diff --git a/README.md b/README.md
index cf88e4c..04a6b13 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@
 Transfer Object Generator
 ==========================
 
-Would you like to build Transfer Objects (TO) easily?
+Would you like to build lightweight Transfer Objects (TO) easily?
 You're in the right place!
 
 Build TOs Using an Array as Blueprint
@@ -22,7 +22,7 @@ $data = [
 ];
 ```
 
-then facade method converts array into `YML` definition file:
+TO facade method helps to convert array into `YML` definition file:
 ```yml
 Customer:
   firstName:
@@ -31,7 +31,7 @@ Customer:
     type: string
 ```
 
-finally console command generates TO:
+Generator console command builds TO based on definition file:
 ```php
 $customerTransfer = new CustomerTransfer();
 $customerTransfer->firstName = 'Jan';
@@ -39,8 +39,19 @@ $customerTransfer->lastName = 'Kowalski';
 ```
 
 How it works in action can be found on Wiki:
- - [Try Sample with Array](/doc/samples/try-definition-generator.php)
- - [Try Sample with YML Definition](/doc/samples/try-transfer-generator.php)
+ - [Try Sample to generate Definition files](/doc/samples/try-definition-generator.php)
+ - [Try Sample to generate TOs](/doc/samples/try-transfer-generator.php)
+ - [Try Advanced Sample to generate TOs](/doc/samples/try-advanced-transfer-generator.php)
+
+Key Features
+------------
+
+* **Interface methods:** implements `fromArray()`, `toArray()`
+* **Standard interfaces:** implements `IteratorAggregate`, `JsonSerializable`, and `Countable`
+* **Lightweight:** TO includes only data without any business logic
+* **Nullable:** supports both attribute types nullable and not nullable (`required:`)
+* **BackedEnum:** supports `BackedEnum`
+* **Adaptable:** compatible with custom Data Transfer Object (DTO) implementation
 
 Installation
 ------------
@@ -48,17 +59,15 @@ Installation
 Composer installation:
 
 ```shell
-$ composer require-dev picamator/transfer-object
+$ composer require picamator/transfer-object
 ```
 
 Usage
 -----
 
-Transfer Object (TO) generator can be used in two ways:
-
-### I. Via Terminal
+### Terminal
 
-Run command bellow, specifying your configuration file:
+Run command bellow to generate Transfer Objects:
 
 ```shell
 $ ./vendor/bin/generate-transfer [-c|--configuration CONFIGURATION]
@@ -68,9 +77,10 @@ Please check Wiki for more details:
 - [Command Configuration](https://github.com/picamator/transfer-object/wiki/Command-Configuration)
 - [Definition File](https://github.com/picamator/transfer-object/wiki/Definition-File)
 
-### II. Via Facade Interface
+### Facade Interface
 
-Directly call facade interfaces `TransferGeneratorFacadeInterface`, `DefinitionGeneratorFacadeInterface`.
+Facade interface `DefinitionGeneratorFacadeInterface` is used to generate `YML` definition file
+based on array.
 
 Please check Wiki for more details:
 - [Facade Interfaces](https://github.com/picamator/transfer-object/wiki/Facade-Interfaces)
@@ -79,8 +89,7 @@ Please check Wiki for more details:
 Acknowledgment
 --------------
 
-Many thanks to everyone for you contribution, supports and feedback!
-Have fun with using Transfer Object generator!
+Many thanks for your contribution, supports, feedback and simply using Transfer Object Generator!
 
 Contribution
 ------------
diff --git a/SECURITY.md b/SECURITY.md
index 078a2f6..56231de 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -4,11 +4,10 @@ Security Policy
 Reporting a Vulnerability
 -------------------------
 
-When you found an security vulnerability on Transfer Object Generator,
-please report it by private message to one of project's maintainer using
-any publicly available maintainer GitHub profile.
+If you discover a security vulnerability in the Transfer Object Generator, please report it privately to one of the project's maintainers.
+You can reach them through their GitHub profiles contact data.
 
 ### Important note
 
-Please don't report security issues in publicly available way neither via GitHub issues
-nor discussions or pull requests.
+Please do not report security issues through public channels such as GitHub issues, discussions, or pull requests.
+This ensures that security vulnerabilities are addressed quicky and do not pose a risk to users.
diff --git a/composer.json b/composer.json
index 7100042..b95a9f8 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
   "name": "picamator/transfer-object",
   "description": "Transfer Object Generator based on property hooks and FixedArray.",
-  "keywords": ["generator", "code generator", "data transfer object", "dto", "dev"],
+  "keywords": ["generator", "code generator", "data transfer object", "dto"],
   "license": "MIT",
   "authors": [
     {
diff --git a/config/definition/transfer-generator.transfer.yml b/config/definition/transfer-generator.transfer.yml
index 7b821e5..d6fb1bb 100644
--- a/config/definition/transfer-generator.transfer.yml
+++ b/config/definition/transfer-generator.transfer.yml
@@ -57,6 +57,8 @@ DefinitionProperty:
   isNullable:
     type: bool
     required:
+  namespace:
+    type: string
 
