diff --git a/README.md b/README.md
index d009172..4bacbf6 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 
 PHP API library following Deepr specification.
 
-![](https://img.shields.io/badge/phpunit-passed-success) ![](https://img.shields.io/badge/coverage-97%25-green) ![](https://img.shields.io/github/stars/stefanak-michal/deepr-php) ![](https://img.shields.io/packagist/dt/stefanak-michal/deepr-php) ![](https://img.shields.io/github/v/release/stefanak-michal/deepr-php) ![](https://img.shields.io/github/commits-since/stefanak-michal/deepr-php/latest)
+![phpunit](https://img.shields.io/badge/phpunit-passed-success) ![coverage](https://img.shields.io/badge/coverage-94%25-green) ![stars](https://img.shields.io/github/stars/stefanak-michal/deepr-php) ![downloads](https://img.shields.io/packagist/dt/stefanak-michal/deepr-php) ![release](https://img.shields.io/github/v/release/stefanak-michal/deepr-php) ![commits](https://img.shields.io/github/commits-since/stefanak-michal/deepr-php/latest)
 
 ## Usage
 
@@ -10,7 +10,7 @@ Check [wiki](https://github.com/stefanak-michal/deepr-php/wiki) for more informa
 
 ## Requirements
 
-- PHP >= 7.1
+- PHP >= 7.2
 
 ## Installation
 
diff --git a/composer.json b/composer.json
index 4f2baff..73f1cd1 100644
--- a/composer.json
+++ b/composer.json
@@ -1,50 +1,55 @@
 {
-    "name": "stefanak-michal/deepr-php",
-    "description": "API library following Deepr specification",
-    "keywords": ["deepr", "php", "api", "rpc"],
-    "homepage": "https://github.com/stefanak-michal/deepr-php",
-    "type": "library",
-    "readme": "README.md",
-    "license": "MIT",
-    "minimum-stability": "stable",
-    "require": {
-        "php": ">=7.1.0"
-    },
-    "require-dev": {
-        "phpunit/phpunit": ">=7.5.0",
-        "ext-json": "*"
-    },
-    "support": {
-        "issues": "https://github.com/stefanak-michal/deepr-php/issues",
-        "source": "https://github.com/stefanak-michal/deepr-php"
-    },
-    "funding": [
-        {
-            "type": "paypal",
-            "url": "https://www.paypal.me/MichalStefanak"
-        }
-    ],
-    "authors": [
-        {
-            "name": "Michal Stefanak",
-            "role": "Developer",
-            "homepage": "https://www.linkedin.com/in/michalstefanak/"
-        }
-    ],
-    "autoload": {
-        "psr-4": {
-            "Deepr\\": "src/"
-        }
-    },
-    "autoload-dev": {
-        "psr-4": {
-            "Deepr\\tests\\": "tests/"
-        }
-    },
-    "scripts": {
-        "test": [
-            "Composer\\Config::disableProcessTimeout",
-            "phpunit"
-        ]
+  "name": "stefanak-michal/deepr-php",
+  "description": "API library following Deepr specification",
+  "keywords": [
+    "deepr",
+    "php",
+    "api",
+    "rpc"
+  ],
+  "homepage": "https://github.com/stefanak-michal/deepr-php",
+  "type": "library",
+  "readme": "README.md",
+  "license": "MIT",
+  "minimum-stability": "stable",
+  "require": {
+    "php": ">=7.2.0",
+    "ext-json": "*"
+  },
+  "require-dev": {
+    "phpunit/phpunit": ">=7.5.0"
+  },
+  "support": {
+    "issues": "https://github.com/stefanak-michal/deepr-php/issues",
+    "source": "https://github.com/stefanak-michal/deepr-php"
+  },
+  "funding": [
+    {
+      "type": "paypal",
+      "url": "https://www.paypal.me/MichalStefanak"
     }
+  ],
+  "authors": [
+    {
+      "name": "Michal Stefanak",
+      "role": "Developer",
+      "homepage": "https://www.linkedin.com/in/michalstefanak/"
+    }
+  ],
+  "autoload": {
+    "psr-4": {
+      "Deepr\\": "src/"
+    }
+  },
+  "autoload-dev": {
+    "psr-4": {
+      "Deepr\\tests\\": "tests/"
+    }
+  },
+  "scripts": {
+    "test": [
+      "Composer\\Config::disableProcessTimeout",
+      "phpunit"
+    ]
+  }
 }
diff --git a/src/Deepr.php b/src/Deepr.php
index b918373..9503774 100644
--- a/src/Deepr.php
+++ b/src/Deepr.php
@@ -2,14 +2,9 @@
 
 namespace Deepr;
 
-use Deepr\components\{
-    IComponent,
-    Collection,
-    ILoadable,
-    Value
-};
-use \Exception;
-use \ReflectionClass;
+use Exception;
+use Generator;
+use ReflectionClass;
 
 /**
  * Class Deepr
@@ -17,20 +12,9 @@
  * @package Deepr
  * @author Michal Stefanak
  * @link https://github.com/stefanak-michal/deepr-php
- * @link https://refactoring.guru/design-patterns/composite
  */
 final class Deepr
 {
-    /**
-     * Source Values argument key
-     * @param string
-     */
-    const OPTION_SV_KEY = 1;
-    /**
-     * Source values class names namespace prefix
-     * @param string
-     */
-    const OPTION_SV_NS = 2;
     /**
      * A context that will be passed as the last parameter to all invoked methods.
      * `null` value is ignored and it's not passed as argument
@@ -87,8 +71,6 @@ final class Deepr
      * @var array
      */
     private static $defaultOptions = [
-        self::OPTION_SV_KEY => '_type',
-        self::OPTION_SV_NS => '',
         self::OPTION_CONTEXT => null,
         self::OPTION_IGNORE_KEYS => [],
         self::OPTION_ACCEPT_KEYS => [],
@@ -102,23 +84,23 @@ final class Deepr
     private $options;
 
