diff --git a/examples/AccountsApi/AccountsApiExample.php b/examples/AccountsApi/AccountsApiExample.php
index 282504b..03735b4 100644
--- a/examples/AccountsApi/AccountsApiExample.php
+++ b/examples/AccountsApi/AccountsApiExample.php
@@ -22,6 +22,7 @@ public function __construct()
     public function runAllExamples()
     {
         $this
+            ->createMerchant()
             ->createAccount()
             ->getAccounts()
             ->getCategories()
@@ -105,6 +106,15 @@ public function createAccount()
         return $this;
     }
 
+    public function createMerchant()
+    {
+        $merchantConfig = $this->getNewMerchantConfig();
+        $newMerchant = $this->TpayApi->accounts()->createMerchant($merchantConfig);
+        var_dump($newMerchant);
+
+        return $this;
+    }
+
     private function getNewAccountConfig()
     {
         $offerCode = 'PTON8';
@@ -148,6 +158,43 @@ private function getNewAccountConfig()
             'notifyByEmail' => true,
         ];
     }
+
+    private function getNewMerchantConfig()
+    {
+        $offerCode = 'PTON8';
+        $pos = [
+            'name' => 'Przykladowe Zakupy Online',
+            'url' => 'https://przykladowezakupy.pl',
+        ];
+        $address1 = [
+            'name' => 'Example Sp. z o.o.',
+            'street' => 'Ul. Jelenia',
+            'houseNumber' => '123',
+            'postalCode' => '54-134',
+            'city' => 'Warszawa',
+            'country' => 'PL',
+            'isInvoice' => true,
+            'isMain' => true,
+            'isCorrespondence' => true,
+        ];
+        $contactPerson = [
+            'name' => 'Jan',
+            'surname' => 'Kowalski',
+            'phone' => '(0) 111222333',
+            'email' => 'jan.kowalski@example.com',
+        ];
+
+        return [
+            'offerCode' => $offerCode,
+            'email' => 'merchant@example.com',
+            'taxId' => '7773061579',
+            'legalForm' => 3,
+            'categoryId' => 62,
+            'website' => [$pos],
+            'address' => [$address1],
+            'contactPerson' => [$contactPerson],
+        ];
+    }
 }
 
 (new AccountsApiExample())->runAllExamples();
diff --git a/src/Api/Accounts/AccountsApi.php b/src/Api/Accounts/AccountsApi.php
index 54d016e..0745ac1 100644
--- a/src/Api/Accounts/AccountsApi.php
+++ b/src/Api/Accounts/AccountsApi.php
@@ -4,6 +4,7 @@
 
 use Tpay\OpenApi\Api\ApiAction;
 use Tpay\OpenApi\Model\Objects\RequestBody\Account;
+use Tpay\OpenApi\Model\Objects\RequestBody\Merchant;
 
 class AccountsApi extends ApiAction
 {
@@ -60,12 +61,24 @@ public function getBalanceByAccountId($accountId)
         return $this->run(static::GET, sprintf('/accounts/%s/balance', $accountId));
     }
 
-    /** @param array $fields */
+    /**
+     * @deprecated Use createMerchant() instead
+     *
+     * @param array $fields
+     */
     public function createAccount($fields)
     {
+        trigger_error(sprintf('Method %s is deprecated.', __METHOD__), E_USER_DEPRECATED);
+
         return $this->run(static::POST, '/accounts', $fields, new Account());
     }
 