 DefinitionValidator:
   isValid:
diff --git a/doc/samples/Advanced/CredentialsData.php b/doc/samples/Advanced/CredentialsData.php
new file mode 100644
index 0000000..75a1968
--- /dev/null
+++ b/doc/samples/Advanced/CredentialsData.php
@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Doc\Samples\TransferObject\Advanced;
+
+use Picamator\TransferObject\Transfer\DummyTransferAdapterTrait;
+use Picamator\TransferObject\Transfer\TransferInterface;
+
+class CredentialsData implements TransferInterface
+{
+    use DummyTransferAdapterTrait;
+
+    public string $login {
+        get => $this->login;
+        set => $this->login = $value;
+    }
+
+    public string $token {
+        get => $this->token;
+        set => $this->token = $value;
+    }
+}
diff --git a/doc/samples/Generated/AdvancedTransferGenerator/AdvancedCustomerTransfer.php b/doc/samples/Generated/AdvancedTransferGenerator/AdvancedCustomerTransfer.php
new file mode 100644
index 0000000..c434cff
--- /dev/null
+++ b/doc/samples/Generated/AdvancedTransferGenerator/AdvancedCustomerTransfer.php
@@ -0,0 +1,53 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Doc\Samples\TransferObject\Generated\AdvancedTransferGenerator;
+
+use Picamator\Doc\Samples\TransferObject\Advanced\CredentialsData;
+use Picamator\Doc\Samples\TransferObject\Generated\TransferGenerator\CustomerTransfer;
+use Picamator\TransferObject\Transfer\AbstractTransfer;
+use Picamator\TransferObject\Transfer\Attribute\PropertyTypeAttribute;
+use Picamator\TransferObject\Transfer\TransferInterface;
+use Picamator\TransferObject\Transfer\TransferTrait;
+
+/**
+ * Specification:
+ * - Class is automatically generated based on a definition file.
+ * - To modify it, please update corresponding definition file and run generator again.
+ *
+ * Note: Do not manually edit this file, as changes will be overwritten.
+ */
+final class AdvancedCustomerTransfer extends AbstractTransfer
+{
+    use TransferTrait;
+
+    protected const int META_DATA_SIZE = 2;
+
+    protected const array META_DATA = [
+        self::CREDENTIALS => self::CREDENTIALS_DATA_NAME,
+        self::CUSTOMER => self::CUSTOMER_DATA_NAME,
+    ];
+
+    // credentials
+    #[PropertyTypeAttribute(CredentialsData::class)]
+    public const string CREDENTIALS = 'credentials';
+    protected const string CREDENTIALS_DATA_NAME = 'CREDENTIALS';
+    protected const int CREDENTIALS_DATA_INDEX = 0;
+
+    public TransferInterface&CredentialsData $credentials {
+        get => $this->getData(self::CREDENTIALS_DATA_INDEX);
+        set => $this->setData(self::CREDENTIALS_DATA_INDEX, $value);
+    }
+
+    // customer
+    #[PropertyTypeAttribute(CustomerTransfer::class)]
+    public const string CUSTOMER = 'customer';
+    protected const string CUSTOMER_DATA_NAME = 'CUSTOMER';
+    protected const int CUSTOMER_DATA_INDEX = 1;
+
+    public TransferInterface&CustomerTransfer $customer {
+        get => $this->getData(self::CUSTOMER_DATA_INDEX);
+        set => $this->setData(self::CUSTOMER_DATA_INDEX, $value);
+    }
+}
diff --git a/doc/samples/config/advanced-transfer-generator/definition/advanced-customer.transfer.yml b/doc/samples/config/advanced-transfer-generator/definition/advanced-customer.transfer.yml
new file mode 100644
index 0000000..eca2875
--- /dev/null
+++ b/doc/samples/config/advanced-transfer-generator/definition/advanced-customer.transfer.yml
@@ -0,0 +1,5 @@
+AdvancedCustomer:
+  customer:
+    type: "Picamator\\Doc\\Samples\\TransferObject\\Generated\\TransferGenerator\\CustomerTransfer"
+  credentials:
+    type: "Picamator\\Doc\\Samples\\TransferObject\\Advanced\\CredentialsData"
diff --git a/doc/samples/config/advanced-transfer-generator/generator.config.yml b/doc/samples/config/advanced-transfer-generator/generator.config.yml
new file mode 100644
index 0000000..812a8e1
--- /dev/null
+++ b/doc/samples/config/advanced-transfer-generator/generator.config.yml
@@ -0,0 +1,4 @@
+generator:
+  transferNamespace: "Picamator\\Doc\\Samples\\TransferObject\\Generated\\AdvancedTransferGenerator"
+  transferPath: "${PROJECT_ROOT}/doc/samples/Generated/AdvancedTransferGenerator"
+  definitionPath: "${PROJECT_ROOT}/doc/samples/config/advanced-transfer-generator/definition"
diff --git a/doc/samples/try-advanced-transfer-generator.php b/doc/samples/try-advanced-transfer-generator.php
new file mode 100644
index 0000000..6c53feb
--- /dev/null
+++ b/doc/samples/try-advanced-transfer-generator.php
@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+use Picamator\Doc\Samples\TransferObject\Advanced\CredentialsData;
+use Picamator\Doc\Samples\TransferObject\Generated\AdvancedTransferGenerator\AdvancedCustomerTransfer;
+use Picamator\Doc\Samples\TransferObject\Generated\TransferGenerator\CustomerTransfer;
+use Picamator\TransferObject\TransferGenerator\TransferGeneratorFacade;
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+echo <<<'STORY'
+=========================================================
+       How to use custom Data Transfer Object
+                        &
+      apply Transfer Object cross modules link
+=========================================================
+
+STORY;
+
+echo <<<'STORY'
+============================================================================
+         Lets take CustomerTransfer form Generated\TransferGenerator
+============================================================================
+
+STORY;
+$customerTransfer = new CustomerTransfer();
+$customerTransfer->firstName = 'Jan';
+$customerTransfer->lastName = 'Kowalski';
+
+echo <<<'STORY'
+============================================================================
+            Lets take CredentialsData form Advanced
+                             &
+       implements TransferInterface using DummyTransferAdapterTrait
+============================================================================
+
+STORY;
+$credentialsData = new CredentialsData();
+$credentialsData->login = 'jan.kowalski';
+$credentialsData->token = 'some-random-token';
+
+$encodedCredentialsData = json_encode($credentialsData);
+
+$serializedCredentialsData = serialize($credentialsData);
+$unserializedCredentialsData = unserialize($serializedCredentialsData);
+
+$iteratedCredentialsData = implode(', ', iterator_to_array($credentialsData->getIterator()));
+
+echo <<<DEBUG
+Count: {$credentialsData->count()}
+JSON encode: $encodedCredentialsData
+Serialized: $serializedCredentialsData
+Iterated: [$iteratedCredentialsData]
+
+DEBUG;
+
+echo <<<'STORY'
+===================================================================
+           Create a Definition file combining both objects
+===================================================================
+
+AdvancedCustomer:
+  customer:
+    type: 'Picamator\\Doc\\Samples\\TransferObject\\Generated\\TransferGenerator\\CustomerTransfer'
+  credentials:
+    type: 'Picamator\\Doc\\Samples\\TransferObject\\Advanced\\CredentialsData'
+
+
+STORY;
+
+echo <<<'STORY'
+======================================================
+           Generate Transfer Objects
+======================================================
+
+STORY;
+$configPath = __DIR__ . '/config/advanced-transfer-generator/generator.config.yml';
+new TransferGeneratorFacade()->generateTransfersOrFail($configPath);
+
+echo <<<'STORY'
+======================================================
+        Try newly Generated Transfer Object
+                    &
+                  Debug
+======================================================
+
+STORY;
+
+$advancedCustomerTransfer = new AdvancedCustomerTransfer();
+$advancedCustomerTransfer->customer = $customerTransfer;
+$advancedCustomerTransfer->credentials = $credentialsData;
+
+var_dump($advancedCustomerTransfer->toArray());
+
+echo <<<'STORY'
+======================================================
+                Convert fromArray
+======================================================
+
+STORY;
+$advancedCustomerTransfer = new AdvancedCustomerTransfer()->fromArray([
+    AdvancedCustomerTransfer::CUSTOMER => [
+        CustomerTransfer::FIRST_NAME => 'Max',
+        CustomerTransfer::LAST_NAME => 'Mustermann',
+    ],
+    AdvancedCustomerTransfer::CREDENTIALS => [],
+]);
+
+var_dump($advancedCustomerTransfer->toArray());
diff --git a/src/Generated/DefinitionPropertyTransfer.php b/src/Generated/DefinitionPropertyTransfer.php
index 8516bbf..d1de227 100644
--- a/src/Generated/DefinitionPropertyTransfer.php
+++ b/src/Generated/DefinitionPropertyTransfer.php
@@ -20,13 +20,14 @@ final class DefinitionPropertyTransfer extends AbstractTransfer
 {
     use TransferTrait;
 
-    protected const int META_DATA_SIZE = 6;
+    protected const int META_DATA_SIZE = 7;
 
     protected const array META_DATA = [
         self::BUILD_IN_TYPE => self::BUILD_IN_TYPE_DATA_NAME,
         self::COLLECTION_TYPE => self::COLLECTION_TYPE_DATA_NAME,
         self::ENUM_TYPE => self::ENUM_TYPE_DATA_NAME,
         self::IS_NULLABLE => self::IS_NULLABLE_DATA_NAME,
+        self::NAMESPACE => self::NAMESPACE_DATA_NAME,
         self::PROPERTY_NAME => self::PROPERTY_NAME_DATA_NAME,
         self::TRANSFER_TYPE => self::TRANSFER_TYPE_DATA_NAME,
     ];
@@ -72,10 +73,20 @@ final class DefinitionPropertyTransfer extends AbstractTransfer
         set => $this->setData(self::IS_NULLABLE_DATA_INDEX, $value);
     }
 
+    // namespace
+    public const string NAMESPACE = 'namespace';
+    protected const string NAMESPACE_DATA_NAME = 'NAMESPACE';
+    protected const int NAMESPACE_DATA_INDEX = 4;
+
+    public ?string $namespace {
+        get => $this->getData(self::NAMESPACE_DATA_INDEX);
+        set => $this->setData(self::NAMESPACE_DATA_INDEX, $value);
+    }
+
     // propertyName
     public const string PROPERTY_NAME = 'propertyName';
     protected const string PROPERTY_NAME_DATA_NAME = 'PROPERTY_NAME';
-    protected const int PROPERTY_NAME_DATA_INDEX = 4;
+    protected const int PROPERTY_NAME_DATA_INDEX = 5;
 
     public string $propertyName {
         get => $this->getRequiredData(self::PROPERTY_NAME_DATA_INDEX);
@@ -85,7 +96,7 @@ final class DefinitionPropertyTransfer extends AbstractTransfer
     // transferType
     public const string TRANSFER_TYPE = 'transferType';
     protected const string TRANSFER_TYPE_DATA_NAME = 'TRANSFER_TYPE';
-    protected const int TRANSFER_TYPE_DATA_INDEX = 5;
+    protected const int TRANSFER_TYPE_DATA_INDEX = 6;
 
     public ?string $transferType {
         get => $this->getData(self::TRANSFER_TYPE_DATA_INDEX);
diff --git a/src/Transfer/AbstractTransfer.php b/src/Transfer/AbstractTransfer.php
index 6a27aa8..5311675 100644
--- a/src/Transfer/AbstractTransfer.php
+++ b/src/Transfer/AbstractTransfer.php
@@ -9,7 +9,7 @@
 
 abstract class AbstractTransfer implements TransferInterface
 {
-    use PropertyTypeTrait;
+    use AttributeTransferTrait;
 
     protected const int META_DATA_SIZE = 0;
 
diff --git a/src/Transfer/PropertyTypeTrait.php b/src/Transfer/AttributeTransferTrait.php
similarity index 97%
rename from src/Transfer/PropertyTypeTrait.php
rename to src/Transfer/AttributeTransferTrait.php
index 025666c..55c19a7 100644
--- a/src/Transfer/PropertyTypeTrait.php
+++ b/src/Transfer/AttributeTransferTrait.php
@@ -8,7 +8,7 @@
 use ReflectionAttribute;
 use ReflectionClassConstant;
 
