diff --git a/README.md b/README.md
index 944bc3b..9448a80 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ _This library is not developed or endorsed by Google._
   - [Tokens counting](#tokens-counting)
   - [Listing models](#listing-models)
   - [Advanced Usages](#advanced-usages)
+    - [Using Beta version](#using-beta-version)
     - [Safety Settings and Generation Configuration](#safety-settings-and-generation-configuration)
     - [Using your own HTTP client](#using-your-own-http-client)
     - [Using your own HTTP client for streaming responses](#using-your-own-http-client-for-streaming-responses)
@@ -52,10 +53,11 @@ you need to allow `php-http/discovery` composer plugin or install a PSR-18 compa
 
 ```php
 use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $client = new Client('GEMINI_API_KEY');
-$response = $client->geminiPro()->generateContent(
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->generateContent(
     new TextPart('PHP in less than 100 chars'),
 );
 
@@ -71,11 +73,12 @@ print $response->text();
 ```php
 use GeminiAPI\Client;
 use GeminiAPI\Enums\MimeType;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\ImagePart;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $client = new Client('GEMINI_API_KEY');
-$response = $client->geminiProVision()->generateContent(
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->generateContent(
     new TextPart('Explain what is in the image'),
     new ImagePart(
         MimeType::IMAGE_JPEG,
@@ -94,10 +97,11 @@ print $response->text();
 
 ```php
 use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $client = new Client('GEMINI_API_KEY');
-$chat = $client->geminiPro()->startChat();
+$chat = $client->generativeModel(ModelName::GEMINI_PRO)->startChat();
 
 $response = $chat->sendMessage(new TextPart('Hello World in PHP'));
 print $response->text();
@@ -132,6 +136,7 @@ This code will print "Hello World!" to the standard output.
 use GeminiAPI\Client;
 use GeminiAPI\Enums\Role;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $history = [
@@ -149,7 +154,7 @@ $history = [
 ];
 
 $client = new Client('GEMINI_API_KEY');
-$chat = $client->geminiPro()
+$chat = $client->generativeModel(ModelName::GEMINI_PRO)
     ->startChat()
     ->withHistory($history);
 
@@ -179,6 +184,7 @@ Long responses may be broken into separate responses, and you can start receivin
 
 ```php
 use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GeminiAPI\Responses\GenerateContentResponse;
 
@@ -191,7 +197,7 @@ $callback = function (GenerateContentResponse $response): void {
 };
 
 $client = new Client('GEMINI_API_KEY');
-$client->geminiPro()->generateContentStream(
+$client->generativeModel(ModelName::GEMINI_PRO)->generateContentStream(
     $callback,
     [new TextPart('PHP in less than 100 chars')],
 );
@@ -209,6 +215,7 @@ $client->geminiPro()->generateContentStream(
 use GeminiAPI\Client;
 use GeminiAPI\Enums\Role;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GeminiAPI\Responses\GenerateContentResponse;
 
@@ -235,7 +242,7 @@ $callback = function (GenerateContentResponse $response): void {
 };
 
 $client = new Client('GEMINI_API_KEY');
-$chat = $client->geminiPro()
+$chat = $client->generativeModel(ModelName::GEMINI_PRO)
     ->startChat()
     ->withHistory($history);
 
@@ -261,11 +268,11 @@ This code will print "Hello World!" to the standard output.
 
 ```php
 use GeminiAPI\Client;
-use GeminiAPI\Enums\ModelName;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $client = new Client('GEMINI_API_KEY');
-$response = $client->embeddingModel(ModelName::Embedding)
+$response = $client->embeddingModel(ModelName::EMBEDDING_001)
     ->embedContent(
         new TextPart('PHP in less than 100 chars'),
     );
@@ -282,10 +289,11 @@ print_r($response->embedding->values);
 
 ```php
 use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 
 $client = new Client('GEMINI_API_KEY');
-$response = $client->geminiPro()->countTokens(
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->countTokens(
     new TextPart('PHP in less than 100 chars'),
 );
 
@@ -322,6 +330,23 @@ print_r($response->models);
 
 ### Advanced Usages
 
+#### Using Beta version
+
+```php
+use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
+use GeminiAPI\Resources\Parts\TextPart;
+
+$client = (new Client('GEMINI_API_KEY'))
+    ->withV1BetaVersion();
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->countTokens(
+    new TextPart('PHP in less than 100 chars'),
+);
+
+print $response->totalTokens;
+// 10
+```
+
 #### Safety Settings and Generation Configuration
 
 ```php
@@ -329,6 +354,7 @@ use GeminiAPI\Client;
 use GeminiAPI\Enums\HarmCategory;
 use GeminiAPI\Enums\HarmBlockThreshold;
 use GeminiAPI\GenerationConfig;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GeminiAPI\SafetySetting;
 
@@ -345,7 +371,7 @@ $generationConfig = (new GenerationConfig())
     ->withStopSequences(['STOP']);
 
 $client = new Client('GEMINI_API_KEY');
-$response = $client->geminiPro()
+$response = $client->generativeModel(ModelName::GEMINI_PRO)
     ->withAddedSafetySetting($safetySetting)
     ->withGenerationConfig($generationConfig)
     ->generateContent(
@@ -357,6 +383,7 @@ $response = $client->geminiPro()
 