     /**
-     * Apply query on specific Collection instance
-     * @param Collection $root
+     * Apply query on specific object instance
+     * @param object $root
      * @param array $query
      * @param array $options
      * @return array
      * @throws Exception
      * @see setOptions()
      */
-    public function invokeQuery(Collection $root, array $query, array $options = []): array
+    public function invokeQuery(object $root, array $query, array $options = []): array
     {
         $this->setOptions($options);
 
         if (key($query) === '||')
             throw new Exception('Parallel processing not implemented');
 
-        $this->recursion($root, key($query), $query);
-        return $root->execute($this->options);
+        $output = $this->iterate($root, $query);
+        return iterator_to_array($output);
     }
 
     /**
@@ -169,153 +151,117 @@ public function setOptions(array $options = []): Deepr
     }
 
     /**
-     * Create instance of structure class by parameters
-     * @link https://github.com/deeprjs/deepr#source-values
-     * @param array $args
-     * @return IComponent
+     * Iterate through query
+     * @param mixed $root
+     * @param array $query
+     * @return Generator
      * @throws Exception
      */
-    private function getInstance(array $args): IComponent
+    public function iterate($root, array $query): Generator
     {
-        if (!array_key_exists($this->options[self::OPTION_SV_KEY], $args))
-            throw new Exception('Source values type key not found in arguments', self::ERROR_INSTANCE);
+        foreach ($query as $key => $value) {
+            $key2 = strpos($key, '=>') > 0
+                ? substr($key, 0, strpos($key, '=>'))
+                : $key;
 
-        $cls = $this->options[self::OPTION_SV_NS] . $args[$this->options[self::OPTION_SV_KEY]];
-        if (!class_exists($cls))
-            throw new Exception('Requested class "' . $cls . '" does not exists', self::ERROR_INSTANCE);
+            if ($key === '<=') {
+                $this->debug('<=');
+                if (is_object($value)) {
+                    $root = $value;
+                } else {
+                    throw new Exception('Key "<=" has to contains class instance. Are you using proper deserializer?', self::ERROR_INSTANCE);
+                }
+            } elseif ($key === '=>' && is_array($value)) {
+                $this->debug('=>');
+                yield from $this->iterate($root, $value);
+            } elseif ($value === true) {
+                $this->debug('property ' . $key);
+                if ($this->checkPropertyKey($key2)) {
+                    if (is_object($root) && property_exists($root, $key2)) {
+                        $this->authorize($root, $key2);
+                        yield $key => $root->$key2;
+                    } elseif (is_array($root) && array_key_exists($key2, $root)) {
+                        $this->authorize($root, $key2);
+                        yield $key => $root[$key2];
+                    } elseif ($key[-1] != '?') {
+                        throw new Exception('Property access is available only for class instance or array.', self::ERROR_STRUCTURE);
+                    }
+                }
+            } elseif (is_array($value) && array_key_exists('()', $value)) {
+                $this->debug('method ' . $key);
+                if (is_object($root) && method_exists($root, $key2)) {
+                    $this->authorize($root, $key2, 'call');
+                    $tmp = $value;
+                    unset($tmp['()']);
+                    $result = $this->invokeMethod($root, $key2, $value['()']);
+                    return yield $key => iterator_to_array($this->iterate($result, $tmp));
+                } elseif ($key[-1] != '?') {
+                    throw new Exception('You are trying access not existing method.', self::ERROR_MISSING);
+                }
+            } elseif (is_array($value) && is_object($root) && property_exists($root, $key2)) {
+                $this->debug('property cls ' . $key);
+                if (is_string($root->$key2) && class_exists($root->$key2))
+                    $root->$key2 = new $root->$key2();
+                yield $key => iterator_to_array($this->iterate($root->$key2, $value));
+            } elseif ($key === '[]') {
+                $this->debug('array access');
+                if (is_int($value)) {
+                    $offset = $value;
+                    $length = 1;
+                } elseif (is_array($value)) {
+                    $offset = $value[0] ?? 0;
+                    $length = $value[1] ?? null;
+                } else {
+                    throw new Exception('Wrong arguments for array access.', self::ERROR_STRUCTURE);
+                }
 
-        $reflection = new ReflectionClass($cls);
-        $invokeArgs = [];
-        if ($reflection->getConstructor()) {
-            foreach ($reflection->getConstructor()->getParameters() as $parameter) {
-                $invokeArgs[] = array_key_exists($parameter->getName(), $args)
-                    ? $args[$parameter->getName()]
-                    : $parameter->getDefaultValue();
-            }
-        }
+                $tmp = $query;
+                unset($tmp['[]']);
 
-        $instance = new $cls(...$invokeArgs);
-        if (!($instance instanceof IComponent))
-            throw new Exception($cls . ' has to implement IComponent', self::ERROR_STRUCTURE);
+                if (is_array($root))
+                    $items = array_slice($root, $offset, $length);
+                elseif (is_object($root) && is_callable($root))
+                    $items = $root($offset, $length);
+                else
+                    throw new Exception('Array access is available only for array or class implementing Arrayable interface', self::ERROR_STRUCTURE);
 