-trait PropertyTypeTrait
+trait AttributeTransferTrait
 {
     final protected function getConstantAttribute(string $constantName): ?PropertyTypeAttributeInterface
     {
diff --git a/src/Transfer/DummyTransferAdapterTrait.php b/src/Transfer/DummyTransferAdapterTrait.php
new file mode 100644
index 0000000..0c9de7d
--- /dev/null
+++ b/src/Transfer/DummyTransferAdapterTrait.php
@@ -0,0 +1,63 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\Transfer;
+
+use EmptyIterator;
+use Traversable;
+
+trait DummyTransferAdapterTrait
+{
+    /**
+     * @return Traversable<string, mixed>
+     */
+    public function getIterator(): Traversable
+    {
+        return new EmptyIterator();
+    }
+
+    public function count(): int
+    {
+        return 0;
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function toArray(): array
+    {
+        return [];
+    }
+
+    /**
+     * @param array<string,mixed> $data
+     */
+    public function fromArray(array $data): static
+    {
+        return $this;
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    public function jsonSerialize(): array
+    {
+        return [];
+    }
+
+    /**
+     * @return array<string,mixed>
+     */
+    final public function __serialize(): array
+    {
+        return [];
+    }
+
+    /**
+     * @param array<string,mixed> $data
+     */
+    final public function __unserialize(array $data): void
+    {
+    }
+}
diff --git a/src/TransferGenerator/Config/Validator/Content/TransferNamespaceConfigContentValidator.php b/src/TransferGenerator/Config/Validator/Content/TransferNamespaceConfigContentValidator.php
index 74be26a..65f88f9 100644
--- a/src/TransferGenerator/Config/Validator/Content/TransferNamespaceConfigContentValidator.php
+++ b/src/TransferGenerator/Config/Validator/Content/TransferNamespaceConfigContentValidator.php
@@ -6,26 +6,26 @@
 
 use Picamator\TransferObject\Generated\ConfigContentTransfer;
 use Picamator\TransferObject\Generated\ValidatorMessageTransfer;
+use Picamator\TransferObject\TransferGenerator\Validator\NamespaceValidatorTrait;
 use Picamator\TransferObject\TransferGenerator\Validator\ValidatorMessageTrait;
 
 readonly class TransferNamespaceConfigContentValidator implements ConfigContentValidatorInterface
 {
     use ValidatorMessageTrait;
-
-    private const string NAMESPACE_REGEX = '#^(?:[A-Z][a-zA-Z0-9_]*\\\\)*[A-Z][a-zA-Z0-9_]*$#';
+    use NamespaceValidatorTrait;
 
     private const string ERROR_MESSAGE_TEMPLATE = 'Invalid configuration namespace "%s".';
 
     public function validate(ConfigContentTransfer $configContentTransfer): ValidatorMessageTransfer
     {
         $namespace = $configContentTransfer->transferNamespace;
-        if (preg_match(self::NAMESPACE_REGEX, $namespace) !== 1) {
-            $errorMessage = $this->getErrorMessage($namespace);
-
-            return $this->createErrorMessageTransfer($errorMessage);
+        if ($this->isValidNamespace($namespace)) {
+            return $this->createSuccessMessageTransfer();
         }
 
-        return $this->createSuccessMessageTransfer();
+        $errorMessage = $this->getErrorMessage($namespace);
+
+        return $this->createErrorMessageTransfer($errorMessage);
     }
 
     private function getErrorMessage(string $namespace): string
diff --git a/src/TransferGenerator/Definition/DefinitionFactory.php b/src/TransferGenerator/Definition/DefinitionFactory.php
index 173785c..b63088f 100644
--- a/src/TransferGenerator/Definition/DefinitionFactory.php
+++ b/src/TransferGenerator/Definition/DefinitionFactory.php
@@ -36,6 +36,7 @@
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\CollectionTypePropertyValidator;
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\EnumTypePropertyValidator;
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\NamePropertyValidator;
+use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\NamespacePropertyValidator;
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\PropertyValidatorInterface;
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\RequiredTypePropertyValidator;
 use Picamator\TransferObject\TransferGenerator\Definition\Validator\Property\TransferTypePropertyValidator;
@@ -90,9 +91,15 @@ protected function createPropertyValidators(): ArrayObject
             $this->createTransferTypePropertyValidator(),
             $this->createCollectionTypePropertyValidator(),
             $this->createEnumTypePropertyValidator(),
+            $this->createNamespacePropertyValidator(),
         ]);
     }
 
+    protected function createNamespacePropertyValidator(): PropertyValidatorInterface
+    {
+        return new NamespacePropertyValidator();
+    }
+
     protected function createEnumTypePropertyValidator(): PropertyValidatorInterface
     {
         return new EnumTypePropertyValidator();
diff --git a/src/TransferGenerator/Definition/Enum/TypePrefixEnum.php b/src/TransferGenerator/Definition/Enum/TypePrefixEnum.php
new file mode 100644
index 0000000..e7c7037
--- /dev/null
+++ b/src/TransferGenerator/Definition/Enum/TypePrefixEnum.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\TransferGenerator\Definition\Enum;
+
+enum TypePrefixEnum: string
+{
+    case TRANSFER = 'Transfer';
+}
diff --git a/src/TransferGenerator/Definition/Parser/ContentBuilder.php b/src/TransferGenerator/Definition/Parser/ContentBuilder.php
index a655f03..c872d1e 100644
--- a/src/TransferGenerator/Definition/Parser/ContentBuilder.php
+++ b/src/TransferGenerator/Definition/Parser/ContentBuilder.php
@@ -7,6 +7,7 @@
 use ArrayObject;
 use Picamator\TransferObject\Generated\DefinitionContentTransfer;
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
+use Picamator\TransferObject\TransferGenerator\Definition\Enum\TypePrefixEnum;
 use Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander\PropertyExpanderInterface;
 
 readonly class ContentBuilder implements ContentBuilderInterface
@@ -22,7 +23,7 @@ public function __construct(
     public function createContentTransfer(string $className, array $properties): DefinitionContentTransfer
     {
         $contentTransfer = new DefinitionContentTransfer();
-        $contentTransfer->className = $className;
+        $contentTransfer->className = $className . TypePrefixEnum::TRANSFER->value;
 
         foreach ($properties as $propertyName => $propertyType) {
             $propertyType = is_array($propertyType) ? $propertyType : [];
diff --git a/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
index 7033689..8ae38f5 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/CollectionTypePropertyExpander.php
@@ -5,9 +5,12 @@
 namespace Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander;
 
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
+use Picamator\TransferObject\TransferGenerator\Definition\Enum\TypePrefixEnum;
 
 readonly class CollectionTypePropertyExpander implements PropertyExpanderInterface
 {
+    use NamespacePropertyExpanderTrait;
+
     private const string COLLECTION_TYPE_KEY = 'collectionType';
 
     public function isApplicable(array $propertyType): bool
@@ -22,7 +25,15 @@ public function isNextAllowed(): false
 
     public function expandPropertyTransfer(array $propertyType, DefinitionPropertyTransfer $propertyTransfer): void
     {
-        $propertyTransfer->collectionType = $this->getCollectionType($propertyType);
+        $collectionType = $this->getCollectionType($propertyType) ?: '';
+        if (!$this->isNamespace($collectionType)) {
+            $propertyTransfer->collectionType = $collectionType . TypePrefixEnum::TRANSFER->value;
+
+            return;
+        }
+
+        $propertyTransfer->namespace = $collectionType;
+        $propertyTransfer->collectionType = $this->getClassName($collectionType);
     }
 
     /**
diff --git a/src/TransferGenerator/Definition/Parser/Expander/NamespacePropertyExpanderTrait.php b/src/TransferGenerator/Definition/Parser/Expander/NamespacePropertyExpanderTrait.php
new file mode 100644
index 0000000..3388b94
--- /dev/null
+++ b/src/TransferGenerator/Definition/Parser/Expander/NamespacePropertyExpanderTrait.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander;
+
+trait NamespacePropertyExpanderTrait
+{
+    private const string NAMESPACE_ALIAS_SEPARATOR = ' as ';
+
+    protected function isNamespace(string $propertyName): bool
+    {
+        return str_contains($propertyName, '\\');
+    }
+
+    protected function getClassName(string $namespace): string
+    {
+        $alias = $this->getNamespaceAlias($namespace);
+        if ($alias !== null) {
+            return $alias;
+        }
+
+        /** @var string $className */
+        $className = strrchr($namespace, '\\');
+
+        return ltrim($className, '\\');
+    }
+
+    private function getNamespaceAlias(string $namespace): ?string
+    {
+        if (!str_contains($namespace, self::NAMESPACE_ALIAS_SEPARATOR)) {
+            return null;
+        }
+
+        /** @var string $alias */
+        $alias = strrchr($namespace, self::NAMESPACE_ALIAS_SEPARATOR);
+
+        return trim($alias);
+    }
+}
diff --git a/src/TransferGenerator/Definition/Parser/Expander/TransferTypePropertyExpander.php b/src/TransferGenerator/Definition/Parser/Expander/TransferTypePropertyExpander.php
index a94fc96..92a588f 100644
--- a/src/TransferGenerator/Definition/Parser/Expander/TransferTypePropertyExpander.php
+++ b/src/TransferGenerator/Definition/Parser/Expander/TransferTypePropertyExpander.php
@@ -5,9 +5,12 @@
 namespace Picamator\TransferObject\TransferGenerator\Definition\Parser\Expander;
 