+    /** @param array $fields */
+    public function createMerchant($fields)
+    {
+        return $this->run(static::POST, '/v1/accounts/merchant', $fields, new Merchant());
+    }
+
     public function getMcc()
     {
         return $this->run(static::GET, '/accounts/mcc');
diff --git a/src/Factory/ArrayObjectFactory.php b/src/Factory/ArrayObjectFactory.php
new file mode 100644
index 0000000..983d97c
--- /dev/null
+++ b/src/Factory/ArrayObjectFactory.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Tpay\OpenApi\Factory;
+
+use InvalidArgumentException;
+use Tpay\OpenApi\Model\Objects\Accounts\Address as AccountAddress;
+use Tpay\OpenApi\Model\Objects\Accounts\Person;
+use Tpay\OpenApi\Model\Objects\Accounts\PointOfSale as AccountPointOfSale;
+use Tpay\OpenApi\Model\Objects\Merchant\Address as MerchantAddress;
+use Tpay\OpenApi\Model\Objects\Merchant\ContactPerson;
+use Tpay\OpenApi\Model\Objects\Merchant\PointOfSale as MerchantPointOfSale;
+use Tpay\OpenApi\Model\Objects\Objects;
+use Tpay\OpenApi\Model\Objects\RequestBody\Account;
+use Tpay\OpenApi\Model\Objects\RequestBody\Merchant;
+
+class ArrayObjectFactory
+{
+    public function create($fieldName, $parentObject)
+    {
+        if (!$parentObject instanceof Objects) {
+            throw new InvalidArgumentException(sprintf(
+                'Parent object must extend %s, got %s',
+                Objects::class,
+                is_object($parentObject) ? get_class($parentObject) : gettype($parentObject)
+            ));
+        }
+
+        if ($parentObject instanceof Merchant) {
+            switch ($fieldName) {
+                case 'address':
+                    return new MerchantAddress();
+                case 'website':
+                    return new MerchantPointOfSale();
+                case 'contactPerson':
+                    return new ContactPerson();
+                default:
+                    throw new InvalidArgumentException(sprintf('Unsupported field "%s" in %s', $fieldName, $parentObject->getName()));
+            }
+        }
+
+        if ($parentObject instanceof Account) {
+            switch ($fieldName) {
+                case 'address':
+                    return new AccountAddress();
+                case 'website':
+                    return new AccountPointOfSale();
+                case 'person':
+                    return new Person();
+                default:
+                    throw new InvalidArgumentException(sprintf('Unsupported field "%s" in %s', $fieldName, $parentObject->getName()));
+            }
+        }
+
+        throw new InvalidArgumentException(sprintf('Field %s as array is not supported in %s object', $fieldName, $parentObject->getName()));
+    }
+}
diff --git a/src/Manager/Manager.php b/src/Manager/Manager.php
index 3624987..751b551 100644
--- a/src/Manager/Manager.php
+++ b/src/Manager/Manager.php
@@ -29,6 +29,7 @@ public function setFields($fields, $strictCheck = true)
         $this->requestBody->strictCheck = $strictCheck;
         $this->requestBody->setObjectValues($this->requestBody, $fields);
         $this->ObjectsValidator->isSetRequiredFields($this->requestBody);
+        $this->ObjectsValidator->checkUniqueFields($this->requestBody);
 