 ```php
 use GeminiAPI\Client as GeminiClient;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GuzzleHttp\Client as GuzzleClient;
 
@@ -365,7 +392,7 @@ $guzzle = new GuzzleClient([
 ]);
 
 $client = new GeminiClient('GEMINI_API_KEY', $guzzle);
-$response = $client->geminiPro()->generateContent(
+$response = $client->generativeModel(ModelName::GEMINI_PRO)->generateContent(
     new TextPart('PHP in less than 100 chars')
 );
 ```
@@ -388,6 +415,7 @@ You can also pass the headers you want to be used in the requests.
 
 ```php
 use GeminiAPI\Client;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GeminiAPI\Responses\GenerateContentResponse;
 
@@ -402,7 +430,7 @@ $client = new Client('GEMINI_API_KEY');
 $client->withRequestHeaders([
         'User-Agent' => 'My Gemini-backed app'
     ])
-    ->geminiPro()
+    ->generativeModel(ModelName::GEMINI_PRO)
     ->generateContentStream(
         $callback,
         [new TextPart('PHP in less than 100 chars')],
diff --git a/src/ChatSession.php b/src/ChatSession.php
index 013b9c7..34f3ae6 100644
--- a/src/ChatSession.php
+++ b/src/ChatSession.php
@@ -37,7 +37,7 @@ public function sendMessage(PartInterface ...$parts): GenerateContentResponse
             ->withGenerationConfig($config)
             ->generateContentWithContents($this->history);
 
-        if(!empty($response->candidates)) {
+        if (!empty($response->candidates)) {
             $parts = $response->candidates[0]->content->parts;
             $this->history[] = new Content($parts, Role::Model);
         }
@@ -58,7 +58,7 @@ public function sendMessageStream(
 
         $parts = [];
         $partsCollectorCallback = function (GenerateContentResponse $response) use ($callback, &$parts) {
-            if(!empty($response->candidates)) {
+            if (!empty($response->candidates)) {
                 array_push($parts, ...$response->parts());
             }
 
diff --git a/src/Client.php b/src/Client.php
index c4a3544..9db1d12 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -40,6 +40,7 @@
 class Client implements GeminiClientInterface
 {
     private string $baseUrl = 'https://generativelanguage.googleapis.com';
+    private string $version = GeminiClientInterface::API_VERSION_V1;
 
     /**
      * @var array<string, string|string[]>
@@ -87,7 +88,7 @@ public function geminiProFlash1_5(): GenerativeModel
     }
 
 
-    public function generativeModel(ModelName $modelName): GenerativeModel
+    public function generativeModel(ModelName|string $modelName): GenerativeModel
     {
         return new GenerativeModel(
             $this,
@@ -95,7 +96,7 @@ public function generativeModel(ModelName $modelName): GenerativeModel
         );
     }
 
-    public function embeddingModel(ModelName $modelName): EmbeddingModel
+    public function embeddingModel(ModelName|string $modelName): EmbeddingModel
     {
         return new EmbeddingModel(
             $this,
@@ -163,7 +164,7 @@ public function generateContentStream(
             }
         }
 
-        curl_setopt($ch, CURLOPT_URL, "{$this->baseUrl}/v1/{$request->getOperation()}");
+        curl_setopt($ch, CURLOPT_URL, $this->getRequestUrl($request));
         curl_setopt($ch, CURLOPT_POST, true);
         curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($request));
         curl_setopt($ch, CURLOPT_HTTPHEADER, $headerLines);
@@ -214,6 +215,19 @@ public function withBaseUrl(string $baseUrl): self
         return $clone;
     }
 
+    public function withV1BetaVersion(): self
+    {
+        return $this->withVersion(GeminiClientInterface::API_VERSION_V1_BETA);
+    }
+
+    public function withVersion(string $version): self
+    {
+        $clone = clone $this;
+        $clone->version = $version;
+
+        return $clone;
+    }
+
     /**
      * @param array<string, string|string[]> $headers
      * @return self
@@ -241,6 +255,16 @@ private function getRequestHeaders(): array
         ];
     }
 
+    private function getRequestUrl(RequestInterface $request): string
+    {
+        return sprintf(
+            '%s/%s/%s',
+            $this->baseUrl,
+            $this->version,
+            $request->getOperation(),
+        );
+    }
+
     /**
      * @throws ClientExceptionInterface
      */
@@ -250,9 +274,11 @@ private function doRequest(RequestInterface $request): string
             throw new RuntimeException('Missing client or factory for Gemini API operation');
         }
 