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
+use Picamator\TransferObject\TransferGenerator\Definition\Enum\TypePrefixEnum;
 
 readonly class TransferTypePropertyExpander implements PropertyExpanderInterface
 {
+    use NamespacePropertyExpanderTrait;
+
     private const string TYPE_KEY = 'type';
 
     public function isApplicable(array $propertyType): bool
@@ -22,7 +25,15 @@ public function isNextAllowed(): false
 
     public function expandPropertyTransfer(array $propertyType, DefinitionPropertyTransfer $propertyTransfer): void
     {
-        $propertyTransfer->transferType = $this->getTransferType($propertyType);
+        $transferType = $this->getTransferType($propertyType) ?: '';
+        if (!$this->isNamespace($transferType)) {
+            $propertyTransfer->transferType = $transferType . TypePrefixEnum::TRANSFER->value;
+
+            return;
+        }
+
+        $propertyTransfer->namespace = $transferType;
+        $propertyTransfer->transferType = $this->getClassName($transferType);
     }
 
     /**
diff --git a/src/TransferGenerator/Definition/Validator/ClassNameValidator.php b/src/TransferGenerator/Definition/Validator/ClassNameValidator.php
index 9e381cb..b29cdac 100644
--- a/src/TransferGenerator/Definition/Validator/ClassNameValidator.php
+++ b/src/TransferGenerator/Definition/Validator/ClassNameValidator.php
@@ -6,6 +6,7 @@
 
 use Picamator\TransferObject\Generated\ValidatorMessageTransfer;
 use Picamator\TransferObject\TransferGenerator\Validator\ValidatorMessageTrait;
+use Picamator\TransferObject\TransferGenerator\Validator\VariableValidatorTrait;
 
 readonly class ClassNameValidator implements ClassNameValidatorInterface
 {
diff --git a/src/TransferGenerator/Definition/Validator/Property/BuildInTypePropertyValidator.php b/src/TransferGenerator/Definition/Validator/Property/BuildInTypePropertyValidator.php
index 6a51295..a4d2963 100644
--- a/src/TransferGenerator/Definition/Validator/Property/BuildInTypePropertyValidator.php
+++ b/src/TransferGenerator/Definition/Validator/Property/BuildInTypePropertyValidator.php
@@ -12,8 +12,7 @@
 {
     use ValidatorMessageTrait;
 
-    private const string UNSUPPORTED_PROPERTY_TYPE_ERROR_MESSAGE_TEMPLATE
-        = 'Property "%s" with type "%s" is not supported.';
+    private const string UNSUPPORTED_TYPE_ERROR_MESSAGE_TEMPLATE = 'Property "%s" with type "%s" is not supported.';
 
     public function isApplicable(DefinitionPropertyTransfer $propertyTransfer): bool
     {
@@ -34,7 +33,7 @@ public function validate(DefinitionPropertyTransfer $propertyTransfer): Validato
     private function getErrorMessage(DefinitionPropertyTransfer $propertyTransfer): string
     {
         return sprintf(
-            self::UNSUPPORTED_PROPERTY_TYPE_ERROR_MESSAGE_TEMPLATE,
+            self::UNSUPPORTED_TYPE_ERROR_MESSAGE_TEMPLATE,
             $propertyTransfer->propertyName,
             $propertyTransfer->buildInType->value ?? '',
         );
diff --git a/src/TransferGenerator/Definition/Validator/Property/NamePropertyValidator.php b/src/TransferGenerator/Definition/Validator/Property/NamePropertyValidator.php
index 3f27e0b..99f2d20 100644
--- a/src/TransferGenerator/Definition/Validator/Property/NamePropertyValidator.php
+++ b/src/TransferGenerator/Definition/Validator/Property/NamePropertyValidator.php
@@ -6,15 +6,15 @@
 
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
 use Picamator\TransferObject\Generated\ValidatorMessageTransfer;
-use Picamator\TransferObject\TransferGenerator\Definition\Validator\VariableValidatorTrait;
 use Picamator\TransferObject\TransferGenerator\Validator\ValidatorMessageTrait;
+use Picamator\TransferObject\TransferGenerator\Validator\VariableValidatorTrait;
 
 readonly class NamePropertyValidator implements PropertyValidatorInterface
 {
     use VariableValidatorTrait;
     use ValidatorMessageTrait;
 
-    private const string INVALID_PROPERTY_NAME_ERROR_MESSAGE_TEMPLATE = 'Invalid property name "%s".';
+    private const string INVALID_NAME_ERROR_MESSAGE_TEMPLATE = 'Invalid property name "%s".';
 
     public function isApplicable(DefinitionPropertyTransfer $propertyTransfer): true
     {
@@ -35,7 +35,7 @@ public function validate(DefinitionPropertyTransfer $propertyTransfer): Validato
     private function getErrorMessage(DefinitionPropertyTransfer $propertyTransfer): string
     {
         return sprintf(
-            self::INVALID_PROPERTY_NAME_ERROR_MESSAGE_TEMPLATE,
+            self::INVALID_NAME_ERROR_MESSAGE_TEMPLATE,
             $propertyTransfer->propertyName,
         );
     }
diff --git a/src/TransferGenerator/Definition/Validator/Property/NamespacePropertyValidator.php b/src/TransferGenerator/Definition/Validator/Property/NamespacePropertyValidator.php
new file mode 100644
index 0000000..2174b3a
--- /dev/null
+++ b/src/TransferGenerator/Definition/Validator/Property/NamespacePropertyValidator.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\TransferGenerator\Definition\Validator\Property;
+
+use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
+use Picamator\TransferObject\Generated\ValidatorMessageTransfer;
+use Picamator\TransferObject\TransferGenerator\Validator\NamespaceValidatorTrait;
+use Picamator\TransferObject\TransferGenerator\Validator\ValidatorMessageTrait;
+
+readonly class NamespacePropertyValidator implements PropertyValidatorInterface
+{
+    use ValidatorMessageTrait;
+    use NamespaceValidatorTrait;
+
+    private const string NAMESPACE_ALIAS_SEPARATOR = ' as ';
+
+    private const string INVALID_NAMESPACE_ERROR_MESSAGE_TEMPLATE = 'Invalid property namespace "%s".';
+
+    public function isApplicable(DefinitionPropertyTransfer $propertyTransfer): bool
+    {
+        return $propertyTransfer->namespace !== null;
+    }
+
+    public function validate(DefinitionPropertyTransfer $propertyTransfer): ValidatorMessageTransfer
+    {
+        $namespace = $this->getNamespaceWithoutAlias($propertyTransfer);
+        if ($this->isValidNamespace($namespace)) {
+            return $this->createSuccessMessageTransfer();
+        }
+
+        $errorMessage = $this->getErrorMessage($propertyTransfer);
+
+        return $this->createErrorMessageTransfer($errorMessage);
+    }
+
+    private function getErrorMessage(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        return sprintf(
+            self::INVALID_NAMESPACE_ERROR_MESSAGE_TEMPLATE,
+            $propertyTransfer->namespace ?: '',
+        );
+    }
+
+    private function getNamespaceWithoutAlias(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        $namespace = $propertyTransfer->namespace ?: '';
+        if (!str_contains($namespace, self::NAMESPACE_ALIAS_SEPARATOR)) {
+            return $namespace;
+        }
+
+        /** @var string $namespace */
+        $namespace = strstr($namespace, self::NAMESPACE_ALIAS_SEPARATOR, true);
+
+        return trim($namespace);
+    }
+}
diff --git a/src/TransferGenerator/Generator/Enum/TransferEnum.php b/src/TransferGenerator/Generator/Enum/TransferEnum.php
index 3e65480..e16e6f3 100644
--- a/src/TransferGenerator/Generator/Enum/TransferEnum.php
+++ b/src/TransferGenerator/Generator/Enum/TransferEnum.php
@@ -5,10 +5,12 @@
 namespace Picamator\TransferObject\TransferGenerator\Generator\Enum;
 
 use Picamator\TransferObject\Transfer\AbstractTransfer;
+use Picamator\TransferObject\Transfer\TransferInterface;
 use Picamator\TransferObject\Transfer\TransferTrait;
 
 enum TransferEnum: string
 {
+    case INTERFACE = TransferInterface::class;
     case ABSTRACT_CLASS = AbstractTransfer::class;
     case TRAIT = TransferTrait::class;
 }
diff --git a/src/TransferGenerator/Generator/Filesystem/GeneratorFilesystem.php b/src/TransferGenerator/Generator/Filesystem/GeneratorFilesystem.php
index 26d9e97..55a580b 100644
--- a/src/TransferGenerator/Generator/Filesystem/GeneratorFilesystem.php
+++ b/src/TransferGenerator/Generator/Filesystem/GeneratorFilesystem.php
@@ -13,7 +13,7 @@
 {
     private const string TEMPORARY_DIR = '_tmp';
 
