diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
new file mode 100644
index 0000000..3793d13
--- /dev/null
+++ b/.github/workflows/phpstan.yml
@@ -0,0 +1,29 @@
+name: PHPStan
+
+on:
+  pull_request:
+    paths:
+      - "**.php"
+      - "phpstan.neon.dist"
+  push:
+    branches:
+      - main
+
+jobs:
+  phpstan:
+    name: phpstan
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: "8.2"
+          coverage: none
+
+      - name: Install composer dependencies
+        uses: ramsey/composer-install@v3
+
+      - name: Run PHPStan
+        run: ./vendor/bin/phpstan analyse --error-format=github --debug
diff --git a/.gitignore b/.gitignore
index 841e6e5..674fc48 100644
--- a/.gitignore
+++ b/.gitignore
@@ -10,4 +10,4 @@ phpunit.xml
 psalm.xml
 vendor
 .php-cs-fixer.cache
-
+!docs
\ No newline at end of file
diff --git a/README.md b/README.md
index 1050307..393a76a 100644
--- a/README.md
+++ b/README.md
@@ -1,13 +1,12 @@
-
 # KvK API client (Dutch Chamber of Commerce)
 
 [![Latest Version on Packagist](https://img.shields.io/packagist/v/vormkracht10/kvk-api.svg?style=flat-square)](https://packagist.org/packages/vormkracht10/kvk-api)
 [![Tests](https://github.com/vormkracht10/kvk-api/actions/workflows/run-tests.yml/badge.svg?branch=main)](https://github.com/vormkracht10/kvk-api/actions/workflows/run-tests.yml)
 [![Total Downloads](https://img.shields.io/packagist/dt/vormkracht10/kvk-api.svg?style=flat-square)](https://packagist.org/packages/vormkracht10/kvk-api)
 
-PHP package to communicate with the business register of the Dutch Chamber of Commerce. 
+PHP package to communicate with the business register of the Dutch Chamber of Commerce.
 
-At the moment it is only possible to search by company name. The result will contain the following data: 
+At the moment it is only possible to search by company name. The result will contain the following data:
 
 <ul>
   <li>KvK number</li>
@@ -25,12 +24,19 @@ You can install the package via composer:
 composer require vormkracht10/kvk-api
 ```
 
+## Upgrade guide
+
+See the [upgrade guide](docs/upgrade.md) for more information on what has changed recently.
+
 ## Usage
 
+> Note: if you don't have an API key yet, get yours at the [developer portal](https://developers.kvk.nl/) of the Chamber of Commerce
+
 ```php
 use Vormkracht10\KvkApi\ClientFactory;
-
 $apiKey = '<KVK_API_KEY>';
+
+// Optional SSL certificate
 $rootCertificate = '<PATH_TO_SSL_CERT>';
 
 $kvk = ClientFactory::create($apiKey, $rootCertificate);
@@ -38,8 +44,34 @@ $kvk = ClientFactory::create($apiKey, $rootCertificate);
 // Search by company name
 $companies = $kvk->search('Vormkracht10');
 ```
-> Note: if you don't have an API key yet, get yours at the [developer portal](https://developers.kvk.nl/) of the Chamber of Commerce
 
+### Search with additional parameters
+
+```php
+$companies = $kvk->search('Vormkracht10', [
+'pagina' => 1,
+'resultatenPerPagina' => 10
+]);
+```
+
+### Set page and results per page before searching
+
+```php
+$kvk->setPage(2);
+$kvk->setResultsPerPage(20);
+```
+
+### Search by KvK number
+
+```php
+$companies = $kvk->searchByKvkNumber('12345678');
+```
+
+### Search by RSIN
+
+```php
+$companies = $kvk->searchByRSIN('12345678');
+```
 
 ## Testing
 
@@ -53,8 +85,8 @@ Please see [CHANGELOG](CHANGELOG.md) for more information on what has changed re
 
 ## Credits
 
-- [Bas van Dinther](https://github.com/Baspa)
-- [All Contributors](../../contributors)
+-   [Bas van Dinther](https://github.com/Baspa)
+-   [All Contributors](../../contributors)
 
 ## License
 
diff --git a/composer.json b/composer.json
index c601b99..b139406 100644
--- a/composer.json
+++ b/composer.json
@@ -15,13 +15,14 @@
         }
     ],
     "require": {
-        "php": "^7.4|^8.0",
+        "php": "^7.4|^8.0|^8.1|^8.2|^8.3",
         "guzzlehttp/guzzle": "^7.0",
-        "illuminate/support": "^8.0|^9.0|^10.0"
+        "illuminate/support": "^8.0|^9.0|^10.0|^11.0"
     },
     "require-dev": {
         "friendsofphp/php-cs-fixer": "^3.0",
         "pestphp/pest": "^1.20",
+        "phpstan/phpstan": "^1.12",
         "spatie/ray": "^1.28"
     },
     "autoload": {
diff --git a/docs/upgrade.md b/docs/upgrade.md
new file mode 100644
index 0000000..5c8ce49
--- /dev/null
+++ b/docs/upgrade.md
@@ -0,0 +1,62 @@