-        return $instance;
+                foreach ($items as $item) {
+                    if (is_int($value))
+                        yield from $this->iterate($item, $tmp);
+                    else
+                        yield iterator_to_array($this->iterate($item, $tmp));
+                }
+                return null;
+            } elseif (is_array($value)) {
+                $this->debug('array values');
+                yield $key => iterator_to_array($this->iterate($root, $value));
+            }
+        }
     }
 
     /**
-     * @param IComponent $root
-     * @param string $action
-     * @param array $values
+     * @param object $root
+     * @param string $method
+     * @param array $args
+     * @return mixed
      * @throws Exception
      */
-    private function recursion(IComponent &$root, string $action, array $values)
+    private function invokeMethod(object $root, string $method, array $args)
     {
-        foreach ($values as $k => $v) {
-            $key = $this->getKey($k, false);
-
-            if ($k === '<=') {
-                $this->debug('<=');
-                $tmpValues = $values;
-                unset($tmpValues['<=']);
-                $instance = $this->getInstance($v);
-                $root = $instance;
-            } elseif (is_int($k)) {
-                $this->debug('array');
-                $clone = clone $root;
-                $clone->clear();
-                $this->recursion($clone, $action, $v);
-                $root->add($clone);
-            } elseif ($k === '[]' && !empty($action)) {
-                $this->debug($action . ' []');
-                if (!($root instanceof ILoadable))
-                    throw new Exception('To access collection of class it has to implement ILoadable interface', self::ERROR_STRUCTURE);
-
-                $tmpValues = $values;
-                unset($tmpValues['[]']);
-
-                if (is_int($v)) {
-                    foreach ($root->load($v, 1)->getChildren() as $child) {
-                        $this->recursion($child, $action, $tmpValues);
-                        $root = $child;
-                    }
-                } elseif (is_array($v)) {
-                    foreach ($root->load($v[0] ?? 0, $v[1] ?? null)->getChildren() as $name => $child) {
-                        $this->recursion($child, $action, $tmpValues);
-                        $root->add($child, $name);
-                    }
-                }
-                return;
-            } elseif ($k === '()') {
-                continue;
-            } elseif (is_array($v) && array_key_exists('()', $v)) {
-                $this->debug($key . ' ()');
-                $this->authorize($key, 'call');
-
-                if (!is_null($this->options[self::OPTION_CONTEXT]))
-                    $v['()'][] = $this->options[self::OPTION_CONTEXT];
-
-                if (method_exists($root, $key)) {
-                    if (count(array_filter(array_keys($v['()']), 'is_int')) == count($v['()']))
-                        $data = $root->{$key}(...$v['()']);
-                    else {
-                        $reflection = new \ReflectionClass($root);
-                        $method = $reflection->getMethod($key);
-                        $invokeArgs = [];
-                        foreach ($method->getParameters() as $parameter) {
-                            $invokeArgs[] = array_key_exists($parameter->getName(), $v['()'])
-                                ? $v['()'][$parameter->getName()]
-                                : $parameter->getDefaultValue();
-                        }
-                        $data = $method->invokeArgs($root, $invokeArgs);
-                    }
-
-                    if (is_null($data)) {
-                        $this->recursion($root, $key, $v);
-                        $collection = new Collection();
-                        $collection->add($root, $k);
-                        $root = $collection;
-                        return;
-                    }
-
-                    if ($root === $data)
-                        $root = new Collection();
-                    if (is_subclass_of($data, Collection::class))
-                        $this->recursion($data, '', $v);
-                    elseif ($data instanceof Collection) {
-                        foreach ($data->getChildren() as $child)
-                            $this->recursion($child, '', $v);
-                    }
-                    if ($data instanceof IComponent)
-                        $root->add($data, $k);
-                    else
-                        throw new Exception('Method has to return instance of IComponent or null', self::ERROR_STRUCTURE);
-                } elseif (strpos($k, '?') === false) {
-                    throw new Exception('Missing method ' . $key, self::ERROR_MISSING);
-                }
-            } elseif ($v === true) {
-                $this->debug($action . ' ' . $k . ' true');
-                if (property_exists($root, $key)) {
-                    if ($this->checkPropertyKey($key)) {
-                        $this->authorize($key);
-                        $root->add(new Value($root->$key), $k);
-                    }
-                } elseif (strpos($k, '?') === false) {
-                    throw new Exception('Missing property ' . $key, self::ERROR_MISSING);
-                }
-            } elseif (property_exists($root, $key)) {
-                $this->debug('property ' . $key);
-                $collection = $root->$key;
-                if (is_string($collection) && class_exists($collection))
-                    $collection = new $collection();
-                if (!($collection instanceof Collection))
-                    throw new Exception('Property has to be instance of collection class or class name', self::ERROR_STRUCTURE);
-                $this->recursion($collection, $key, $v);
-                $root->add($collection, $k);
-            } elseif (is_array($v)) {
-                $this->debug($action . ' array nest');
-                $clone = clone $root;
-                $this->recursion($clone, $action, $v);
-                $root->add($clone, $k);
+        if (!is_null($this->options[self::OPTION_CONTEXT]))
+            $args[] = $this->options[self::OPTION_CONTEXT];
+
+        if (count(array_filter(array_keys($args), 'is_int')) == count($args)) {
+            return $root->{$method}(...$args);
+        } else {
+            $refMethod = (new ReflectionClass($root))->getMethod($method);
+            $invokeArgs = [];
+            foreach ($refMethod->getParameters() as $parameter) {
+                $invokeArgs[] = array_key_exists($parameter->getName(), $args)
+                    ? $args[$parameter->getName()]
+                    : $parameter->getDefaultValue();
             }
+            return $refMethod->invokeArgs($root, $invokeArgs);
         }
     }
 