-    private const string FILE_NAME_TEMPLATE = '%sTransfer.php';
+    private const string FILE_EXTENSION = '.php';
     private const string FILE_NAME_PATTERN = '*Transfer.php';
 
     public function __construct(
@@ -51,9 +51,7 @@ public function rotateTempDir(): void
 
     public function writeFile(string $className, string $content): void
     {
-        $filePath = $this->getTemporaryPath()
-            . DIRECTORY_SEPARATOR
-            . sprintf(self::FILE_NAME_TEMPLATE, $className);
+        $filePath = $this->getTemporaryPath() . DIRECTORY_SEPARATOR . $className . self::FILE_EXTENSION;
         if ($this->filesystem->exists($filePath)) {
             throw new TransferGeneratorException(
                 sprintf('Cannot save file "%s". A file with the same name already exists.', $filePath),
diff --git a/src/TransferGenerator/Generator/Render/Expander/BuildInTypeTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/BuildInTypeTemplateExpander.php
index 0d13983..b1ed445 100644
--- a/src/TransferGenerator/Generator/Render/Expander/BuildInTypeTemplateExpander.php
+++ b/src/TransferGenerator/Generator/Render/Expander/BuildInTypeTemplateExpander.php
@@ -8,14 +8,11 @@
 use Picamator\TransferObject\TransferGenerator\Generator\Enum\AttributeEnum;
 use Picamator\TransferObject\TransferGenerator\Generator\Enum\AttributeTemplateEnum;
 use Picamator\TransferObject\TransferGenerator\Generator\Enum\DockBlockTemplateEnum;
-use Picamator\TransferObject\TransferGenerator\Generator\Render\TemplateRenderTrait;
 use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
 use Picamator\TransferObject\Generated\TemplateTransfer;
 
 readonly class BuildInTypeTemplateExpander implements TemplateExpanderInterface
 {
-    use TemplateRenderTrait;
-
     public function isApplicable(DefinitionPropertyTransfer $propertyTransfer): bool
     {
         return $propertyTransfer->buildInType !== null;
diff --git a/src/TransferGenerator/Generator/Render/Expander/CollectionTypeTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/CollectionTypeTemplateExpander.php
index 9cf9a1f..602b21e 100644
--- a/src/TransferGenerator/Generator/Render/Expander/CollectionTypeTemplateExpander.php
+++ b/src/TransferGenerator/Generator/Render/Expander/CollectionTypeTemplateExpander.php
@@ -29,16 +29,27 @@ public function expandTemplateTransfer(
         $templateTransfer->imports[AttributeEnum::COLLECTION_TYPE_ATTRIBUTE->value]
             ??= AttributeEnum::COLLECTION_TYPE_ATTRIBUTE->value;
 
-        $transferName = $this->getTransferName($propertyTransfer->collectionType ?: '');
-
         $propertyName = $propertyTransfer->propertyName;
         $templateTransfer->properties[$propertyName] = BuildInTypeEnum::ARRAY_OBJECT->value;
-        $templateTransfer->attributes[$propertyName] = sprintf(
-            AttributeTemplateEnum::COLLECTION_TYPE_ATTRIBUTE->value,
-            $transferName,
-        );
-        $templateTransfer->dockBlocks[$propertyName] = sprintf(DockBlockTemplateEnum::COLLECTION->value, $transferName);
-
+        $templateTransfer->attributes[$propertyName] = $this->getPropertyAttribute($propertyTransfer);
+        $templateTransfer->dockBlocks[$propertyName] = $this->getPropertyDockBlock($propertyTransfer);
         $templateTransfer->nullables[$propertyName] = false;
     }
+
+    private function getPropertyDockBlock(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        $propertyType = $propertyTransfer->collectionType ?: '';
+        if ($propertyTransfer->namespace !== null) {
+            $propertyType = $this->enforceTransferInterface($propertyType);
+        }
+
+        return sprintf(DockBlockTemplateEnum::COLLECTION->value, $propertyType);
+    }
+
+    private function getPropertyAttribute(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        $transferType = $propertyTransfer->collectionType ?: '';
+
+        return sprintf(AttributeTemplateEnum::COLLECTION_TYPE_ATTRIBUTE->value, $transferType);
+    }
 }
diff --git a/src/TransferGenerator/Generator/Render/Expander/EnumTypeTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/EnumTypeTemplateExpander.php
index 2a927f3..89c3b10 100644
--- a/src/TransferGenerator/Generator/Render/Expander/EnumTypeTemplateExpander.php
+++ b/src/TransferGenerator/Generator/Render/Expander/EnumTypeTemplateExpander.php
@@ -30,14 +30,15 @@ public function expandTemplateTransfer(
         $enumClassName = $this->getEnumName($propertyTransfer);
 
         $templateTransfer->properties[$propertyName] = $enumClassName;
-        $templateTransfer->attributes[$propertyName] = sprintf(
-            AttributeTemplateEnum::ENUM_TYPE_ATTRIBUTE->value,
-            $enumClassName,
-        );
-
+        $templateTransfer->attributes[$propertyName] = $this->getPropertyAttribute($enumClassName);
         $templateTransfer->nullables[$propertyName] = $propertyTransfer->isNullable;
     }
 
+    private function getPropertyAttribute(string $enumClassName): string
+    {
+        return sprintf(AttributeTemplateEnum::ENUM_TYPE_ATTRIBUTE->value, $enumClassName);
+    }
+
     private function getEnumName(DefinitionPropertyTransfer $propertyTransfer): string
     {
         $enumName = $propertyTransfer->enumType ?? '';
diff --git a/src/TransferGenerator/Generator/Render/Expander/NamespaceTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/NamespaceTemplateExpander.php
new file mode 100644
index 0000000..63dfbb6
--- /dev/null
+++ b/src/TransferGenerator/Generator/Render/Expander/NamespaceTemplateExpander.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\TransferGenerator\Generator\Render\Expander;
+
+use Picamator\TransferObject\TransferGenerator\Generator\Enum\TransferEnum;
+use Picamator\TransferObject\TransferGenerator\Generator\Render\TemplateRenderTrait;
+use Picamator\TransferObject\Generated\DefinitionPropertyTransfer;
+use Picamator\TransferObject\Generated\TemplateTransfer;
+
+readonly class NamespaceTemplateExpander implements TemplateExpanderInterface
+{
+    use TemplateRenderTrait;
+
+    public function isApplicable(DefinitionPropertyTransfer $propertyTransfer): bool
+    {
+        return $propertyTransfer->namespace !== null;
+    }
+
+    public function expandTemplateTransfer(
+        DefinitionPropertyTransfer $propertyTransfer,
+        TemplateTransfer $templateTransfer,
+    ): void {
+        $templateTransfer->imports[$propertyTransfer->namespace] ??= $propertyTransfer->namespace;
+        $templateTransfer->imports[TransferEnum::INTERFACE->value] ??= TransferEnum::INTERFACE->value;
+    }
+}
diff --git a/src/TransferGenerator/Generator/Render/Expander/TransferTypeTemplateExpander.php b/src/TransferGenerator/Generator/Render/Expander/TransferTypeTemplateExpander.php
index 8bbdbec..4244da7 100644
--- a/src/TransferGenerator/Generator/Render/Expander/TransferTypeTemplateExpander.php
+++ b/src/TransferGenerator/Generator/Render/Expander/TransferTypeTemplateExpander.php
@@ -25,15 +25,26 @@ public function expandTemplateTransfer(
     ): void {
         $templateTransfer->imports[AttributeEnum::TYPE_ATTRIBUTE->value] ??= AttributeEnum::TYPE_ATTRIBUTE->value;
 
-        $transferName = $this->getTransferName($propertyTransfer->transferType ?: '');
         $propertyName = $propertyTransfer->propertyName;
+        $templateTransfer->properties[$propertyName] = $this->getPropertyType($propertyTransfer);
+        $templateTransfer->attributes[$propertyName] = $this->getPropertyAttribute($propertyTransfer);
+        $templateTransfer->nullables[$propertyName] = $propertyTransfer->isNullable;
+    }
 
-        $templateTransfer->properties[$propertyName] = $transferName;
-        $templateTransfer->attributes[$propertyName] = sprintf(
-            AttributeTemplateEnum::TYPE_ATTRIBUTE->value,
-            $transferName,
-        );
+    private function getPropertyAttribute(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        $transferType = $propertyTransfer->transferType ?: '';
 