+# Upgrading from v1.x to v2.x
+
+## Changes in Search Results
+
+In the new version, the search results have been expanded to include more detailed information. The Company object now contains the following data:
+
+-   KvK number
+-   Establishment number
+-   Tradename
+-   Address(es) (including type, full address, street, house number, zip code, city, and country)
+-   Website(s)
+
+## New Search Methods
+
+1. Search by KvK Number
+   The new version introduces the ability to search by KvK number:
+
+```php
+$companies = $kvk->searchByKvkNumber('12345678');
+```
+
+2. Search by RSIN
+   You can now search by RSIN (Rechtspersonen en Samenwerkingsverbanden Informatienummer):
+
+```php
+$companies = $kvk->searchByRSIN('12345678');
+```
+
+## Pagination Support
+
+The new version adds support for pagination in search results:
+
+```php
+$kvk->setPage(2);
+$kvk->setResultsPerPage(20);
+```
+
+Alternatively, you can pass these parameters directly to the search method:
+
+```php
+$companies = $kvk->search('Vormkracht10', [
+    'pagina' => 1,
+    'resultatenPerPagina' => 10
+]);
+```
+
+## Updating dependencies
+
+```bash
+{
+    "require": {
+        "vormkracht10/kvk-api": "^2.0"
+    }
+}
+```
+
+Then run `composer update` to install the new version.
+
+## Breaking changes
+
+-   The structure of the Company object has changed. Make sure to update any code that relies on the specific structure of the search results.
+-   The method signatures for creating the client and performing searches have been updated. Review and update your code accordingly.
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..9250404
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,7 @@
+parameters:
+    level: 8
+    paths:
+        - src
+    tmpDir: build/phpstan
+    parallel:
+        maximumNumberOfProcesses: 1
\ No newline at end of file
diff --git a/src/Client.php b/src/Client.php
index cfef1c1..46066b4 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -2,102 +2,173 @@
 
 namespace Vormkracht10\KvKApi;
 
+use GuzzleHttp\ClientInterface;
 use Illuminate\Support\Collection;
+use Psr\Http\Message\ResponseInterface;
+use stdClass;
 use Vormkracht10\KvKApi\Company\Company;
 
 class Client
 {
-    private $httpClient;
-    private $baseUrl;
-    private array $results;
-
-    public function __construct($httpClient)
+    private ClientInterface $httpClient;
+    private string $baseUrl;
+    /** @var array<Company> */
+    private array $results = [];
+    private int $page = 1;
+    private int $resultsPerPage = 10;
+
+    public function __construct(ClientInterface $httpClient)
     {
         $this->httpClient = $httpClient;
-        $this->baseUrl = 'https://api.kvk.nl/api/v1/';
+        $this->baseUrl = 'https://api.kvk.nl/api/v2/';
     }
 
-    public function getData(string $search)
+    /**
+     * @param array<string, mixed> $params
+     * @return array<Company>
+     */
+    public function search(string $search, array $params = []): array
     {
-        $url = $this->baseUrl . 'zoeken?handelsnaam=' . $search;
+        $queryParams = array_merge([
+            'naam' => $search,
+            'pagina' => $this->page,
+            'resultatenPerPagina' => $this->resultsPerPage,
+        ], $params);
+        $data = $this->getData($queryParams);
+
+        $parsedData = $this->parseData($this->decodeJson($data));
 
-        $response = $this->httpClient->get($url);
+        foreach ($parsedData as $item) {
+            $data = $this->decodeJson($this->getRelatedData($item));
+
+            $this->results[] = new Company(
+                $data->kvkNummer ?? '',
+                $data->vestigingsnummer ?? null,
+                $data->naam ?? null,
+                $data->adres ?? null,
+                $data->websites ?? null
+            );
+        };
+
+        return $this->results;
+    }
+
+    /**
+     * @param array<string, mixed> $params
+     */
+    private function getData(array $params): string
+    {
+        $url = $this->baseUrl . 'zoeken?' . http_build_query($params);
+
+        $response = $this->httpClient->request('GET', $url);
 
         return $this->getJson($response);
     }
 
-    private function getJson(object $response)
+    private function getJson(ResponseInterface $response): string
     {