-        $uri = "{$this->baseUrl}/v1/{$request->getOperation()}";
         $httpRequest = $this->requestFactory
-            ->createRequest($request->getHttpMethod(), $uri);
+            ->createRequest(
+                $request->getHttpMethod(),
+                $this->getRequestUrl($request),
+            );
 
         foreach ($this->getRequestHeaders() as $name => $value) {
             $httpRequest = $httpRequest->withAddedHeader($name, $value);
diff --git a/src/ClientInterface.php b/src/ClientInterface.php
index 2d5cbec..edc2094 100644
--- a/src/ClientInterface.php
+++ b/src/ClientInterface.php
@@ -21,12 +21,14 @@
 interface ClientInterface
 {
     public const API_KEY_HEADER_NAME = 'x-goog-api-key';
+    public const API_VERSION_V1 = 'v1';
+    public const API_VERSION_V1_BETA = 'v1beta';
 
     public function countTokens(CountTokensRequest $request): CountTokensResponse;
     public function generateContent(GenerateContentRequest $request): GenerateContentResponse;
     public function embedContent(EmbedContentRequest $request): EmbedContentResponse;
-    public function generativeModel(ModelName $modelName): GenerativeModel;
-    public function embeddingModel(ModelName $modelName): EmbeddingModel;
+    public function generativeModel(ModelName|string $modelName): GenerativeModel;
+    public function embeddingModel(ModelName|string $modelName): EmbeddingModel;
     public function listModels(): ListModelsResponse;
     public function withBaseUrl(string $baseUrl): self;
 
diff --git a/src/EmbeddingModel.php b/src/EmbeddingModel.php
index 384977b..dc35952 100644
--- a/src/EmbeddingModel.php
+++ b/src/EmbeddingModel.php
@@ -19,7 +19,7 @@ class EmbeddingModel
 
     public function __construct(
         private readonly Client $client,
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
     ) {
     }
 
diff --git a/src/Enums/ModelName.php b/src/Enums/ModelName.php
index 5103ae2..df2dd00 100644
--- a/src/Enums/ModelName.php
+++ b/src/Enums/ModelName.php
@@ -4,6 +4,9 @@
 
 namespace GeminiAPI\Enums;
 
+/**
+ * @deprecated Use constants from GeminiAPI\Resources\ModelName instead
+ */
 enum ModelName: string
 {
     case Default = 'models/text-bison-001';
diff --git a/src/GenerativeModel.php b/src/GenerativeModel.php
index 0108f35..46f9fc1 100644
--- a/src/GenerativeModel.php
+++ b/src/GenerativeModel.php
@@ -4,7 +4,6 @@
 
 namespace GeminiAPI;
 
-use BadMethodCallException;
 use CurlHandle;
 use GeminiAPI\Enums\ModelName;
 use GeminiAPI\Enums\Role;
@@ -29,7 +28,7 @@ class GenerativeModel
 
     public function __construct(
         private readonly Client $client,
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
     ) {
     }
 
diff --git a/src/Requests/CountTokensRequest.php b/src/Requests/CountTokensRequest.php
index 911fecf..d33549a 100644
--- a/src/Requests/CountTokensRequest.php
+++ b/src/Requests/CountTokensRequest.php
@@ -5,8 +5,9 @@
 namespace GeminiAPI\Requests;
 
 use GeminiAPI\Enums\ModelName;
-use GeminiAPI\Traits\ArrayTypeValidator;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Traits\ArrayTypeValidator;
+use GeminiAPI\Traits\ModelNameToString;
 use JsonSerializable;
 
 use function json_encode;
@@ -14,13 +15,14 @@
 class CountTokensRequest implements JsonSerializable, RequestInterface
 {
     use ArrayTypeValidator;
+    use ModelNameToString;
 
     /**
-     * @param ModelName $modelName
+     * @param ModelName|string $modelName
      * @param Content[] $contents
      */
     public function __construct(
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
         public readonly array $contents,
     ) {
         $this->ensureArrayOfType($this->contents, Content::class);
@@ -28,7 +30,7 @@ public function __construct(
 
     public function getOperation(): string
     {
-        return "{$this->modelName->value}:countTokens";
+        return "{$this->modelNameToString($this->modelName)}:countTokens";
     }
 
     public function getHttpMethod(): string
@@ -50,7 +52,7 @@ public function getHttpPayload(): string
     public function jsonSerialize(): array
     {
         return [
-            'model' => $this->modelName->value,
+            'model' => $this->modelNameToString($this->modelName),
             'contents' => $this->contents,
         ];
     }
diff --git a/src/Requests/EmbedContentRequest.php b/src/Requests/EmbedContentRequest.php
index 597c6ca..e55334d 100644
--- a/src/Requests/EmbedContentRequest.php
+++ b/src/Requests/EmbedContentRequest.php
@@ -8,22 +8,21 @@
 use GeminiAPI\Enums\ModelName;
 use GeminiAPI\Enums\TaskType;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Traits\ModelNameToString;
 use JsonSerializable;
 