-        $templateTransfer->nullables[$propertyName] = $propertyTransfer->isNullable;
+        return sprintf(AttributeTemplateEnum::TYPE_ATTRIBUTE->value, $transferType);
+    }
+
+    private function getPropertyType(DefinitionPropertyTransfer $propertyTransfer): string
+    {
+        $transferType = $propertyTransfer->transferType ?: '';
+        if ($propertyTransfer->namespace === null) {
+            return $transferType;
+        }
+
+        return $this->enforceTransferInterface($transferType);
     }
 }
diff --git a/src/TransferGenerator/Generator/Render/Template/TemplateHelper.php b/src/TransferGenerator/Generator/Render/Template/TemplateHelper.php
index 1847f61..c089315 100644
--- a/src/TransferGenerator/Generator/Render/Template/TemplateHelper.php
+++ b/src/TransferGenerator/Generator/Render/Template/TemplateHelper.php
@@ -16,7 +16,8 @@
 
     private const string PADDING_LEFT = '    ';
     private const string EMPTY_STRING = '';
-    private const string NULLABLE_SIGN = '?';
+    private const string NULLABLE_TYPE = '?';
+    private const string NULLABLE_UNION = 'null|';
     private const string REQUIRED_METHOD_NAME = 'Required';
 
     public function __construct(private TemplateTransfer $templateTransfer)
@@ -72,7 +73,16 @@ public function getDockBlock(string $property): string
 
     public function getNullable(string $property): string
     {
-        return $this->templateTransfer->nullables[$property] ? self::NULLABLE_SIGN : self::EMPTY_STRING;
+        $propertyType = $this->templateTransfer->properties[$property];
+        if (!$this->templateTransfer->nullables[$property] || str_contains($propertyType, '&')) {
+            return self::EMPTY_STRING;
+        }
+
+        if (str_contains($propertyType, '|')) {
+            return self::NULLABLE_UNION;
+        }
+
+        return self::NULLABLE_TYPE;
     }
 
     public function getRequired(string $property): string
diff --git a/src/TransferGenerator/Generator/Render/TemplateBuilder.php b/src/TransferGenerator/Generator/Render/TemplateBuilder.php
index 3eb8d8d..76d3472 100644
--- a/src/TransferGenerator/Generator/Render/TemplateBuilder.php
+++ b/src/TransferGenerator/Generator/Render/TemplateBuilder.php
@@ -29,7 +29,7 @@ public function createTemplateTransfer(DefinitionContentTransfer $contentTransfe
     {
         $templateTransfer = new TemplateTransfer();
         $templateTransfer->classNamespace = $this->config->getTransferNamespace();
-        $templateTransfer->className = $this->getTransferName($contentTransfer->className);
+        $templateTransfer->className = $contentTransfer->className;
         $templateTransfer->imports[TransferEnum::ABSTRACT_CLASS->value] = TransferEnum::ABSTRACT_CLASS->value;
         $templateTransfer->imports[TransferEnum::TRAIT->value] = TransferEnum::TRAIT->value;
 
diff --git a/src/TransferGenerator/Generator/Render/TemplateRenderTrait.php b/src/TransferGenerator/Generator/Render/TemplateRenderTrait.php
index 48a6a0e..4eaa80a 100644
--- a/src/TransferGenerator/Generator/Render/TemplateRenderTrait.php
+++ b/src/TransferGenerator/Generator/Render/TemplateRenderTrait.php
@@ -8,8 +8,6 @@
 
 trait TemplateRenderTrait
 {
-    private const string FILE_NAME_SUFFIX = 'Transfer';
-
     private const string META_CONSTANT_REGEX = '#(?<!^)[A-Z]#';
 
     protected function sortTemplate(TemplateTransfer $templateTransfer): void
@@ -26,8 +24,8 @@ protected function getMetaConstant(string $propertyName): string
         return strtoupper($propertyName);
     }
 
-    protected function getTransferName(string $propertyType): string
+    protected function enforceTransferInterface(string $propertyType): string
     {
-        return $propertyType . self::FILE_NAME_SUFFIX;
+        return 'TransferInterface&' . $propertyType;
     }
 }
diff --git a/src/TransferGenerator/Generator/TransferGeneratorFactory.php b/src/TransferGenerator/Generator/TransferGeneratorFactory.php
index 15a0c16..db61fa4 100644
--- a/src/TransferGenerator/Generator/TransferGeneratorFactory.php
+++ b/src/TransferGenerator/Generator/TransferGeneratorFactory.php
@@ -29,6 +29,7 @@
 use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\BuildInTypeTemplateExpander;
 use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\CollectionTypeTemplateExpander;
 use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\EnumTypeTemplateExpander;
+use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\NamespaceTemplateExpander;
 use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\TemplateExpanderInterface;
 use Picamator\TransferObject\TransferGenerator\Generator\Render\Expander\TransferTypeTemplateExpander;
 use Picamator\TransferObject\TransferGenerator\Generator\Render\TemplateBuilder;
@@ -113,9 +114,15 @@ protected function createTemplateExpanders(): ArrayObject
             $this->createTransferTypeTemplateExpander(),
             $this->createBuildInTypeTemplateExpander(),
             $this->createEnumTypeTemplateExpander(),
+            $this->createNamespaceTemplateExpander(),
         ]);
     }
 
+    protected function createNamespaceTemplateExpander(): TemplateExpanderInterface
+    {
+        return new NamespaceTemplateExpander();
+    }
+
     protected function createEnumTypeTemplateExpander(): TemplateExpanderInterface
     {
         return new EnumTypeTemplateExpander();
diff --git a/src/TransferGenerator/Validator/NamespaceValidatorTrait.php b/src/TransferGenerator/Validator/NamespaceValidatorTrait.php
new file mode 100644
index 0000000..391a1b1
--- /dev/null
+++ b/src/TransferGenerator/Validator/NamespaceValidatorTrait.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\TransferObject\TransferGenerator\Validator;
+
+trait NamespaceValidatorTrait
+{
+    private const string NAMESPACE_REGEX = '#^(?:[A-Z][a-zA-Z0-9_]*\\\\)*[A-Z][a-zA-Z0-9_]*$#';
+
+    protected function isValidNamespace(?string $namespace): bool
+    {
+        return $namespace !== null && preg_match(self::NAMESPACE_REGEX, $namespace) === 1;
+    }
+}
diff --git a/src/TransferGenerator/Definition/Validator/VariableValidatorTrait.php b/src/TransferGenerator/Validator/VariableValidatorTrait.php
similarity index 80%
rename from src/TransferGenerator/Definition/Validator/VariableValidatorTrait.php
rename to src/TransferGenerator/Validator/VariableValidatorTrait.php
index dba26c4..1836825 100644
--- a/src/TransferGenerator/Definition/Validator/VariableValidatorTrait.php
+++ b/src/TransferGenerator/Validator/VariableValidatorTrait.php
@@ -2,7 +2,7 @@
 
 declare(strict_types=1);
 
-namespace Picamator\TransferObject\TransferGenerator\Definition\Validator;
+namespace Picamator\TransferObject\TransferGenerator\Validator;
 