-        return $response->getBody()->getContents();
+        return (string) $response->getBody()->getContents();
     }
 
-    private function decodeJson(string $json)
+    /**
+     * @return stdClass
+     */
+    private function decodeJson(string $json): stdClass
     {
-        return json_decode($json);
+        return json_decode($json, false) ?: new stdClass();
     }
 
-    public function search(string $search)
+    public function setPage(int $page): self
     {
-        $data = $this->getData($search);
+        $this->page = $page;
 
-        $parsedData = $this->parseData($this->decodeJson($data));
+        return $this;
+    }
 
-        $parsedData->data->each(function ($item) {
-            $data = json_decode($this->getRelatedData($item));
+    public function setResultsPerPage(int $resultsPerPage): self
+    {
+        $this->resultsPerPage = $resultsPerPage;
 
-            $this->results[] = new Company(
-                $data->kvkNummer ?? null,
-                $data->vestigingsnummer ?? null,
-                $data->eersteHandelsnaam ?? null,
-                $data->adressen ?? null,
-                $data->websites ?? null
-            );
-        });
+        return $this;
+    }
 
-        return $this->results;
+    /**
+     * @param array<string, mixed> $params
+     * @return array<Company>
+     */
+    public function searchByKvkNumber(string $kvkNumber, array $params = []): array
+    {
+        return $this->search('', array_merge(['kvkNummer' => $kvkNumber], $params));
     }
 
-    private function parseData(object $data)
+    /**
+     * @param array<string, mixed> $params
+     * @return array<Company>
+     */
+    public function searchByRsin(string $rsin, array $params = []): array
     {
-        $data = collect($data->resultaten);
+        return $this->search('', array_merge(['rsin' => $rsin], $params));
+    }
 
-        $data = $data->map(function ($value, $key) {
-            $value->attributes = collect($value)->except(['type', 'links']);
+    /**
+     * @param array<string, mixed> $params
+     * @return array<Company>
+     */
+    public function searchByVestigingsnummer(string $vestigingsnummer, array $params = []): array
+    {
+        return $this->search('', array_merge(['vestigingsnummer' => $vestigingsnummer], $params));
+    }
 
+    /**
+     * @return array<int, stdClass>
+     */
+    private function parseData(stdClass $data): array
+    {
+        $resultaten = $data->resultaten ?? [];
+        /** @var array<int, stdClass> $resultatenArray */
+        $resultatenArray = is_array($resultaten) ? $resultaten : [];
+
+        return array_map(function ($value) {
+            $value = (object) $value;
+            /** @var array<string, mixed> $attributes */
+            $attributes = array_diff_key((array) $value, array_flip(['type', 'links']));
+            $value->attributes = $attributes;
             $value->id = uniqid();
 
-            $value = collect($value)->except($value->attributes->keys());
-
-            $links = collect($value['links']);
-
-            $links = $links->mapWithKeys(function ($value, $key) {
-                return [$value->rel => $value->href];
-            });
-
-            $value['links'] = $links;
+            if (isset($value->links)) {
+                /** @var array<stdClass> $links */
+                $links = $value->links;
+                /** @var array<string, string> $mappedLinks */
+                $mappedLinks = array_column($links, 'href', 'rel');
+                $value->links = $mappedLinks;
+            } else {
+                /** @var array<string, string> $emptyLinks */
+                $emptyLinks = [];
+                $value->links = $emptyLinks;
+            }
+
+            $value->actief = $value->actief ?? null;
+            $value->vervallenNaam = $value->vervallenNaam ?? null;
 
             return $value;
-        });
-
-        $object = new \stdClass();
-
-        $object->data = $data;
-
-        return $object;
+        }, $resultatenArray);
     }
 
-    private function getRelatedData($parsedData): Collection
+    private function getRelatedData(stdClass $parsedData): string
     {
-        $relatedData = collect();
+        $relatedData = [];
+
+        /** @var Collection<string, string> $links */