         return $this;
     }
diff --git a/src/Model/Fields/Address/FlatNumber.php b/src/Model/Fields/Address/FlatNumber.php
new file mode 100644
index 0000000..934e741
--- /dev/null
+++ b/src/Model/Fields/Address/FlatNumber.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Fields\Address;
+
+use Tpay\OpenApi\Model\Fields\Field;
+
+/**
+ * @method getValue(): string
+ */
+class FlatNumber extends Field
+{
+    protected $name = __CLASS__;
+    protected $type = self::STRING;
+    protected $maxLength = 10;
+}
diff --git a/src/Model/Fields/PersonContact/Email.php b/src/Model/Fields/PersonContact/Email.php
new file mode 100644
index 0000000..8e68002
--- /dev/null
+++ b/src/Model/Fields/PersonContact/Email.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Fields\PersonContact;
+
+use Tpay\OpenApi\Model\Fields\Field;
+
+/**
+ * @method getValue(): string
+ */
+class Email extends Field
+{
+    protected $type = self::STRING;
+    protected $name = __CLASS__;
+    protected $maxLength = 255;
+}
diff --git a/src/Model/Fields/PersonContact/Phone.php b/src/Model/Fields/PersonContact/Phone.php
new file mode 100644
index 0000000..b525359
--- /dev/null
+++ b/src/Model/Fields/PersonContact/Phone.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Fields\PersonContact;
+
+use Tpay\OpenApi\Model\Fields\Field;
+
+/**
+ * @method getValue(): string
+ */
+class Phone extends Field
+{
+    protected $name = __CLASS__;
+    protected $type = self::STRING;
+    protected $maxLength = 30;
+}
diff --git a/src/Model/Objects/Accounts/Address.php b/src/Model/Objects/Accounts/Address.php
index 82606cb..d7ba354 100644
--- a/src/Model/Objects/Accounts/Address.php
+++ b/src/Model/Objects/Accounts/Address.php
@@ -23,13 +23,13 @@ class Address extends Objects
         'country' => Country::class,
         'friendlyName' => FriendlyName::class,
         'houseNumber' => HouseNumber::class,
+        'roomNumber' => RoomNumber::class,
         'isCorrespondence' => IsCorrespondence::class,
         'isInvoice' => IsInvoice::class,
         'isMain' => IsMain::class,
         'name' => Name::class,
         'phone' => Phone::class,
         'postalCode' => PostalCode::class,
-        'roomNumber' => RoomNumber::class,
         'street' => Street::class,
     ];
 
@@ -45,6 +45,9 @@ class Address extends Objects
     /** @var HouseNumber */
     public $houseNumber;
 
+    /** @var RoomNumber */
+    public $roomNumber;
+
     /** @var IsCorrespondence */
     public $isCorrespondence;
 
@@ -63,9 +66,6 @@ class Address extends Objects
     /** @var PostalCode */
     public $postalCode;
 
-    /** @var RoomNumber */
-    public $roomNumber;
-
     /** @var Street */
     public $street;
 
diff --git a/src/Model/Objects/Accounts/PointOfSale.php b/src/Model/Objects/Accounts/PointOfSale.php
index 06d95ef..0a0382f 100644
--- a/src/Model/Objects/Accounts/PointOfSale.php
+++ b/src/Model/Objects/Accounts/PointOfSale.php
@@ -35,18 +35,18 @@ class PointOfSale extends Objects
     /** @var Name */
     public $name;
 
-    /** @var PointOfSaleDate */
-    public $date;
-
-    /** @var PointOfSaleSettings */
-    public $settings;
-
     /** @var Url */
     public $url;
 
     /** @var Description */
     public $description;
 