 trait VariableValidatorTrait
 {
@@ -14,6 +14,6 @@ trait VariableValidatorTrait
 
     protected function isValidVariable(?string $variableName): bool
     {
-        return $variableName !== null && preg_match(self::VARIABLE_NAME_PATTERN, $variableName) >= 1;
+        return $variableName !== null && preg_match(self::VARIABLE_NAME_PATTERN, $variableName) === 1;
     }
 }
diff --git a/tests/integration/DefinitionGenerator/data/REFERENCE.md b/tests/integration/DefinitionGenerator/data/REFERENCE.md
index 9d7aac6..d4e7038 100644
--- a/tests/integration/DefinitionGenerator/data/REFERENCE.md
+++ b/tests/integration/DefinitionGenerator/data/REFERENCE.md
@@ -5,4 +5,4 @@ REFERENCE
 |--------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------|
 | [nasa-neo-rest-v1-neo-2465633.json](/json-samples/nasa-neo-rest-v1-neo-2465633.json) | [NASA Open Api](https://api.nasa.gov/neo/rest/v1/neo/2465633?api_key=DEMO_KEY)                                |
 | [open-weather.json](/json-samples/open-weather.json)                                 | [OpenWeather](https://openweathermap.org/current#example_JSON)                                                |
-| [google-shopping-content-api.json](/json-samples/google-shopping-content-api.json)                                 | [Content API for Shopping](https://developers.google.com/shopping-content/guides/products/products-api?hl=en) |
+| [google-shopping-content-api.json](/json-samples/google-shopping-content-api.json)   | [Content API for Shopping](https://developers.google.com/shopping-content/guides/products/products-api?hl=en) |
diff --git a/tests/integration/Samples/SamplesTest.php b/tests/integration/Samples/SamplesTest.php
index ec787cb..7fee8af 100644
--- a/tests/integration/Samples/SamplesTest.php
+++ b/tests/integration/Samples/SamplesTest.php
@@ -44,5 +44,9 @@ public static function samplesNameDataProvider(): Generator
         yield 'try-transfer-generator' => [
             'sampleName' => 'try-transfer-generator.php',
         ];
+
+        yield 'try-advanced-transfer-generator' => [
+            'sampleName' => 'try-advanced-transfer-generator.php',
+        ];
     }
 }
diff --git a/tests/integration/Transfer/Generated/NamespaceTransfer.php b/tests/integration/Transfer/Generated/NamespaceTransfer.php
new file mode 100644
index 0000000..46a0b6d
--- /dev/null
+++ b/tests/integration/Transfer/Generated/NamespaceTransfer.php
@@ -0,0 +1,56 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Tests\Integration\TransferObject\Transfer\Generated;
+
+use ArrayObject;
+use Picamator\Tests\Integration\TransferObject\Transfer\Generated\ItemTransfer;
+use Picamator\Tests\Integration\TransferObject\Transfer\Generated\RequiredTransfer as RequiredAlias;
+use Picamator\TransferObject\Transfer\AbstractTransfer;
+use Picamator\TransferObject\Transfer\Attribute\CollectionPropertyTypeAttribute;
+use Picamator\TransferObject\Transfer\Attribute\PropertyTypeAttribute;
+use Picamator\TransferObject\Transfer\TransferInterface;
+use Picamator\TransferObject\Transfer\TransferTrait;
+
+/**
+ * Specification:
+ * - Class is automatically generated based on a definition file.
+ * - To modify it, please update corresponding definition file and run generator again.
+ *
+ * Note: Do not manually edit this file, as changes will be overwritten.
+ */
+final class NamespaceTransfer extends AbstractTransfer
+{
+    use TransferTrait;
+
+    protected const int META_DATA_SIZE = 2;
+
+    protected const array META_DATA = [
+        self::ITEMS => self::ITEMS_DATA_NAME,
+        self::REQUIRED => self::REQUIRED_DATA_NAME,
+    ];
+
+    // items
+    #[CollectionPropertyTypeAttribute(ItemTransfer::class)]
+    public const string ITEMS = 'items';
+    protected const string ITEMS_DATA_NAME = 'ITEMS';
+    protected const int ITEMS_DATA_INDEX = 0;
+
+    /** @var \ArrayObject<int,TransferInterface&ItemTransfer> */
+    public ArrayObject $items {
+        get => $this->getRequiredData(self::ITEMS_DATA_INDEX);
+        set => $this->setData(self::ITEMS_DATA_INDEX, $value);
+    }
+
+    // required
+    #[PropertyTypeAttribute(RequiredAlias::class)]
+    public const string REQUIRED = 'required';
+    protected const string REQUIRED_DATA_NAME = 'REQUIRED';
+    protected const int REQUIRED_DATA_INDEX = 1;
+
+    public TransferInterface&RequiredAlias $required {
+        get => $this->getData(self::REQUIRED_DATA_INDEX);
+        set => $this->setData(self::REQUIRED_DATA_INDEX, $value);
+    }
+}
diff --git a/tests/integration/Transfer/TransferTest.php b/tests/integration/Transfer/TransferTest.php
index 67a4c13..765f76c 100644
--- a/tests/integration/Transfer/TransferTest.php
+++ b/tests/integration/Transfer/TransferTest.php
@@ -15,6 +15,7 @@
 use Picamator\Tests\Integration\TransferObject\Transfer\Enum\ImBasicEnum;
 use Picamator\Tests\Integration\TransferObject\Transfer\Generated\ItemCollectionTransfer;
 use Picamator\Tests\Integration\TransferObject\Transfer\Generated\ItemTransfer;
+use Picamator\Tests\Integration\TransferObject\Transfer\Generated\NamespaceTransfer;
 use Picamator\Tests\Integration\TransferObject\Transfer\Generated\RequiredTransfer;
 use Picamator\TransferObject\Transfer\Exception\PropertyTypeTransferException;
 use TypeError;
@@ -259,4 +260,16 @@ public function testAccessRequiredPropertyBeforeInitialisingShouldRiseException(
         // Act
         $requiredTransfer->toArray();
     }
+
+    #[Depends('testGenerateTransferShouldSucceed')]
+    public function testTypeWithNamespaceShouldSucceed(): void
+    {
+        // Arrange
+        $namespaceTransfer = new NamespaceTransfer();
+        $namespaceTransfer->items[] = new ItemTransfer();
+        $namespaceTransfer->required = new RequiredTransfer();
+
+        // Act
+        $this->assertCount(1, $namespaceTransfer->items);
+    }
 }
diff --git a/tests/integration/Transfer/data/config/definition/item.transfer.yml b/tests/integration/Transfer/data/config/definition/item.transfer.yml
index a6d27f9..742e941 100644
--- a/tests/integration/Transfer/data/config/definition/item.transfer.yml
+++ b/tests/integration/Transfer/data/config/definition/item.transfer.yml
@@ -17,5 +17,5 @@ Item:
     type: ArrayObject
   iAmEnum:
     enumType: '\Picamator\Tests\Integration\TransferObject\Transfer\Enum\ImBackedEnum'
-  data:
+  data: # property name on `AbstractTranfer`, testing collision with custom defined property
     type: array
diff --git a/tests/integration/Transfer/data/config/definition/namespace.transfer.yml b/tests/integration/Transfer/data/config/definition/namespace.transfer.yml
new file mode 100644
index 0000000..1c2fa00
--- /dev/null
+++ b/tests/integration/Transfer/data/config/definition/namespace.transfer.yml
@@ -0,0 +1,5 @@
+Namespace:
+  items:
+    collectionType: "Picamator\\Tests\\Integration\\TransferObject\\Transfer\\Generated\\ItemTransfer"
+  required:
+    type: "Picamator\\Tests\\Integration\\TransferObject\\Transfer\\Generated\\RequiredTransfer as RequiredAlias"
diff --git a/tests/integration/TransferGenerator/TransferGeneratorFacadeErrorTest.php b/tests/integration/TransferGenerator/TransferGeneratorFacadeErrorTest.php
index 5a62823..b1ccfa4 100644
--- a/tests/integration/TransferGenerator/TransferGeneratorFacadeErrorTest.php
+++ b/tests/integration/TransferGenerator/TransferGeneratorFacadeErrorTest.php
@@ -129,13 +129,23 @@ public static function invalidDefinitionDataProvider(): Generator
 
         yield 'definition file include class without properties should return error' => [
             'configCaseName' => 'empty-property-definition',
-            'expectedMessage' => 'Class "AddressStatistics" properties were not defined.',
+            'expectedMessage' => 'Class "AddressStatisticsTransfer" properties were not defined.',
         ];
 
         yield 'definitions not found should return error' => [
             'configCaseName' => 'empty-definition-directory',
             'expectedMessage' => 'Missed Transfer Object definitions.',
         ];
+
+        yield 'invalid type namespace' => [
+            'configCaseName' => 'invalid-type-namespace',
+            'expectedMessage' => 'Invalid property namespace',
+        ];
+
+        yield 'invalid type namespace with alias' => [
+            'configCaseName' => 'invalid-type-namespace-with-alias',
+            'expectedMessage' => 'Invalid property namespace',
+        ];
     }
 
     public function testBulkTransferGeneratorShouldFailOnError(): void
diff --git a/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/definition/address-statistics.transfer.yml b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/definition/address-statistics.transfer.yml
new file mode 100644
index 0000000..0741aa0
--- /dev/null
+++ b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/definition/address-statistics.transfer.yml
@@ -0,0 +1,5 @@
+AddressStatistics:
+  addressBookUuid:
+    type: "00Picamator\\Tests\\Integration\\TransferObject\\TransferGenerator\\Generated\\Success\\AddressTransfer as AliasAddress"
+  addressUuid:
+    type: string
diff --git a/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/generator.config.yml b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/generator.config.yml
new file mode 100644
index 0000000..f7777e5
--- /dev/null
+++ b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/generator.config.yml
@@ -0,0 +1,4 @@
+generator:
+  transferNamespace: "Picamator\\Tests\\Integration\\TransferObject\\TransferGenerator\\Generated\\Error"
+  transferPath: "${PROJECT_ROOT}/tests/integration/TransferGenerator/Generated/Error"
+  definitionPath: "${PROJECT_ROOT}/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace-with-alias/definition"
diff --git a/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/definition/address-statistics.transfer.yml b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/definition/address-statistics.transfer.yml
new file mode 100644
index 0000000..f14b47f
--- /dev/null
+++ b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/definition/address-statistics.transfer.yml
@@ -0,0 +1,5 @@
+AddressStatistics:
+  addressBookUuid:
+    type: "00Picamator\\Tests\\Integration\\TransferObject\\TransferGenerator\\Generated\\Success\\AddressTransfer"
+  addressUuid:
+    type: string
diff --git a/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/generator.config.yml b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/generator.config.yml
new file mode 100644
index 0000000..c5dddb1
--- /dev/null
+++ b/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/generator.config.yml
@@ -0,0 +1,4 @@
+generator:
+  transferNamespace: "Picamator\\Tests\\Integration\\TransferObject\\TransferGenerator\\Generated\\Error"
+  transferPath: "${PROJECT_ROOT}/tests/integration/TransferGenerator/Generated/Error"
+  definitionPath: "${PROJECT_ROOT}/tests/integration/TransferGenerator/data/config/error/invalid-type-namespace/definition"
diff --git a/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitInterface.php b/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderInterface.php
similarity index 87%
rename from tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitInterface.php
rename to tests/unit/DefinitionGenerator/Builder/DefinitionBuilderInterface.php
index 6bee5ff..5e99896 100644
--- a/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitInterface.php
+++ b/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderInterface.php
@@ -6,7 +6,7 @@
 
 use Picamator\TransferObject\DefinitionGenerator\Builder\BuilderContentInterface;
 