+        $links = collect((array)($parsedData->links ?? []));
 
-        collect($parsedData['links'])->each(function ($link, $key) use (&$relatedData) {
-            $response = $this->httpClient->get($link);
+        $links->each(function (string $link) use (&$relatedData) {
+            $response = $this->httpClient->request('GET', $link);
 
             $data = $this->decodeJson($this->getJson($response));
 
-            $relatedData = $relatedData->merge($data);
+            $relatedData = array_merge($relatedData, (array) $data);
         });
 
-        return $relatedData;
+        return json_encode($relatedData) ?: '{}';
     }
 }
diff --git a/src/ClientFactory.php b/src/ClientFactory.php
index 41e78e7..a6fcc5c 100644
--- a/src/ClientFactory.php
+++ b/src/ClientFactory.php
@@ -7,7 +7,7 @@
 
 class ClientFactory
 {
-    public static function create(string $apiKey, string $rootCertificate): KvKApiClient
+    public static function create(string $apiKey, ?string $rootCertificate = null): KvKApiClient
     {
         return new KvKApiClient(
             self::createHttpClient($apiKey, $rootCertificate)
@@ -16,15 +16,21 @@ public static function create(string $apiKey, string $rootCertificate): KvKApiCl
 
     private static function createHttpClient(
         string $apiKey,
-        string $rootCertificate
-    ) {
-        $client = new Client([
+        ?string $rootCertificate = null
+    ): Client {
+        if ($rootCertificate === null) {
+            return new Client([
+                'headers' => [
+                    'apikey' => $apiKey,
+                ],
+            ]);
+        }
+
+        return new Client([
             'headers' => [
                 'apikey' => $apiKey,
             ],
             'verify' => $rootCertificate,
         ]);
-
-        return $client;
     }
 }
diff --git a/src/Company/Address.php b/src/Company/Address.php
index 808e4d3..1b563a5 100644
--- a/src/Company/Address.php
+++ b/src/Company/Address.php
@@ -4,6 +4,13 @@
 
 class Address
 {
+    private string $type;
+    private ?string $street;
+    private ?int $houseNumber;
+    private string $postalCode;
+    private string $city;
+    private string $country;
+
     public function __construct(
         string $type,
         ?string $street,
@@ -50,6 +57,9 @@ public function getCountry(): string
         return $this->country;
     }
 
+    /**
+     * @return array<string, string|int|null>
+     */
     public function get(): array
     {
         return [
diff --git a/src/Company/Company.php b/src/Company/Company.php
index 6497958..1212b72 100644
--- a/src/Company/Company.php
+++ b/src/Company/Company.php
@@ -4,16 +4,18 @@
 
 class Company
 {
-    private $kvkNumber;
-
-    private $establishmentNumber;
-
-    private $tradeName;
-
-    private $addresses;
-
-    private $websites;
+    private string $kvkNumber;
+    private ?string $establishmentNumber;
+    private ?string $tradeName;
+    /** @var array<mixed>|null */
+    private ?array $addresses;
+    /** @var array<string>|null */
+    private ?array $websites;
 
+    /**
+     * @param array<mixed>|null $addresses
+     * @param array<string>|null $websites
+     */
     public function __construct(
         string $kvkNumber,
         ?string $establishmentNumber,
@@ -33,7 +35,7 @@ public function getKvkNumber(): string
         return $this->kvkNumber;
     }
 
-    public function getEstablishmentNumber(): string
+    public function getEstablishmentNumber(): ?string
     {
         return $this->establishmentNumber;
     }
@@ -44,10 +46,14 @@ public function getTradeName(): ?string
     }
 
     /**
-     * @return Address[]
+     * @return array<Address>|null
      */
     public function getAddresses(): ?array
     {
+        if ($this->addresses === null) {
+            return null;
+        }
+
         $addresses = [];
 
         foreach ($this->addresses as $address) {
@@ -64,11 +70,17 @@ public function getAddresses(): ?array
         return $addresses;
     }
 
-    public function getWebsites(): array
+    /**
+     * @return array<string>|null
+     */
+    public function getWebsites(): ?array
     {
         return $this->websites;
     }
 
+    /**
+     * @return array<string, mixed>
+     */
     public function get(): array
     {
         return [