diff --git a/CHANGELOG.md b/CHANGELOG.md
index 79b1c30..44adbb3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,14 @@
+## 1.0.3
+
+- `YAMLWriter`:
+  - Added `allowUnquotedStrings`.
+  - Rename `identSize` to `indentSize`.
+  - Deprecate `identSize` field.
+- lints: ^2.0.1
+- test: ^1.22.0
+- dependency_validator: ^3.2.2
+- coverage: ^1.6.1
+
 ## 1.0.2
 
 - Fixed serialization of an empty `List` to `[]`
diff --git a/lib/src/yaml_writer_base.dart b/lib/src/yaml_writer_base.dart
index 05c9bf8..c4cf2f3 100644
--- a/lib/src/yaml_writer_base.dart
+++ b/lib/src/yaml_writer_base.dart
@@ -2,11 +2,28 @@ import 'dart:convert';
 
 /// YAML Writer.
 class YAMLWriter extends Converter<Object?, String> {
-  final int identSize;
+  /// The indentation size.
+  final int indentSize;
+
+  @Deprecated("Use `indentSize`.")
+  int get identSize => indentSize;
+
+  /// If `true` it will allow unquoted strings.
+  final bool allowUnquotedStrings;
 
   final String _ident;
 
-  YAMLWriter({this.identSize = 2}) : _ident = ''.padLeft(identSize, ' ');
+  YAMLWriter(
+      {int indentSize = 2,
+      @Deprecated("Use `indentSize`.") int? identSize,
+      this.allowUnquotedStrings = false})
+      : indentSize = _resolveIndentSize(indentSize, identSize),
+        _ident = ''.padLeft(_resolveIndentSize(indentSize, identSize), ' ');
+
+  static int _resolveIndentSize(int indentSize, int? identSize) {
+    var indent = (identSize ?? indentSize);
+    return indent < 0 ? 0 : indent;
+  }
 
   /// Used to convert objects to an encodable version.
   Object? Function(dynamic object)? toEncodable;
@@ -84,7 +101,14 @@ class YAMLWriter extends Converter<Object?, String> {
 
       return true;
     } else {
-      if (!node.contains("'")) {
+      var containsSingleQuote = node.contains("'");
+
+      if (allowUnquotedStrings &&
+          !containsSingleQuote &&
+          _isValidUnquotedString(node)) {
+        s.write(node);
+        return false;
+      } else if (!containsSingleQuote) {
         s.write("'");
         s.write(node);
         s.write("'");
@@ -99,6 +123,14 @@ class YAMLWriter extends Converter<Object?, String> {
     }
   }
 
+  static final _regexpInvalidUnquotedChars = RegExp(
+      r'[^0-9a-zA-ZàèìòùÀÈÌÒÙáéíóúýÁÉÍÓÚÝâêîôûÂÊÎÔÛãñõÃÑÕäëïöüÿÄËÏÖÜŸçÇßØøÅåÆæœ@/. \t-]');
+
+  bool _isValidUnquotedString(String s) =>
+      !_regexpInvalidUnquotedChars.hasMatch(s) &&
+      !s.startsWith('@') &&
+      !s.startsWith('-');
+
   static dynamic _defaultToEncodable(dynamic object) => object.toJson();
 
   bool _writeObject(Object node, StringBuffer s, {String currentIdent = ''}) {
diff --git a/pubspec.yaml b/pubspec.yaml
index 048cd1a..f817621 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,13 +1,13 @@
 name: yaml_writer
 description: A library to write YAML documents, supporting Object encoding and 'dart:convert' 'Converter'.
-version: 1.0.2
+version: 1.0.3
 homepage: https://github.com/gmpassos/yaml_writer
 
 environment:
   sdk: '>=2.12.0 <3.0.0'
 
 dev_dependencies:
-  lints: ^2.0.0
-  test: ^1.17.12
-  dependency_validator: ^3.2.0
-  coverage: ^1.1.0
+  lints: ^2.0.1
+  test: ^1.22.0
+  dependency_validator: ^3.2.2
+  coverage: ^1.6.1
diff --git a/test/yaml_writer_test.dart b/test/yaml_writer_test.dart
index 530e331..75e5c6d 100644
--- a/test/yaml_writer_test.dart
+++ b/test/yaml_writer_test.dart
@@ -7,6 +7,111 @@ void main() {
       print('---------------------------------------------');
     });
 