+    /** @var PointOfSaleDate */
+    public $date;
+
+    /** @var PointOfSaleSettings */
+    public $settings;
+
     public function getRequiredFields()
     {
         return [
diff --git a/src/Model/Objects/Merchant/Address.php b/src/Model/Objects/Merchant/Address.php
new file mode 100644
index 0000000..8e920d5
--- /dev/null
+++ b/src/Model/Objects/Merchant/Address.php
@@ -0,0 +1,78 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Objects\Merchant;
+
+use Tpay\OpenApi\Model\Fields\Address\City;
+use Tpay\OpenApi\Model\Fields\Address\Country;
+use Tpay\OpenApi\Model\Fields\Address\FlatNumber;
+use Tpay\OpenApi\Model\Fields\Address\HouseNumber;
+use Tpay\OpenApi\Model\Fields\Address\IsCorrespondence;
+use Tpay\OpenApi\Model\Fields\Address\IsInvoice;
+use Tpay\OpenApi\Model\Fields\Address\IsMain;
+use Tpay\OpenApi\Model\Fields\Address\Name;
+use Tpay\OpenApi\Model\Fields\Address\Phone;
+use Tpay\OpenApi\Model\Fields\Address\PostalCode;
+use Tpay\OpenApi\Model\Fields\Address\Street;
+use Tpay\OpenApi\Model\Objects\Objects;
+
+class Address extends Objects
+{
+    const OBJECT_FIELDS = [
+        'city' => City::class,
+        'country' => Country::class,
+        'houseNumber' => HouseNumber::class,
+        'flatNumber' => FlatNumber::class,
+        'isCorrespondence' => IsCorrespondence::class,
+        'isInvoice' => IsInvoice::class,
+        'isMain' => IsMain::class,
+        'name' => Name::class,
+        'phone' => Phone::class,
+        'postalCode' => PostalCode::class,
+        'street' => Street::class,
+    ];
+
+    /** @var City */
+    public $city;
+
+    /** @var Country */
+    public $country;
+
+    /** @var HouseNumber */
+    public $houseNumber;
+
+    /** @var FlatNumber */
+    public $flatNumber;
+
+    /** @var IsCorrespondence */
+    public $isCorrespondence;
+
+    /** @var IsInvoice */
+    public $isInvoice;
+
+    /** @var IsMain */
+    public $isMain;
+
+    /** @var Name */
+    public $name;
+
+    /** @var Phone */
+    public $phone;
+
+    /** @var PostalCode */
+    public $postalCode;
+
+    /** @var Street */
+    public $street;
+
+    public function getRequiredFields()
+    {
+        return [
+            $this->name,
+            $this->street,
+            $this->houseNumber,
+            $this->postalCode,
+            $this->city,
+            $this->country,
+        ];
+    }
+}
diff --git a/src/Model/Objects/Merchant/ContactPerson.php b/src/Model/Objects/Merchant/ContactPerson.php
new file mode 100644
index 0000000..ed82296
--- /dev/null
+++ b/src/Model/Objects/Merchant/ContactPerson.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Objects\Merchant;
+
+use Tpay\OpenApi\Model\Fields\Person\Name;
+use Tpay\OpenApi\Model\Fields\Person\Surname;
+use Tpay\OpenApi\Model\Fields\PersonContact\Email;
+use Tpay\OpenApi\Model\Fields\PersonContact\Phone;
+use Tpay\OpenApi\Model\Objects\Objects;
+
+class ContactPerson extends Objects
+{
+    const OBJECT_FIELDS = [
+        'name' => Name::class,
+        'surname' => Surname::class,
+        'phone' => Phone::class,
+        'email' => Email::class,
+    ];
+
+    /** @var Name */
+    public $name;
+
+    /** @var Surname */
+    public $surname;
+
+    /** @var Phone */
+    public $phone;
+
+    /** @var Email */
+    public $email;
+}
diff --git a/src/Model/Objects/Merchant/PointOfSale.php b/src/Model/Objects/Merchant/PointOfSale.php
new file mode 100644
index 0000000..268b8e3
--- /dev/null
+++ b/src/Model/Objects/Merchant/PointOfSale.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Objects\Merchant;
+
+use Tpay\OpenApi\Model\Fields\PointOfSale\Name;
+use Tpay\OpenApi\Model\Fields\PointOfSale\Url;
+use Tpay\OpenApi\Model\Objects\Objects;
+
+class PointOfSale extends Objects
+{
+    const OBJECT_FIELDS = [
+        'name' => Name::class,
+        'url' => Url::class,
+    ];
+
+    /** @var Name */
+    public $name;
+
+    /** @var Url */
+    public $url;
+
+    public function getRequiredFields()
+    {
+        return [
+            $this->name,
+            $this->url,
+        ];
+    }
+}
diff --git a/src/Model/Objects/Objects.php b/src/Model/Objects/Objects.php
index 283c9e8..67d2464 100644
--- a/src/Model/Objects/Objects.php
+++ b/src/Model/Objects/Objects.php
@@ -4,17 +4,23 @@
 
 use InvalidArgumentException;
 use ReflectionClass;
+use Tpay\OpenApi\Factory\ArrayObjectFactory;
 use Tpay\OpenApi\Model\Fields\Field;
 
 class Objects implements ObjectsInterface
 {
     const OBJECT_FIELDS = [];
+    const UNIQUE_FIELDS = [];
 
     public $strictCheck = true;
 