@@ -340,33 +286,18 @@ private function checkPropertyKey(string $key): bool
     }
 
     /**
+     * @param array|object $root
      * @param string $key
      * @param string $operation
      * @throws Exception
      */
-    private function authorize(string $key, string $operation = 'get')
+    private function authorize($root, string $key, string $operation = 'get')
     {
-        if (is_callable($this->options[self::OPTION_AUTHORIZER]) && $this->options[self::OPTION_AUTHORIZER]($key, $operation) === false) {
+        if (is_callable($this->options[self::OPTION_AUTHORIZER]) && $this->options[self::OPTION_AUTHORIZER]($root, $key, $operation) === false) {
             throw new Exception('Operation not allowed by authorizer', self::ERROR_AUTHORIZER);
         }
     }
 
-    /**
-     * Get final key
-     * @param string $key
-     * @param bool $alias If you want the source key set this to false, otherwise will return target key
-     * @return string
-     */
-    private function getKey(string $key, bool $alias = true): string
-    {
-        $key = str_replace('?', '', $key);
-        if (strpos($key, '=>') === false)
-            return $key;
-
-        list($k, $a) = explode('=>', $key, 2);
-        return $alias ? ($a ?? $k) : $k;
-    }
-
     /**
      * @param string $msg
      */
diff --git a/src/components/Collection.php b/src/components/Collection.php
deleted file mode 100644
index 9e76206..0000000
--- a/src/components/Collection.php
+++ /dev/null
@@ -1,78 +0,0 @@
-<?php
-
-namespace Deepr\components;
-
-/**
- * Class Collection
- * @package Deepr\components
- * @author Michal Stefanak
- * @link https://github.com/stefanak-michal/deepr-php
- */
-class Collection implements IComponent
-{
-    /**
-     * @var IComponent[]
-     */
-    private $children = [];
-
-    /**
-     * Add child to collection
-     * @param IComponent $component
-     * @param string $name [Optional] To store under specific key in collection
-     */
-    final public function add(IComponent $component, string $name = '')
-    {
-        if (!empty($name))
-            $this->children[$name] = $component;
-        else
-            $this->children[] = $component;
-    }
-
-    /**
-     * Get list of children
-     * @return IComponent[]
-     */
-    final public function getChildren(): array
-    {
-        return $this->children;
-    }
-
-    /**
-     * Clear children collection
-     */
-    final public function clear()
-    {
-        $this->children = [];
-    }
-
-    /**
-     * @inheritDoc
-     */
-    final public function execute(array $options = [])
-    {
-        $output = [];
-
-        foreach ($this->getChildren() as $key => $child) {
-            $result = $child->execute($options);
-
-            if ($key !== '=>' && substr($key, -2) === '=>') { //unnest
-                $output = $result;
-            } elseif (is_array($result)) {
-                if (strpos($key, '=>') === false) { //just a key
-                    $output[$key] = $result;
-                } else {
-                    list ($k, $a) = explode('=>', $key);
-                    if (empty($k) && empty($a)) { //to return
-                        $output = array_merge($output, $result);
-                    } elseif (!empty($a)) { //nest
-                        $output = array_merge($output, [$a => $result]);
-                    }
-                }
-            } else { //value
-                $output[$key] = $result;
-            }
-        }
-
-        return $output;
-    }
-}
diff --git a/src/components/IComponent.php b/src/components/IComponent.php
deleted file mode 100644
index 66078f2..0000000
--- a/src/components/IComponent.php
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-namespace Deepr\components;
-
-/**
- * Interface IComponent
- * @package Deepr\components
- * @author Michal Stefanak
- * @link https://github.com/stefanak-michal/deepr-php
- */
-interface IComponent
-{
-    /**
-     * Execute logic on component
-     * @param array $options
-     * @return mixed
-     */
-    public function execute(array $options = []);
-}
diff --git a/src/components/ILoadable.php b/src/components/ILoadable.php
deleted file mode 100644
index 11e03b8..0000000
--- a/src/components/ILoadable.php
+++ /dev/null
@@ -1,20 +0,0 @@
-<?php
-
-namespace Deepr\components;
-
-/**
- * Interface ILoadable
- * @package Deepr\components
- * @author Michal Stefanak
- * @link https://github.com/stefanak-michal/deepr-php
- */
-interface ILoadable
-{
-    /**
-     * Get collection on "[]" call
-     * @param int $offset
-     * @param int|null $length
-     * @return Collection
-     */
-    public function load(int $offset, ?int $length): Collection;
-}
diff --git a/src/components/Value.php b/src/components/Value.php
deleted file mode 100644
index 697f415..0000000
--- a/src/components/Value.php
+++ /dev/null
@@ -1,34 +0,0 @@
-<?php
-
-namespace Deepr\components;
-
-/**
- * Class Value
- * @package Deepr\components
- * @author Michal Stefanak
- * @link https://github.com/stefanak-michal/deepr-php
- */
-class Value implements IComponent
-{
-    /**
-     * @var mixed
-     */
-    private $value;
-
-    /**
-     * Value constructor.
-     * @param mixed $value
-     */
-    public function __construct($value)
-    {
-        $this->value = $value;
-    }
-
-    /**
-     * @inheritDoc
-     */
-    final public function execute(array $options = [])
-    {
-        return $this->value;
-    }
-}
diff --git a/tests/DeeprTest.php b/tests/DeeprTest.php
index 091e596..e5d4796 100644
--- a/tests/DeeprTest.php
+++ b/tests/DeeprTest.php
@@ -4,6 +4,8 @@
 
 use Deepr\Deepr;
 use Deepr\tests\classes\Root;
+use Deepr\tests\classes\Deserializer;
+use Deepr\tests\classes\Serializer;
 use PHPUnit\Framework\TestCase;
 use Exception;
 