+    test('unquoted string', () {
+      var yamlWriter = YAMLWriter(allowUnquotedStrings: true);
+
+      var tree = {
+        'foo': {
+          's1': 'Unquoted string with some@email and a /path/file.',
+          's2': 'Quoted \$string.',
+          's3': '@Quoted string.',
+          's4': '-Quoted string.',
+          's5': 'UnQuoted@string.',
+          's6': 'UnQuoted-string.',
+        }
+      };
+
+      var yaml = yamlWriter.write(tree);
+
+      print(yaml);
+
+      expect(yaml, equals(r'''
+foo: 
+  s1: Unquoted string with some@email and a /path/file.
+  s2: 'Quoted $string.'
+  s3: '@Quoted string.'
+  s4: '-Quoted string.'
+  s5: UnQuoted@string.
+  s6: UnQuoted-string.
+'''));
+
+      expect(yamlWriter.convert(tree), equals(yaml));
+
+      var yamlWriterQuoted = YAMLWriter(allowUnquotedStrings: false);
+
+      var yaml2 = yamlWriterQuoted.write(tree);
+
+      print(yaml2);
+
+      expect(yaml2, equals(r'''
+foo: 
+  s1: 'Unquoted string with some@email and a /path/file.'
+  s2: 'Quoted $string.'
+  s3: '@Quoted string.'
+  s4: '-Quoted string.'
+  s5: 'UnQuoted@string.'
+  s6: 'UnQuoted-string.'
+'''));
+    });
+
+    test('indent 1', () {
+      var yamlWriter = YAMLWriter(indentSize: 1);
+
+      var tree = {
+        'foo': {
+          's1': 'Some string',
+        }
+      };
+
+      var yaml = yamlWriter.write(tree);
+
+      print(yaml);
+
+      expect(yaml, equals(r'''
+foo: 
+ s1: 'Some string'
+'''));
+    });
+
+    test('indent 5', () {
+      var yamlWriter = YAMLWriter(indentSize: 5);
+
+      var tree = {
+        'foo': {
+          's1': 'Some string',
+        }
+      };
+
+      var yaml = yamlWriter.write(tree);
+
+      print(yaml);
+
+      expect(yaml, equals(r'''
+foo: 
+     s1: 'Some string'
+'''));
+    });
+
+    test('@deprecated identSize 8', () {
+      // ignore: deprecated_member_use_from_same_package
+      var yamlWriter = YAMLWriter(identSize: 3);
+
+      var tree = {
+        'foo': {
+          's1': 'Some string',
+        }
+      };
+
+      var yaml = yamlWriter.write(tree);
+
+      print(yaml);
+
+      expect(yaml, equals(r'''
+foo: 
+   s1: 'Some string'
+'''));
+    });
+
     test('list', () {
       var yamlWriter = YAMLWriter();
 
diff --git a/yaml_writer.iml b/yaml_writer.iml
index da93800..a7a886f 100644
--- a/yaml_writer.iml
+++ b/yaml_writer.iml
@@ -1,13 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<module type="WEB_MODULE" version="4">
+<module type="JAVA_MODULE" version="4">
   <component name="NewModuleRootManager" inherit-compiler-output="true">
     <exclude-output />
     <content url="file://$MODULE_DIR$">
-      <excludeFolder url="file://$MODULE_DIR$/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
       <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
-      <excludeFolder url="file://$MODULE_DIR$/coverage" />
     </content>
+    <orderEntry type="inheritedJdk" />
     <orderEntry type="sourceFolder" forTests="false" />
     <orderEntry type="library" name="Dart SDK" level="project" />
     <orderEntry type="library" name="Dart Packages" level="project" />