 use function json_encode;
 
 class EmbedContentRequest implements JsonSerializable, RequestInterface
 {
+    use ModelNameToString;
+
     public function __construct(
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
         public readonly Content $content,
         public readonly ?TaskType $taskType = null,
         public readonly ?string $title = null,
     ) {
-        if (isset($this->taskType) && $this->modelName !== ModelName::Embedding) {
-            throw new BadMethodCallException('TaskType can only be set when ModelName is Embedding');
-        }
-
         if (isset($this->title) && $this->taskType !== TaskType::RETRIEVAL_DOCUMENT) {
             throw new BadMethodCallException('Title is only applicable when TaskType is RETRIEVAL_DOCUMENT');
         }
@@ -31,7 +30,7 @@ public function __construct(
 
     public function getOperation(): string
     {
-        return "{$this->modelName->value}:embedContent";
+        return "{$this->modelNameToString($this->modelName)}:embedContent";
     }
 
     public function getHttpMethod(): string
diff --git a/src/Requests/GenerateContentRequest.php b/src/Requests/GenerateContentRequest.php
index a421e3e..d3027b9 100644
--- a/src/Requests/GenerateContentRequest.php
+++ b/src/Requests/GenerateContentRequest.php
@@ -6,9 +6,10 @@
 
 use GeminiAPI\Enums\ModelName;
 use GeminiAPI\GenerationConfig;
+use GeminiAPI\Resources\Content;
 use GeminiAPI\SafetySetting;
 use GeminiAPI\Traits\ArrayTypeValidator;
-use GeminiAPI\Resources\Content;
+use GeminiAPI\Traits\ModelNameToString;
 use JsonSerializable;
 
 use function json_encode;
@@ -16,15 +17,16 @@
 class GenerateContentRequest implements JsonSerializable, RequestInterface
 {
     use ArrayTypeValidator;
+    use ModelNameToString;
 
     /**
-     * @param ModelName $modelName
+     * @param ModelName|string $modelName
      * @param Content[] $contents
      * @param SafetySetting[] $safetySettings
      * @param GenerationConfig|null $generationConfig
      */
     public function __construct(
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
         public readonly array $contents,
         public readonly array $safetySettings = [],
         public readonly ?GenerationConfig $generationConfig = null,
@@ -35,7 +37,7 @@ public function __construct(
 
     public function getOperation(): string
     {
-        return "{$this->modelName->value}:generateContent";
+        return "{$this->modelNameToString($this->modelName)}:generateContent";
     }
 
     public function getHttpMethod(): string
@@ -59,7 +61,7 @@ public function getHttpPayload(): string
     public function jsonSerialize(): array
     {
         $arr = [
-            'model' => $this->modelName->value,
+            'model' => $this->modelNameToString($this->modelName),
             'contents' => $this->contents,
         ];
 
diff --git a/src/Requests/GenerateContentStreamRequest.php b/src/Requests/GenerateContentStreamRequest.php
index 74aac7b..cf19c3a 100644
--- a/src/Requests/GenerateContentStreamRequest.php
+++ b/src/Requests/GenerateContentStreamRequest.php
@@ -6,9 +6,10 @@
 
 use GeminiAPI\Enums\ModelName;
 use GeminiAPI\GenerationConfig;
+use GeminiAPI\Resources\Content;
 use GeminiAPI\SafetySetting;
 use GeminiAPI\Traits\ArrayTypeValidator;
-use GeminiAPI\Resources\Content;
+use GeminiAPI\Traits\ModelNameToString;
 use JsonSerializable;
 
 use function json_encode;
@@ -16,15 +17,16 @@
 class GenerateContentStreamRequest implements JsonSerializable, RequestInterface
 {
     use ArrayTypeValidator;
+    use ModelNameToString;
 
     /**
-     * @param ModelName $modelName
+     * @param ModelName|string $modelName
      * @param Content[] $contents
      * @param SafetySetting[] $safetySettings
      * @param GenerationConfig|null $generationConfig
      */
     public function __construct(
-        public readonly ModelName $modelName,
+        public readonly ModelName|string $modelName,
         public readonly array $contents,
         public readonly array $safetySettings = [],
         public readonly ?GenerationConfig $generationConfig = null,
@@ -35,7 +37,7 @@ public function __construct(
 
     public function getOperation(): string
     {
-        return "{$this->modelName->value}:streamGenerateContent";
+        return "{$this->modelNameToString($this->modelName)}:streamGenerateContent";
     }
 
     public function getHttpMethod(): string
@@ -59,7 +61,7 @@ public function getHttpPayload(): string
     public function jsonSerialize(): array
     {
         $arr = [
-            'model' => $this->modelName->value,
+            'model' => $this->modelNameToString($this->modelName),
             'contents' => $this->contents,
         ];
 