@@ -14,8 +16,6 @@
  * @link https://github.com/stefanak-michal/deepr-php
  *
  * @covers \Deepr\Deepr
- * @covers \Deepr\components\Collection
- * @covers \Deepr\components\Value
  */
 class DeeprTest extends TestCase
 {
@@ -29,8 +29,8 @@ public function testDeepr(): ?Deepr
 
         try {
             $deepr::$debug = true;
-            $result = $deepr->invokeQuery(new Root(), ['date' => ['()' => []]]);
-            $this->assertEquals(['date' => '2021-07-20'], $result);
+            $result = $deepr->invokeQuery(new Root(), (new Deserializer())->deserialize(['info=>' => ['()' => [], 'date=>' => true]]));
+            $this->assertEquals('2021-07-20', (new Serializer())->serialize($result));
             $deepr::$debug = false;
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
@@ -40,7 +40,7 @@ public function testDeepr(): ?Deepr
     }
 
     /**
-     * @depends testDeepr
+     * @depends      testDeepr
      * @dataProvider jsonProvider
      * @param string $input
      * @param string $output
@@ -54,14 +54,8 @@ public function testInvokeQueries(string $input, string $output, Deepr $deepr)
 
         try {
             $root = new Root();
-            $input = json_decode($input, true);
-            if (json_last_error() != JSON_ERROR_NONE)
-                throw new Exception(json_last_error_msg());
-            $result = $deepr->invokeQuery($root, $input, [
-                $deepr::OPTION_SV_NS => "\\Deepr\\tests\\classes\\"
-            ]);
-            $result = json_encode($result);
-            $this->assertJsonStringEqualsJsonString($output, $result);
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize($input));
+            $this->assertJsonStringEqualsJsonString($output, (new Serializer())->serialize($result));
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
         }
@@ -101,7 +95,7 @@ public function testParallel(Deepr $deepr)
     {
         $root = new Root();
         $this->expectException(Exception::class);
-        $deepr->invokeQuery($root, json_decode('{"||":[]}', true));
+        $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"||":[]}'));
     }
 
     /**
@@ -113,7 +107,7 @@ public function testException(Deepr $deepr)
         $root = new Root();
         $this->expectException(Exception::class);
         $this->expectExceptionCode($deepr::ERROR_STRUCTURE);
-        $deepr->invokeQuery($root, json_decode('{ "[]": [] }', true));
+        $deepr->invokeQuery($root, (new Deserializer())->deserialize('{ "[]": [] }'));
     }
 