+    /** @var ArrayObjectFactory */
+    private $factory;
+
     public function __construct()
     {
         $this->injectObjectFields(static::OBJECT_FIELDS);
+        $this->factory = new ArrayObjectFactory();
     }
 
     /** @return array<Field|self> */
@@ -85,6 +91,10 @@ private function setObjectsInArray($object, $fieldValue, $fieldName)
                     $this->setObjectValues($object->{$fieldName}->{$field}, $value);
                 }
                 if (is_array($object->{$fieldName})) {
+                    if (!isset($object->{$fieldName}[$field])) {
+                        $object->{$fieldName}[] = $this->factory->create($fieldName, $object);
+                    }
+
                     $this->setObjectValues($object->{$fieldName}[$field], $value);
                 }
             } else {
diff --git a/src/Model/Objects/ObjectsValidator.php b/src/Model/Objects/ObjectsValidator.php
index a689e53..e773cee 100644
--- a/src/Model/Objects/ObjectsValidator.php
+++ b/src/Model/Objects/ObjectsValidator.php
@@ -7,6 +7,18 @@
 
 class ObjectsValidator
 {
+    /** @param Objects $objectClass */
+    public function checkUniqueFields($objectClass)
+    {
+        foreach ($objectClass::UNIQUE_FIELDS as $collectionName => $fieldRules) {
+            $collection = isset($objectClass->{$collectionName}) ? $objectClass->{$collectionName} : [];
+
+            foreach ($fieldRules as $fieldName => $uniqueValue) {
+                $this->validateUniqueField($collection, $fieldName, $uniqueValue);
+            }
+        }
+    }
+
     /**
      * @param Objects $objectClass
      *
@@ -38,4 +50,41 @@ public function isSetRequiredFields($objectClass)
 