diff --git a/src/Resources/ModelName.php b/src/Resources/ModelName.php
new file mode 100644
index 0000000..84b0bf5
--- /dev/null
+++ b/src/Resources/ModelName.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GeminiAPI\Resources;
+
+class ModelName
+{
+    // Optimized for: Natural language tasks, multi-turn text and code chat, and code generation
+    public const GEMINI_PRO = 'gemini-pro';
+    public const GEMINI_1_0_PRO = 'gemini-1.0-pro';
+    public const GEMINI_1_0_PRO_001 = 'gemini-1.0-pro-001';
+    public const GEMINI_1_0_PRO_LATEST = 'gemini-1.0-pro-latest';
+
+    // Optimized for: Complex reasoning tasks requiring more intelligence
+    public const GEMINI_1_5_PRO = 'gemini-1.5-pro';
+    public const GEMINI_1_5_PRO_001 = 'gemini-1.5-pro-001';
+    public const GEMINI_1_5_PRO_002 = 'gemini-1.5-pro-002';
+    public const GEMINI_1_5_PRO_LATEST = 'gemini-1.5-pro-latest';
+
+    // Optimized for: Fast and versatile performance across a diverse variety of tasks
+    public const GEMINI_1_5_FLASH = 'gemini-1.5-flash';
+    public const GEMINI_1_5_FLASH_001 = 'gemini-1.5-flash-001';
+    public const GEMINI_1_5_FLASH_002 = 'gemini-1.5-flash-002';
+    public const GEMINI_1_5_FLASH_LATEST = 'gemini-1.5-flash-latest';
+
+    // Optimized for: High volume and lower intelligence tasks
+    public const GEMINI_1_5_FLASH_8B = 'gemini-1.5-flash-8b';
+    public const GEMINI_1_5_FLASH_8B_001 = 'gemini-1.5-flash-8b-001';
+    public const GEMINI_1_5_FLASH_8B_LATEST = 'gemini-1.5-flash-8b-latest';
+
+    // Optimized for: Measuring the relatedness of text strings
+    public const TEXT_EMBEDDING_004 = 'text-embedding-004';
+    public const EMBEDDING_001 = 'embedding-001';
+
+    // Optimized for: Providing source-grounded answers to questions
+    public const AQA = 'aqa';
+}
diff --git a/src/Traits/ModelNameToString.php b/src/Traits/ModelNameToString.php
new file mode 100644
index 0000000..07d577c
--- /dev/null
+++ b/src/Traits/ModelNameToString.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace GeminiAPI\Traits;
+
+use GeminiAPI\Enums\ModelName;
+
+trait ModelNameToString
+{
+    private function modelNameToString(ModelName|string $modelName): string
+    {
+        return is_string($modelName) ? "models/$modelName" : $modelName->value;
+    }
+}
diff --git a/tests/Unit/ClientTest.php b/tests/Unit/ClientTest.php
index 1e13609..0e8f25e 100644
--- a/tests/Unit/ClientTest.php
+++ b/tests/Unit/ClientTest.php
@@ -6,12 +6,13 @@
 
 use GeminiAPI\Client;
 use GeminiAPI\ClientInterface as GeminiAPIClientInterface;
-use GeminiAPI\Enums\ModelName;
+use GeminiAPI\Enums\ModelName as ModelNameEnum;
 use GeminiAPI\GenerativeModel;
 use GeminiAPI\Requests\CountTokensRequest;
 use GeminiAPI\Requests\EmbedContentRequest;
 use GeminiAPI\Requests\GenerateContentRequest;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use GuzzleHttp\Psr7\Request;
 use GuzzleHttp\Psr7\Response;
 use GuzzleHttp\Psr7\Utils;
@@ -22,7 +23,7 @@
 
 class ClientTest extends TestCase
 {
-    public function testConstructor()
+    public function testConstructor(): void
     {
         $client = new Client(
             'test-api-key',
@@ -31,7 +32,7 @@ public function testConstructor()
         self::assertInstanceOf(Client::class, $client);
     }
 
-    public function testWithBaseUrl()
+    public function testWithBaseUrl(): void
     {
         $client = new Client(
             'test-api-key',
@@ -41,26 +42,26 @@ public function testWithBaseUrl()
         self::assertInstanceOf(Client::class, $client);
     }
 
-    public function testGeminiPro()
+    public function testGeminiPro(): void
     {
         $client = new Client(
             'test-api-key',
             $this->createMock(HttpClientInterface::class),
         );
-        $model = $client->geminiPro();
+        $model = $client->generativeModel(ModelName::GEMINI_PRO);
         self::assertInstanceOf(GenerativeModel::class, $model);
-        self::assertEquals(ModelName::GeminiPro, $model->modelName);
+        self::assertEquals(ModelName::GEMINI_PRO, $model->modelName);
     }
 
