart
index 4b3454d59d..6023f698b6 100644
--- a/lib/config/web_config.dart
+++ b/lib/config/web_config.dart
@@ -32,7 +32,7 @@ class WebConfig {
   });
 
   /// Creates [WebConfig] from [json]
-  factory WebConfig.fromJson(Map<dynamic, dynamic> json) {
+  factory WebConfig.fromJson(Map<String, dynamic> json) {
     return _$WebConfigFromJson(json);
   }
 
diff --git a/lib/config/windows_config.dart b/lib/config/windows_config.dart
index 32483cc243..f4cf7260aa 100644
--- a/lib/config/windows_config.dart
+++ b/lib/config/windows_config.dart
@@ -27,12 +27,12 @@ class WindowsConfig {
   });
 
   /// Creates [WindowsConfig] from [json]
-  factory WindowsConfig.fromJson(Map<dynamic, dynamic> json) {
+  factory WindowsConfig.fromJson(Map<String, dynamic> json) {
     return _$WindowsConfigFromJson(json);
   }
 
   /// Creates [Map] from [WindowsConfig]
-  Map<dynamic, dynamic> toJson() => _$WindowsConfigToJson(this);
+  Map<String, dynamic> toJson() => _$WindowsConfigToJson(this);
 
   @override
   String toString() => 'WindowsConfig: ${toJson()}';
diff --git a/test/windows/windows_icon_generator_test.mocks.dart b/test/windows/windows_icon_generator_test.mocks.dart
index 9cd13510eb..cb96f9d5c4 100644
--- a/test/windows/windows_icon_generator_test.mocks.dart
+++ b/test/windows/windows_icon_generator_test.mocks.dart
@@ -157,13 +157,13 @@ class MockWindowsConfig extends _i1.Mock implements _i5.WindowsConfig {
       ) as bool);
 
   @override
-  Map<dynamic, dynamic> toJson() => (super.noSuchMethod(
+  Map<String, dynamic> toJson() => (super.noSuchMethod(
         Invocation.method(
           #toJson,
           [],
         ),
         returnValue: <dynamic, dynamic>{},
-      ) as Map<dynamic, dynamic>);
+      ) as Map<String, dynamic>);
 }
 
 /// A class which mocks [FLILogger].