-interface DefinitionBuilderTraitInterface
+interface DefinitionBuilderInterface
 {
     public function createBuilderContent(string $propertyName, mixed $propertyValue): BuilderContentInterface;
 }
diff --git a/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitTest.php b/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTest.php
similarity index 72%
rename from tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitTest.php
rename to tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTest.php
index 59f9e08..cf84330 100644
--- a/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTraitTest.php
+++ b/tests/unit/DefinitionGenerator/Builder/DefinitionBuilderTest.php
@@ -8,13 +8,13 @@
 use Picamator\TransferObject\DefinitionGenerator\Builder\DefinitionBuilderTrait;
 use Picamator\TransferObject\DefinitionGenerator\Exception\DefinitionGeneratorException;
 
-class DefinitionBuilderTraitTest extends TestCase
+class DefinitionBuilderTest extends TestCase
 {
-    private DefinitionBuilderTraitInterface $builderTrait;
+    private DefinitionBuilderInterface $builder;
 
     protected function setUp(): void
     {
-        $this->builderTrait = new class () implements DefinitionBuilderTraitInterface
+        $this->builder = new class () implements DefinitionBuilderInterface
         {
             use DefinitionBuilderTrait {
                 createBuilderContent as public;
@@ -31,6 +31,6 @@ public function testUnsupportedTypeShouldThrowException(): void
         $this->expectException(DefinitionGeneratorException::class);
 
         // Act
-        $this->builderTrait->createBuilderContent($propertyName, $propertyValue);
+        $this->builder->createBuilderContent($propertyName, $propertyValue);
     }
 }
diff --git a/tests/unit/TransferGenerator/Generator/Generator/BulkTransferGeneratorTest.php b/tests/unit/TransferGenerator/Generator/Generator/ServiceTransferGeneratorTest.php
similarity index 97%
rename from tests/unit/TransferGenerator/Generator/Generator/BulkTransferGeneratorTest.php
rename to tests/unit/TransferGenerator/Generator/Generator/ServiceTransferGeneratorTest.php
index 4367f6a..4e8786e 100644
--- a/tests/unit/TransferGenerator/Generator/Generator/BulkTransferGeneratorTest.php
+++ b/tests/unit/TransferGenerator/Generator/Generator/ServiceTransferGeneratorTest.php
@@ -13,7 +13,7 @@
 use Picamator\TransferObject\TransferGenerator\Generator\Generator\TransferGeneratorServiceInterface;
 use Picamator\TransferObject\TransferGenerator\Generator\Generator\TransferGeneratorInterface;
 
-class BulkTransferGeneratorTest extends TestCase
+class ServiceTransferGeneratorTest extends TestCase
 {
     private TransferGeneratorServiceInterface $bulkGenerator;
 
diff --git a/tests/unit/TransferGenerator/Generator/Render/Template/TemplateHelperTest.php b/tests/unit/TransferGenerator/Generator/Render/Template/TemplateHelperTest.php
new file mode 100644
index 0000000..26b25e1
--- /dev/null
+++ b/tests/unit/TransferGenerator/Generator/Render/Template/TemplateHelperTest.php
@@ -0,0 +1,89 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Tests\Unit\TransferObject\TransferGenerator\Generator\Render\Template;
+
+use Generator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Picamator\TransferObject\Generated\TemplateTransfer;
+use Picamator\TransferObject\TransferGenerator\Generator\Render\Template\TemplateHelper;
+
+class TemplateHelperTest extends TestCase
+{
+    /**
+     * @param array<string,mixed> $templateData
+     */
+    #[DataProvider('getNullableDataProvider')]
+    public function testGetNullable(array $templateData, string $property, string $expected): void
+    {
+        // Arrange
+        $templateTransfer = new TemplateTransfer()->fromArray($templateData);
+        $templateHelper = new TemplateHelper($templateTransfer);
+
+        // Act
+        $actual = $templateHelper->getNullable($property);
+
+        // Assert
+        $this->assertSame($expected, $actual);
+    }
+
+    /**
+     * @return Generator<string,mixed>
+     */
+    public static function getNullableDataProvider(): Generator
+    {
+        yield 'property is not nullable should return empty string' => [
+            'templateData' => [
+                TemplateTransfer::PROPERTIES => [
+                    'test' => 'TestTransfer',
+                ],
+                TemplateTransfer::NULLABLES => [
+                    'test' => false,
+                ],
+            ],
+            'property' => 'test',
+            'expected' => '',
+        ];
+
+        yield 'property is nullable but with intersection type should return empty string' => [
+            'templateData' => [
+                TemplateTransfer::PROPERTIES => [
+                    'test' => 'TestTransfer&TTransferInterface',
+                ],
+                TemplateTransfer::NULLABLES => [
+                    'test' => true,
+                ],
+            ],
+            'property' => 'test',
+            'expected' => '',
+        ];
+
+        yield 'property is nullable with union should return union null' => [
+            'templateData' => [
+                TemplateTransfer::PROPERTIES => [
+                    'test' => 'TestTransfer|TransferInterface',
+                ],
+                TemplateTransfer::NULLABLES => [
+                    'test' => true,
+                ],
+            ],
+            'property' => 'test',
+            'expected' => 'null|',
+        ];
+
+        yield 'property is nullable without intersection or union should return null type' => [
+            'templateData' => [
+                TemplateTransfer::PROPERTIES => [
+                    'test' => 'TestTransfer',
+                ],
+                TemplateTransfer::NULLABLES => [
+                    'test' => true,
+                ],
+            ],
+            'property' => 'test',
+            'expected' => '?',
+        ];
+    }
+}
diff --git a/tests/unit/TransferGenerator/Validator/NamespaceValidatorInterface.php b/tests/unit/TransferGenerator/Validator/NamespaceValidatorInterface.php
new file mode 100644
index 0000000..a7d940d
--- /dev/null
+++ b/tests/unit/TransferGenerator/Validator/NamespaceValidatorInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Tests\Unit\TransferObject\TransferGenerator\Validator;
+
+interface NamespaceValidatorInterface
+{
+    public function isValidNamespace(?string $namespace): bool;
+}
diff --git a/tests/unit/TransferGenerator/Validator/NamespaceValidatorTest.php b/tests/unit/TransferGenerator/Validator/NamespaceValidatorTest.php
new file mode 100644
index 0000000..47f737b
--- /dev/null
+++ b/tests/unit/TransferGenerator/Validator/NamespaceValidatorTest.php
@@ -0,0 +1,57 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Picamator\Tests\Unit\TransferObject\TransferGenerator\Validator;
+
+use Generator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+use Picamator\TransferObject\TransferGenerator\Validator\NamespaceValidatorTrait;
+
+class NamespaceValidatorTest extends TestCase
+{
+    private NamespaceValidatorInterface $validator;
+
+    protected function setUp(): void
+    {
+        $this->validator = new class () implements NamespaceValidatorInterface
+        {
+            use NamespaceValidatorTrait {
+                isValidNamespace as public;
+            }
+        };
+    }
+
+    #[DataProvider('validNamespaceDataProvider')]
+    public function testValidNamespaceShouldReturnTrue(string $namespace): void
+    {
+        // Act
+        $actual = $this->validator->isValidNamespace($namespace);
+
+        // Assert
+        $this->assertTrue($actual);
+    }
+
+    /**
+     * @return Generator<string,mixed>
+     */
+    public static function validNamespaceDataProvider(): Generator
+    {
+        yield 'many sections namespace' => [
+            'Picamator\Tests\Unit\TransferObject\TransferGenerator\Validator',
+        ];
+
+        yield 'many sections namespace with first uppercase chars' => [
+            'PHPUnit\Framework\TestCase',
+        ];
+
+        yield 'two section namespace' => [
+            'Picamator\Tests',
+        ];
+
+        yield 'one section namespace' => [
+            'Picamator',
+        ];
+    }
+}