-    public function testGeminiProVision()
+    public function testGeminiProWithEnum(): void
     {
         $client = new Client(
             'test-api-key',
             $this->createMock(HttpClientInterface::class),
         );
-        $model = $client->geminiProVision();
+        $model = $client->generativeModel(ModelNameEnum::GeminiPro);
         self::assertInstanceOf(GenerativeModel::class, $model);
-        self::assertEquals(ModelName::GeminiProVision, $model->modelName);
+        self::assertEquals(ModelNameEnum::GeminiPro, $model->modelName);
     }
 
     public function testGenerativeModel()
@@ -69,12 +70,12 @@ public function testGenerativeModel()
             'test-api-key',
             $this->createMock(HttpClientInterface::class),
         );
-        $model = $client->generativeModel(ModelName::Embedding);
+        $model = $client->generativeModel(ModelName::EMBEDDING_001);
         self::assertInstanceOf(GenerativeModel::class, $model);
-        self::assertEquals(ModelName::Embedding, $model->modelName);
+        self::assertEquals(ModelName::EMBEDDING_001, $model->modelName);
     }
 
-    public function testGenerateContent()
+    public function testGenerateContent(): void
     {
         $httpRequest = new Request(
             'POST',
@@ -144,14 +145,14 @@ public function testGenerateContent()
             $streamFactory,
         );
         $request = new GenerateContentRequest(
-            ModelName::GeminiPro,
+            ModelName::GEMINI_PRO,
             [Content::text('this is a text')],
         );
         $response = $client->generateContent($request);
         self::assertEquals('This is the Gemini Pro response', $response->text());
     }
 
-    public function testEmbedContent()
+    public function testEmbedContent(): void
     {
         $httpRequest = new Request(
             'POST',
@@ -199,14 +200,14 @@ public function testEmbedContent()
             $streamFactory,
         );
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a text'),
         );
         $response = $client->embedContent($request);
         self::assertEquals([0.041395925, -0.017692696], $response->embedding->values);
     }
 
-    public function testCountTokens()
+    public function testCountTokens(): void
     {
         $httpRequest = new Request(
             'POST',
@@ -249,14 +250,14 @@ public function testCountTokens()
             $streamFactory,
         );
         $request = new CountTokensRequest(
-            ModelName::GeminiPro,
+            ModelName::GEMINI_PRO,
             [Content::text('this is a text')],
         );
         $response = $client->countTokens($request);
         self::assertEquals(10, $response->totalTokens);
     }
 
-    public function testListModels()
+    public function testListModels(): void
     {
         $httpRequest = new Request(
             'GET',
diff --git a/tests/Unit/Requests/CountTokensRequestTest.php b/tests/Unit/Requests/CountTokensRequestTest.php
index 9517c63..56763e8 100644
--- a/tests/Unit/Requests/CountTokensRequestTest.php
+++ b/tests/Unit/Requests/CountTokensRequestTest.php
@@ -4,26 +4,26 @@
 
 namespace GeminiAPI\Tests\Unit\Requests;
 
-use GeminiAPI\Enums\ModelName;
 use GeminiAPI\Enums\Role;
 use GeminiAPI\Requests\CountTokensRequest;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use InvalidArgumentException;
 use PHPUnit\Framework\TestCase;
 
 class CountTokensRequestTest extends TestCase
 {
-    public function testConstructorWithNoContents()
+    public function testConstructorWithNoContents(): void
     {
-        $request = new CountTokensRequest(ModelName::Default, []);
+        $request = new CountTokensRequest(ModelName::GEMINI_PRO, []);
         self::assertInstanceOf(CountTokensRequest::class, $request);
     }
 
-    public function testConstructorWithContents()
+    public function testConstructorWithContents(): void
     {
         $request = new CountTokensRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([], Role::User),
                 new Content([], Role::Model),
@@ -33,12 +33,13 @@ public function testConstructorWithContents()
         self::assertInstanceOf(CountTokensRequest::class, $request);
     }
 
-    public function testConstructorWithInvalidContents()
+    public function testConstructorWithInvalidContents(): void
     {
         $this->expectException(InvalidArgumentException::class);
 
         new CountTokensRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
+            // @phpstan-ignore-next-line
             [
                 new Content([], Role::User),
                 new TextPart('This is a text'),
@@ -46,42 +47,42 @@ public function testConstructorWithInvalidContents()
         );
     }
 
-    public function testGetOperation()
+    public function testGetOperation(): void
     {
-        $request = new CountTokensRequest(ModelName::Default, []);
-        self::assertEquals('models/text-bison-001:countTokens', $request->getOperation());
+        $request = new CountTokensRequest(ModelName::GEMINI_PRO, []);
+        self::assertEquals('models/gemini-pro:countTokens', $request->getOperation());
     }
 
-    public function testGetHttpMethod()
+    public function testGetHttpMethod(): void
     {
-        $request = new CountTokensRequest(ModelName::Default, []);
+        $request = new CountTokensRequest(ModelName::GEMINI_PRO, []);
         self::assertEquals('POST', $request->getHttpMethod());
     }
 