         return true;
     }
+
+    /**
+     * @param array<Objects> $objects
+     * @param mixed          $fieldName
+     * @param mixed          $uniqueValue
+     *
+     * @throws UnexpectedValueException
+     */
+    private function validateUniqueField(array $objects, $fieldName, $uniqueValue)
+    {
+        $count = 0;
+
+        foreach ($objects as $object) {
+            if (!$object instanceof Objects) {
+                continue;
+            }
+
+            if (!property_exists($object, $fieldName)) {
+                continue;
+            }
+
+            $field = $object->{$fieldName};
+
+            if ($field instanceof Field && $field->getValue() === $uniqueValue) {
+                $count++;
+            }
+
+            if ($count > 1) {
+                throw new UnexpectedValueException(sprintf(
+                    'Field "%s" with value "%s" must be unique across %s objects',
+                    $fieldName,
+                    var_export($uniqueValue, true),
+                    $object->getName()
+                ));
+            }
+        }
+    }
 }
diff --git a/src/Model/Objects/RequestBody/Merchant.php b/src/Model/Objects/RequestBody/Merchant.php
new file mode 100644
index 0000000..fdb9fc4
--- /dev/null
+++ b/src/Model/Objects/RequestBody/Merchant.php
@@ -0,0 +1,82 @@
+<?php
+
+namespace Tpay\OpenApi\Model\Objects\RequestBody;
+
+use Tpay\OpenApi\Model\Fields\Account\Krs;
+use Tpay\OpenApi\Model\Fields\Account\LegalForm;
+use Tpay\OpenApi\Model\Fields\Account\MerchantApiConsent;
+use Tpay\OpenApi\Model\Fields\Account\OfferCode;
+use Tpay\OpenApi\Model\Fields\Account\Regon;
+use Tpay\OpenApi\Model\Fields\Account\TaxId;
+use Tpay\OpenApi\Model\Fields\Person\Email;
+use Tpay\OpenApi\Model\Identifiers\CategoryId;
+use Tpay\OpenApi\Model\Objects\Merchant\Address;
+use Tpay\OpenApi\Model\Objects\Merchant\ContactPerson;
+use Tpay\OpenApi\Model\Objects\Merchant\PointOfSale;
+use Tpay\OpenApi\Model\Objects\Objects;
+
+class Merchant extends Objects
+{
+    const OBJECT_FIELDS = [
+        'offerCode' => OfferCode::class,
+        'email' => Email::class,
+        'taxId' => TaxId::class,
+        'regon' => Regon::class,
+        'krs' => Krs::class,
+        'legalForm' => LegalForm::class,
+        'categoryId' => CategoryId::class,
+        'address' => [Address::class],
+        'website' => [PointOfSale::class],
+        'contactPerson' => [ContactPerson::class],
+        'merchantApiConsent' => MerchantApiConsent::class,
+    ];
+    const UNIQUE_FIELDS = [
+        'address' => ['isMain' => true],
+    ];
+
+    /** @var OfferCode */
+    public $offerCode;
+
+    /** @var Email */
+    public $email;
+
+    /** @var TaxId */
+    public $taxId;
+
+    /** @var Regon */
+    public $regon;
+
+    /** @var Krs */
+    public $krs;
+
+    /** @var LegalForm */
+    public $legalForm;
+
+    /** @var CategoryId */
+    public $categoryId;
+
+    /** @var Address */
+    public $address;
+
+    /** @var PointOfSale */
+    public $website;
+
+    /** @var ContactPerson */
+    public $contactPerson;
+
+    /** @var MerchantApiConsent */
+    public $merchantApiConsent;
+
+    public function getRequiredFields()
+    {
+        return [
+            $this->offerCode,
+            $this->email,
+            $this->taxId,
+            $this->legalForm,
+            $this->categoryId,
+            $this->address,
+            $this->website,
+        ];
+    }
+}
diff --git a/tests/Api/Accounts/AccountsApiTest.php b/tests/Api/Accounts/AccountsApiTest.php
new file mode 100644
index 0000000..763b624
--- /dev/null
+++ b/tests/Api/Accounts/AccountsApiTest.php
@@ -0,0 +1,601 @@
+<?php
+
+namespace Api\Accounts;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+use Tpay\OpenApi\Api\Accounts\AccountsApi;
+use Tpay\OpenApi\Model\Fields\Token\AccessToken;
+use Tpay\OpenApi\Model\Objects\Authorization\Token;
+use Tpay\Tests\OpenApi\Mock\CurlMock;
+use UnexpectedValueException;
+
+class AccountsApiTest extends TestCase
+{
+    /** @dataProvider validMerchantData */
+    public function testCreatingValidMerchant(array $merchantData)
+    {
+        $transactionsApi = $this->createAccountsApiWithCurlMock('ok');
+
+        $result = $transactionsApi->createMerchant($merchantData);
+
+        self::assertSame('ok', $result);
+    }
+
+    /** @dataProvider invalidMerchantData */
+    public function testCreatingInvalidMerchant(array $merchantData, $exception, $exceptionMessage)
+    {
+        $transactionsApi = $this->createAccountsApiWithCurlMock('error');
+
+        $this->expectException($exception);
+        $this->expectExceptionMessage($exceptionMessage);
+        $transactionsApi->createMerchant($merchantData);
+    }
+
+    public function validMerchantData()
+    {
+        yield 'One Address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                        'isInvoice' => true,
+                        'isCorrespondence' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+        ];
+