     /**
@@ -124,10 +118,10 @@ public function testOptionIgnoreKeys(Deepr $deepr)
     {
         try {
             $root = new Root();
-            $result = $deepr->invokeQuery($root, json_decode('{"movies":{"[]":2,"_id":true,"title":true}}', true), [
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"movies":{"[]":2,"_id":true,"title":true}}'), [
                 $deepr::OPTION_IGNORE_KEYS => ['/^_/']
             ]);
-            $this->assertJsonStringEqualsJsonString(json_encode($result), '{"movies":{"title":"The Matrix Revolutions"}}');
+            $this->assertJsonStringEqualsJsonString('{"movies":{"title":"The Matrix Revolutions"}}', (new Serializer())->serialize($result));
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
         }
@@ -141,11 +135,11 @@ public function testOptionAcceptKeys(Deepr $deepr)
     {
         try {
             $root = new Root();
-            $result = $deepr->invokeQuery($root, json_decode('{"movies":{"[]":2,"_id":true,"title":true}}', true), [
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"movies":{"[]":2,"_id":true,"title":true}}'), [
                 $deepr::OPTION_IGNORE_KEYS => ['/^_/'],
                 $deepr::OPTION_ACCEPT_KEYS => ['_id']
             ]);
-            $this->assertJsonStringEqualsJsonString(json_encode($result), '{"movies":{"_id":10,"title":"The Matrix Revolutions"}}');
+            $this->assertJsonStringEqualsJsonString('{"movies":{"_id":10,"title":"The Matrix Revolutions"}}', (new Serializer())->serialize($result));
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
         }
@@ -159,10 +153,10 @@ public function testOptionContext(Deepr $deepr)
     {
         try {
             $root = new Root();
-            $result = $deepr->invokeQuery($root, json_decode('{"sayHello":{"()":["John"]}}', true), [
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"sayHello":{"()":["John"], "msg=>": true}}'), [
                 $deepr::OPTION_CONTEXT => 'Hi',
             ]);
-            $this->assertEquals(['sayHello' => 'Hi John!'], $result);
+            $this->assertJsonStringEqualsJsonString('{"sayHello": "Hi John!"}', (new Serializer())->serialize($result));
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
         }
@@ -176,12 +170,13 @@ public function testOptionAuthorizer(Deepr $deepr)
     {
         try {
             $root = new Root();
-            $result = $deepr->invokeQuery($root, json_decode('{"sayHello":{"()":["John"]}}', true), [
-                $deepr::OPTION_AUTHORIZER => function (string $key, string $operation) {
-                    return $key == 'sayHello' && $operation == 'call';
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"sayHello":{"()":["John"], "msg=>": true}}'), [
+                $deepr::OPTION_AUTHORIZER => function ($root, string $key, string $operation) {
+                    return ($root instanceof Root && $key == 'sayHello' && $operation == 'call')
+                        || (is_array($root) && $key == 'msg' && $operation == 'get');
                 }
             ]);
-            $this->assertEquals(['sayHello' => 'Hello John!'], $result);
+            $this->assertJsonStringEqualsJsonString('{"sayHello": "Hello John!"}', (new Serializer())->serialize($result));
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
         }
@@ -196,8 +191,8 @@ public function testOptionAuthorizerException(Deepr $deepr)
         $root = new Root();
         $this->expectException(Exception::class);
         $this->expectExceptionCode($deepr::ERROR_AUTHORIZER);
-        $deepr->invokeQuery($root, json_decode('{"sayHello":{"()":["John"]}}', true), [
-            $deepr::OPTION_AUTHORIZER => function (string $key, string $operation) {
+        $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"sayHello":{"()":["John"]}}'), [
+            $deepr::OPTION_AUTHORIZER => function ($root, string $key, string $operation) {
                 return false;
             }
         ]);
@@ -211,8 +206,11 @@ public function testSetOptions(Deepr $deepr)
     {
         try {
             $deepr->setOptions([
-                $deepr::OPTION_SV_KEY => null,
-                $deepr::OPTION_IGNORE_KEYS => null
+                $deepr::OPTION_CONTEXT => 'abc',
+                $deepr::OPTION_IGNORE_KEYS => null,
+                $deepr::OPTION_ACCEPT_KEYS => ['/.*/'],
+                $deepr::OPTION_AUTHORIZER => function ($root, string $key, string $operation) {
+                }
             ]);
             $this->assertInstanceOf(Deepr::class, $deepr);
         } catch (Exception $e) {
@@ -229,7 +227,7 @@ public function testSetOptionsStringException(Deepr $deepr)
         $this->expectException(Exception::class);
         $this->expectExceptionCode($deepr::ERROR_OPTIONS);
         $deepr->setOptions([
-            $deepr::OPTION_SV_KEY => ['this has to be string and not a array'],
+            $deepr::OPTION_ACCEPT_KEYS => 'this has to be array and not a string',
         ]);
     }
 
@@ -267,7 +265,7 @@ public function testFaultTolerant(Deepr $deepr)
     {
         try {
             $root = new Root();
-            $result = $deepr->invokeQuery($root, json_decode('{"abc?": true, "method?": {"()": []}}', true));
+            $result = $deepr->invokeQuery($root, (new Deserializer())->deserialize('{"abc?": true, "method?": {"()": []}}'));
             $this->assertEquals([], $result);
         } catch (Exception $e) {
             $this->markTestIncomplete($e->getMessage());
diff --git a/tests/classes/Deserializer.php b/tests/classes/Deserializer.php
new file mode 100644
index 0000000..afea750
--- /dev/null
+++ b/tests/classes/Deserializer.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace Deepr\tests\classes;
+
+use Exception;
+
+/**
+ * Class Deserializer
+ * @package Deepr\tests\classes
+ * @author Michal Stefanak
+ * @link https://github.com/stefanak-michal/deepr-php
+ */
+class Deserializer
+{
+    /**
+     * @param string|array $query
+     * @return array
+     * @throws Exception
+     */
+    public function deserialize($query): array
+    {
+        if (is_string($query)) {
+            $query = json_decode($query, true);
+            if (json_last_error() != JSON_ERROR_NONE)
+                throw new Exception(json_last_error_msg());
+        } elseif (!is_array($query)) {
+            throw new Exception('Deserialization expects JSON string or array');
+        }
+
+        return $this->recursion($query);
+    }
+
+    /**
+     * @param array $query
+     * @return array
+     * @throws Exception
+     */
+    private function recursion(array $query): array
+    {
+        foreach ($query as $key => &$value) {
+            if ($key === '<=') { // insert class instance by query
+                if (array_key_exists('_type', $value) && class_exists("\\Deepr\\tests\\classes\\" . $value['_type'])) {
+                    $clsName = "\\Deepr\\tests\\classes\\" . $value['_type'];
+                    unset($value['_type']);
+                    $value = new $clsName(...array_values($value));
+                }
+            }
+
+            if (is_array($value)) {
+                $value = $this->deserialize($value);
+            }
+        }
+
+        return $query;
+    }
+}
diff --git a/tests/classes/Movie.php b/tests/classes/Movie.php
index bd6aa2c..e6e6037 100644
--- a/tests/classes/Movie.php
+++ b/tests/classes/Movie.php
@@ -2,16 +2,13 @@
 
 namespace Deepr\tests\classes;
 
-use Deepr\components\Collection;
-use Deepr\components\IComponent;
-
 /**
  * Class Movie
  * @package Deepr\tests\classes
  * @author Michal Stefanak
  * @link https://github.com/stefanak-michal/deepr-php
  */
-class Movie extends Collection
+class Movie
 {
     public $_id;
     /**
@@ -24,30 +21,34 @@ class Movie extends Collection
      * @var int
      */
     public $released;
+    /**
+     * {"movies": {"[]":[], "tagline": true}}
+     * @var string
+     */
     public $tagline;
 