-    public function testGetHttpPayload()
+    public function testGetHttpPayload(): void
     {
         $request = new CountTokensRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
         );
 
-        $expected = '{"model":"models\/text-bison-001","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
+        $expected = '{"model":"models\/gemini-pro","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
         self::assertEquals($expected, $request->getHttpPayload());
     }
 
-    public function testJsonSerialize()
+    public function testJsonSerialize(): void
     {
         $request = new CountTokensRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
         );
 
         $expected = [
-            'model' => 'models/text-bison-001',
+            'model' => 'models/gemini-pro',
             'contents' => [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
@@ -89,10 +90,10 @@ public function testJsonSerialize()
         self::assertEquals($expected, $request->jsonSerialize());
     }
 
-    public function test__toString()
+    public function test__toString(): void
     {
         $request = new CountTokensRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content(
                     [new TextPart('This is a text')],
@@ -101,7 +102,7 @@ public function test__toString()
             ],
         );
 
-        $expected = '{"model":"models\/text-bison-001","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
+        $expected = '{"model":"models\/gemini-pro","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
         self::assertEquals($expected, (string) $request);
     }
 }
diff --git a/tests/Unit/Requests/EmbedContentRequestTest.php b/tests/Unit/Requests/EmbedContentRequestTest.php
index e1a0fdb..e6cea4e 100644
--- a/tests/Unit/Requests/EmbedContentRequestTest.php
+++ b/tests/Unit/Requests/EmbedContentRequestTest.php
@@ -5,37 +5,37 @@
 namespace GeminiAPI\Tests\Unit\Requests;
 
 use BadMethodCallException;
-use GeminiAPI\Enums\ModelName;
 use GeminiAPI\Enums\TaskType;
 use GeminiAPI\Requests\EmbedContentRequest;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use PHPUnit\Framework\TestCase;
 
 class EmbedContentRequestTest extends TestCase
 {
-    public function testConstructor()
+    public function testConstructor(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
         );
         self::assertInstanceOf(EmbedContentRequest::class, $request);
     }
 
-    public function testConstructorWithTaskType()
+    public function testConstructorWithTaskType(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
             TaskType::RETRIEVAL_DOCUMENT,
         );
         self::assertInstanceOf(EmbedContentRequest::class, $request);
     }
 
-    public function testConstructorWithTitle()
+    public function testConstructorWithTitle(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
             TaskType::RETRIEVAL_DOCUMENT,
             'this is a title',
@@ -43,62 +43,50 @@ public function testConstructorWithTitle()
         self::assertInstanceOf(EmbedContentRequest::class, $request);
     }
 
-    public function testConstructorWithTaskTypeAndNonEmbeddingModel()
-    {
-        $this->expectException(BadMethodCallException::class);
-        $this->expectExceptionMessage('TaskType can only be set when ModelName is Embedding');
-
-        new EmbedContentRequest(
-            ModelName::GeminiPro,
-            Content::text('this is a test'),
-            TaskType::RETRIEVAL_DOCUMENT,
-        );
-    }
-
-    public function testConstructorWithTitleAndWrongTaskType()
+    public function testConstructorWithTitleAndWrongTaskType(): void
     {
         $this->expectException(BadMethodCallException::class);
         $this->expectExceptionMessage('Title is only applicable when TaskType is RETRIEVAL_DOCUMENT');
 
         new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
             TaskType::RETRIEVAL_QUERY,
             'this is a title',
         );
     }
 
-    public function testGetHttpPayload()
+    public function testGetHttpPayload(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
         );
         self::assertEquals('{"content":{"parts":[{"text":"this is a test"}],"role":"user"}}', $request->getHttpPayload());
     }
 
-    public function testGetHttpMethod()
+    public function testGetHttpMethod(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
         );
         self::assertEquals('POST', $request->getHttpMethod());
     }
 
-    public function testGetOperation()
+    public function testGetOperation(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
         );
         self::assertEquals('models/embedding-001:embedContent', $request->getOperation());
     }
 
-    public function testJsonSerialize()
+    public function testJsonSerialize(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             $content = Content::text('this is a test'),
             TaskType::RETRIEVAL_DOCUMENT,
             'this is a title',
@@ -111,10 +99,10 @@ public function testJsonSerialize()
         self::assertEquals($expected, $request->jsonSerialize());
     }
 