+        yield 'Different Addresses' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica2',
+                        'houseNumber' => '456',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => false,
+                        'isInvoice' => true,
+                    ],
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica3',
+                        'houseNumber' => '789',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => false,
+                        'isCorrespondence' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+        ];
+
+        yield 'Many websites' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                    [
+                        'name' => 'www.example2.com',
+                        'url' => 'https://www.example2.com',
+                    ],
+                    [
+                        'name' => 'www.example3.com',
+                        'url' => 'https://www.example3.com',
+                    ],
+                ],
+            ],
+        ];
+    }
+
+    public function invalidMerchantData()
+    {
+        yield 'No Offer Code' => [
+            [
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                        'isInvoice' => true,
+                        'isCorrespondence' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Account\OfferCode" is required in object Merchant',
+        ];
+
+        yield 'No email address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Person\Email" is required in object Merchant',
+        ];
+
+        yield 'No legalForm' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Account\LegalForm" is required in object Merchant',
+        ];
+
+        yield 'No categoryId' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Identifiers\CategoryId" is required in object Merchant',
+        ];
+
+        yield 'Empty address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 0,
+                'address' => [
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\Name" is required in object Address',
+        ];
+
+        yield 'No address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 0,
+                'website' => [
+                    [
+                        'name' => 'www.example.com',
+                        'url' => 'https://www.example.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\Name" is required in object Address',
+        ];
+
+        yield 'Empty website' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 0,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\PointOfSale\Name" is required in object PointOfSale',
+        ];
+
+        yield 'No website' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@example.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 0,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'ulica1',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\PointOfSale\Name" is required in object PointOfSale',
+        ];
+
+        yield 'No street in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\Street" is required in object Address',
+        ];
+
+        yield 'No house number in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'postalCode' => '11-111',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\HouseNumber" is required in object Address',
+        ];
+
+        yield 'No postal code in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'city' => 'Poznań',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\PostalCode" is required in object Address',
+        ];
+
+        yield 'No city in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\City" is required in object Address',
+        ];
+
+        yield 'No country in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Warszawa',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "Tpay\OpenApi\Model\Fields\Address\Country" is required in object Address',
+        ];
+
+        yield 'Too long country in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Warszawa',
+                        'country' => 'Polska',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Value of field Tpay\OpenApi\Model\Fields\Address\Country is too long. Max allowed 2',
+        ];
+
+        yield 'Too short country in address' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Warszawa',
+                        'country' => 'P',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Value of field Tpay\OpenApi\Model\Fields\Address\Country is too short. Min required 2',
+        ];
+
+        yield 'Multi main addresses' => [
+            [
+                'offerCode' => 'XXXXX',
+                'email' => 'admin@exmaple.com',
+                'taxId' => '1234567890',
+                'legalForm' => 1,
+                'categoryId' => 2,
+                'address' => [
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Warszawa',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                    [
+                        'name' => 'Example Sp.z.o.o',
+                        'street' => 'glowna',