     /**
-     * @var Collection
+     * @var array
      */
     private $actors;
 
     /**
      * RPC method to get actors of movie
      * {"movies":{"[]":[],"=>":{"getActors":{"()":[]}}}}
-     * @return IComponent
+     * @return array
      * @see \Deepr\tests\classes\Person
      */
-    public function getActors(): IComponent
+    public function getActors(): array
     {
         if (is_null($this->actors)) {
-            $this->actors = new Collection();
+            $this->actors = [];
             foreach (Database::getMovieActors($this->_id) as $row) {
                 $person = new Person();
                 $person->_id = $row['_id'];
                 $person->name = $row['name'];
                 $person->born = $row['born'];
                 $person->_movies = $row['_movies'];
-                $this->actors->add($person);
+                $this->actors[] = $person;
             }
         }
 
@@ -55,9 +56,10 @@ public function getActors(): IComponent
     }
 
     /**
-     * RPC method to get movie by title. Use it with source values call.
+     * RPC method to get movie by title.
      * {"<=": {"_type": "Movie"}, "byTitle": {"()": ["The Matrix"]}}
      * @param string $title
+     * @return Movie
      * @see \Deepr\tests\classes\Movie
      */
     public function byTitle(string $title)
@@ -69,6 +71,7 @@ public function byTitle(string $title)
             $this->released = $row['released'];
             $this->tagline = $row['tagline'];
         }
+        return $this;
     }
 
 }
diff --git a/tests/classes/Movies.php b/tests/classes/Movies.php
index 57e88c4..8f80f78 100644
--- a/tests/classes/Movies.php
+++ b/tests/classes/Movies.php
@@ -2,10 +2,6 @@
 
 namespace Deepr\tests\classes;
 
-use Deepr\components\Collection;
-use Deepr\components\IComponent;
-use Deepr\components\ILoadable;
-
 /**
  * Class Movies
  * Interface ILoadable is required if you want to access collection items with "[]"
@@ -13,7 +9,7 @@
  * @author Michal Stefanak
  * @link https://github.com/stefanak-michal/deepr-php
  */
-class Movies extends Collection implements ILoadable
+class Movies
 {
     /**
      * {"movies": {"count": true}}
@@ -27,24 +23,40 @@ public function __construct()
     }
 
     /**
-     * This method is implemented by interface ILoadable and it's called on "[]"
-     * {"movies": {"[]": []}}
+     * RPC method to get movie by title
+     * {"movies": {"getByTitle": {"()": ["The Matrix"]}}}
+     * @param string $title
+     * @return Movie
+     */
+    public function getByTitle(string $title): Movie
+    {
+        $row = Database::getMovieByTitle($title);
+        $movie = new Movie();
+        $movie->_id = $row['_id'];
+        $movie->title = $row['title'];
+        $movie->released = $row['released'];
+        $movie->tagline = $row['tagline'];
+        return $movie;
+    }
+
+    /**
+     * This magic method is called on "[]" array access
      * @param int $offset
      * @param int|null $length
-     * @return Collection
-     * @see \Deepr\tests\classes\Movie
+     * @return array
      */
-    public function load(int $offset, ?int $length): Collection
+    public function __invoke(int $offset, ?int $length): array
     {
-        $items = new Collection();
+        $output = [];
         foreach (array_slice(Database::getMovies(), $offset, $length) as $row) {
             $movie = new Movie();
             $movie->_id = $row['_id'];
             $movie->title = $row['title'];
             $movie->released = $row['released'];
             $movie->tagline = $row['tagline'];
-            $items->add($movie);
+            $output[] = $movie;
         }
-        return $items;
+        return $output;
     }
+
 }
diff --git a/tests/classes/Person.php b/tests/classes/Person.php
index 7050712..1459ee0 100644
--- a/tests/classes/Person.php
+++ b/tests/classes/Person.php
@@ -2,15 +2,13 @@
 
 namespace Deepr\tests\classes;
 
-use Deepr\components\Collection;
-
 /**
  * Class Person
  * @package Deepr\tests\classes
  * @author Michal Stefanak
  * @link https://github.com/stefanak-michal/deepr-php
  */
-class Person extends Collection
+class Person
 {
     public $_id;
     /**
@@ -18,8 +16,15 @@ class Person extends Collection
      * @var string
      */
     public $name;
+    /**
+     * @var int
+     */
     public $born;
 
+    /**
+     * IDs of movies
+     * @var array
+     */
     public $_movies;
 
     /**
@@ -43,11 +48,11 @@ public function __construct(int $id = -1)
     /**
      * RPC method to get movies in which actor acted
      * {..actor: {"getMovies":{"()": []}}
-     * @return Collection
+     * @return array
      */
-    public function getMovies(): Collection
+    public function getMovies(): array
     {
-        $items = new Collection();
+        $items = [];
         if (empty($this->_movies))
             return $items;
         foreach (Database::getMovies() as $row) {
@@ -57,7 +62,7 @@ public function getMovies(): Collection
                 $movie->title = $row['title'];
                 $movie->released = $row['released'];
                 $movie->tagline = $row['tagline'];
-                $items->add($movie);
+                $items[] = $movie;
             }
         }
         return $items;
diff --git a/tests/classes/Root.php b/tests/classes/Root.php
index 6df873a..2947899 100644
--- a/tests/classes/Root.php
+++ b/tests/classes/Root.php
@@ -2,8 +2,6 @@
 
 namespace Deepr\tests\classes;
 