-    public function test__toString()
+    public function test__toString(): void
     {
         $request = new EmbedContentRequest(
-            ModelName::Embedding,
+            ModelName::EMBEDDING_001,
             Content::text('this is a test'),
         );
         self::assertEquals('{"content":{"parts":[{"text":"this is a test"}],"role":"user"}}', (string) $request);
diff --git a/tests/Unit/Requests/GenerateContentRequestTest.php b/tests/Unit/Requests/GenerateContentRequestTest.php
index 62afb95..6c3aead 100644
--- a/tests/Unit/Requests/GenerateContentRequestTest.php
+++ b/tests/Unit/Requests/GenerateContentRequestTest.php
@@ -7,11 +7,11 @@
 use GeminiAPI\Enums\HarmBlockThreshold;
 use GeminiAPI\Enums\HarmCategory;
 use GeminiAPI\Enums\HarmProbability;
-use GeminiAPI\Enums\ModelName;
 use GeminiAPI\Enums\Role;
 use GeminiAPI\GenerationConfig;
 use GeminiAPI\Requests\GenerateContentRequest;
 use GeminiAPI\Resources\Content;
+use GeminiAPI\Resources\ModelName;
 use GeminiAPI\Resources\Parts\TextPart;
 use GeminiAPI\Resources\SafetyRating;
 use GeminiAPI\SafetySetting;
@@ -20,10 +20,10 @@
 
 class GenerateContentRequestTest extends TestCase
 {
-    public function testConstructorWithNoContents()
+    public function testConstructorWithNoContents(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [],
             [],
             null,
@@ -31,10 +31,10 @@ public function testConstructorWithNoContents()
         self::assertInstanceOf(GenerateContentRequest::class, $request);
     }
 
-    public function testConstructorWithContents()
+    public function testConstructorWithContents(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([], Role::User),
                 new Content([], Role::Model),
@@ -45,12 +45,12 @@ public function testConstructorWithContents()
         self::assertInstanceOf(GenerateContentRequest::class, $request);
     }
 
-    public function testConstructorWithInvalidContents()
+    public function testConstructorWithInvalidContents(): void
     {
         $this->expectException(InvalidArgumentException::class);
 
         new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([], Role::User),
                 new TextPart('This is a text'),
@@ -60,10 +60,10 @@ public function testConstructorWithInvalidContents()
         );
     }
 
-    public function testConstructorWithSafetySettings()
+    public function testConstructorWithSafetySettings(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [],
             [
                 new SafetySetting(
@@ -80,12 +80,12 @@ public function testConstructorWithSafetySettings()
         self::assertInstanceOf(GenerateContentRequest::class, $request);
     }
 
-    public function testConstructorWithInvalidSafetySettings()
+    public function testConstructorWithInvalidSafetySettings(): void
     {
         $this->expectException(InvalidArgumentException::class);
 
         new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [],
             [
                 new SafetySetting(
@@ -102,10 +102,10 @@ public function testConstructorWithInvalidSafetySettings()
         );
     }
 
-    public function testConstructorWithGenerationConfig()
+    public function testConstructorWithGenerationConfig(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [],
             [],
             new GenerationConfig(),
@@ -113,41 +113,41 @@ public function testConstructorWithGenerationConfig()
         self::assertInstanceOf(GenerateContentRequest::class, $request);
     }
 
-    public function testGetOperation()
+    public function testGetOperation(): void
     {
-        $request = new GenerateContentRequest(ModelName::Default, []);
-        self::assertEquals('models/text-bison-001:generateContent', $request->getOperation());
+        $request = new GenerateContentRequest(ModelName::GEMINI_PRO, []);
+        self::assertEquals('models/gemini-pro:generateContent', $request->getOperation());
     }
 
-    public function testGetHttpMethod()
+    public function testGetHttpMethod(): void
     {
-        $request = new GenerateContentRequest(ModelName::Default, []);
+        $request = new GenerateContentRequest(ModelName::GEMINI_PRO, []);
         self::assertEquals('POST', $request->getHttpMethod());
     }
 
-    public function testGetHttpPayload()
+    public function testGetHttpPayload(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
         );
-        $expected = '{"model":"models\/text-bison-001","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
+        $expected = '{"model":"models\/gemini-pro","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
         self::assertEquals($expected, $request->getHttpPayload());
     }
 
-    public function testJsonSerialize()
+    public function testJsonSerialize(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
         );
 
         $expected = [
-            'model' => 'models/text-bison-001',
+            'model' => 'models/gemini-pro',
             'contents' => [
                 new Content([new TextPart('This is a text')], Role::User),
             ],
@@ -155,10 +155,10 @@ public function testJsonSerialize()
         self::assertEquals($expected, $request->jsonSerialize());
     }
 
-    public function test__toString()
+    public function test__toString(): void
     {
         $request = new GenerateContentRequest(
-            ModelName::Default,
+            ModelName::GEMINI_PRO,
             [
                 new Content(
                     [new TextPart('This is a text')],
@@ -167,7 +167,7 @@ public function test__toString()
             ],
         );
 
-        $expected = '{"model":"models\/text-bison-001","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
+        $expected = '{"model":"models\/gemini-pro","contents":[{"parts":[{"text":"This is a text"}],"role":"user"}]}';
         self::assertEquals($expected, (string) $request);
     }
 }