+                        'houseNumber' => '123',
+                        'postalCode' => '11-111',
+                        'city' => 'Warszawa',
+                        'country' => 'PL',
+                        'isMain' => true,
+                    ],
+                ],
+                'website' => [
+                    [
+                        'name' => 'www.example1.com',
+                        'url' => 'https://www.example1.com',
+                    ],
+                ],
+            ],
+            'exception' => UnexpectedValueException::class,
+            'exceptionMessage' => 'Field "isMain" with value "true" must be unique across Address objects',
+        ];
+    }
+
+    private function createAccountsApiWithCurlMock($response)
+    {
+        $accessToken = $this->createMock(AccessToken::class);
+
+        $token = $this->createMock(Token::class);
+        $token->access_token = $accessToken;
+
+        $transactionsApi = new AccountsApi($token, false);
+
+        CurlMock::setConsecutiveReturnedTransfers(json_encode($response));
+
+        return $transactionsApi;
+    }
+}
diff --git a/tests/Factory/ArrayObjectFactoryTest.php b/tests/Factory/ArrayObjectFactoryTest.php
new file mode 100644
index 0000000..2c958a0
--- /dev/null
+++ b/tests/Factory/ArrayObjectFactoryTest.php
@@ -0,0 +1,110 @@
+<?php
+
+namespace Factory;
+
+use InvalidArgumentException;
+use PHPUnit\Framework\TestCase;
+use stdClass;
+use Tpay\OpenApi\Factory\ArrayObjectFactory;
+use Tpay\OpenApi\Model\Objects\Accounts\Address as AccountAddress;
+use Tpay\OpenApi\Model\Objects\Accounts\Person;
+use Tpay\OpenApi\Model\Objects\Accounts\PointOfSale as AccountPointOfSale;
+use Tpay\OpenApi\Model\Objects\Merchant\Address as MerchantAddress;
+use Tpay\OpenApi\Model\Objects\Merchant\ContactPerson;
+use Tpay\OpenApi\Model\Objects\Merchant\PointOfSale as MerchantPointOfSale;
+use Tpay\OpenApi\Model\Objects\RequestBody\Account;
+use Tpay\OpenApi\Model\Objects\RequestBody\Merchant;
+use Tpay\OpenApi\Model\Objects\RequestBody\Refund;
+
+class ArrayObjectFactoryTest extends TestCase
+{
+    /** @dataProvider validObjectProvider */
+    public function testValidCreate($fieldName, $object, $expectedResult)
+    {
+        $factory = new ArrayObjectFactory();
+        $result = $factory->create($fieldName, $object);
+
+        $this->assertInstanceOf($expectedResult, $result);
+    }
+
+    /** @dataProvider invalidObjectProvider */
+    public function testInvalidCreate($fieldName, $object, $exception, $exceptionMessage)
+    {
+        $factory = new ArrayObjectFactory();
+
+        $this->expectException($exception);
+        $this->expectExceptionMessage($exceptionMessage);
+
+        $factory->create($fieldName, $object);
+    }
+
+    public function validObjectProvider()
+    {
+        yield 'merchant Address' => [
+            'fieldName' => 'address',
+            'object' => new Merchant(),
+            'expectedResult' => MerchantAddress::class,
+        ];
+
+        yield 'merchant POS' => [
+            'fieldName' => 'website',
+            'object' => new Merchant(),
+            'expectedResult' => MerchantPointOfSale::class,
+        ];
+
+        yield 'merchant contactPerson' => [
+            'fieldName' => 'contactPerson',
+            'object' => new Merchant(),
+            'expectedResult' => ContactPerson::class,
+        ];
+
+        yield 'account Address' => [
+            'fieldName' => 'address',
+            'object' => new Account(),
+            'expectedResult' => AccountAddress::class,
+        ];
+
+        yield 'account POS' => [
+            'fieldName' => 'website',
+            'object' => new Account(),
+            'expectedResult' => AccountPointOfSale::class,
+        ];
+
+        yield 'account contactPerson' => [
+            'fieldName' => 'person',
+            'object' => new Account(),
+            'expectedResult' => Person::class,
+        ];
+    }
+
+    public function invalidObjectProvider()
+    {
+        yield 'merchant non array field' => [
+            'fieldName' => 'email',
+            'object' => new Merchant(),
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Unsupported field "email" in Merchant',
+        ];
+
+        yield 'account non array field' => [
+            'fieldName' => 'taxId',
+            'object' => new Account(),
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Unsupported field "taxId" in Account',
+        ];
+
+        yield 'unsupported object' => [
+            'fieldName' => 'amount',
+            'object' => new Refund(),
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Field amount as array is not supported in Refund object',
+        ];
+
+        yield 'invalid object type' => [
+            'fieldName' => 'amount',
+            'object' => new StdClass(),
+            'exception' => InvalidArgumentException::class,
+            'exceptionMessage' => 'Parent object must extend Tpay\OpenApi\Model\Objects\Objects, got stdClass',
+        ];
+    }
+}