-use Deepr\components\{Collection, Value, IComponent};
-
 /**
  * Class Root
  * This object is provided for Deepr->invokeQuery
@@ -11,14 +9,14 @@
  * @author Michal Stefanak
  * @link https://github.com/stefanak-michal/deepr-php
  */
-class Root extends Collection
+class Root
 {
     /**
      * Reference to Movies collection
      * Only public properties are accessible
-     * {"movies": ...}
+     * {"movies": {...}}
      * @internal It can be instance of class Movies directly
-     * @var string|Collection
+     * @var string|Movies
      * @see \Deepr\tests\classes\Movies
      */
     public $movies = Movies::class;
@@ -26,21 +24,24 @@ class Root extends Collection
     /**
      * Sample method
      * RPC methods has to be public and returns IComponent
-     * {"date": {"()": []}}
-     * @return IComponent
+     * {"info": {"()": [], "date": true}}
+     * @see \Deepr\tests\DeeprTest::testDeepr()
+     * @return array
      */
-    public function date(): IComponent
+    public function info(): array
     {
-        return new Value('2021-07-20');
+        return ['date' => '2021-07-20'];
     }
 
     /**
+     * For testing OPTION_CONTEXT
+     * @see \Deepr\tests\DeeprTest::testOptionContext()
      * @param string $value
      * @param string $prefix
-     * @return IComponent
+     * @return array
      */
-    public function sayHello(string $value, string $prefix = 'Hello'): IComponent
+    public function sayHello(string $value, string $prefix = 'Hello'): array
     {
-        return new Value($prefix . ' ' . $value . '!');
+        return ['msg' => $prefix . ' ' . $value . '!'];
     }
 }
diff --git a/tests/classes/Serializer.php b/tests/classes/Serializer.php
new file mode 100644
index 0000000..80079d8
--- /dev/null
+++ b/tests/classes/Serializer.php
@@ -0,0 +1,55 @@
+<?php
+
+namespace Deepr\tests\classes;
+
+use Exception;
+
+/**
+ * Class Serializer
+ * @package Deepr\tests\classes
+ * @author Michal Stefanak
+ * @link https://github.com/stefanak-michal/deepr-php
+ */
+class Serializer
+{
+
+    /**
+     * Serialize into formatted JSON
+     * @param array $result
+     * @return string
+     * @throws Exception
+     */
+    public function serialize(array $result): string
+    {
+        $output = $this->recursion($result);
+        if (!is_string($output)) {
+            $output = json_encode($output, JSON_PRETTY_PRINT);
+            if (json_last_error() != JSON_ERROR_NONE)
+                throw new Exception(json_last_error_msg());
+        }
+        return $output;
+    }
+
+    /**
+     * @param array $result
+     * @return mixed
+     */
+    private function recursion(array $result)
+    {
+        $output = [];
+        foreach ($result as $key => $value) {
+            if (is_array($value))
+                $value = $this->recursion($value);
+
+            if ($key !== '=>' && substr($key, -2) === '=>') { //unnest
+                return $value;
+            } else { //value
+                $a = $key;
+                if (strpos($key, '=>') !== false)
+                    list ($k, $a) = explode('=>', $key);
+                $output[$a] = $value;
+            }
+        }
+        return $output;
+    }
+}
diff --git a/tests/jsons/07-input.json b/tests/jsons/07-input.json
index aa7d43f..c6ca86e 100644
--- a/tests/jsons/07-input.json
+++ b/tests/jsons/07-input.json
@@ -5,6 +5,7 @@
       "title": true,
       "getActors=>actors": {
         "()": [],
+        "[]": [],
         "name": true
       }
     }
diff --git a/tests/jsons/09-input.json b/tests/jsons/09-input.json
index b47f57c..fb035b2 100644
--- a/tests/jsons/09-input.json
+++ b/tests/jsons/09-input.json
@@ -1,5 +1,6 @@
 {
-  "date": {
-    "()": []
+  "info": {
+    "()": [],
+    "date": true
   }
 }
\ No newline at end of file
diff --git a/tests/jsons/09-output.json b/tests/jsons/09-output.json
index 882b8b0..053e475 100644
--- a/tests/jsons/09-output.json
+++ b/tests/jsons/09-output.json
@@ -1,3 +1,5 @@
 {
-  "date": "2021-07-20"
+  "info": {
+    "date": "2021-07-20"
+  }
 }
\ No newline at end of file
diff --git a/tests/jsons/12-input.json b/tests/jsons/12-input.json
index dbaedf0..a20f98e 100644
--- a/tests/jsons/12-input.json
+++ b/tests/jsons/12-input.json
@@ -5,9 +5,11 @@
       "title": true,
       "getActors=>actors": {
         "()": [],
+        "[]": [],
         "name": true,
         "getMovies=>movies": {
           "()": [],
+          "[]": [],
           "title=>": true
         }
       }
diff --git a/tests/jsons/13-input.json b/tests/jsons/13-input.json
index bf9faa6..8a32944 100644
--- a/tests/jsons/13-input.json
+++ b/tests/jsons/13-input.json
@@ -7,6 +7,7 @@
     "name": true,
     "getMovies": {
       "()": [],
+      "[]": [],
       "title": true
     }
   }