diff --git a/src/Contracts/TransporterContract.php b/src/Contracts/TransporterContract.php
index 4b077ceb..ad5edce6 100644
--- a/src/Contracts/TransporterContract.php
+++ b/src/Contracts/TransporterContract.php
@@ -7,6 +7,7 @@
 use OpenAI\Exceptions\ErrorException;
 use OpenAI\Exceptions\TransporterException;
 use OpenAI\Exceptions\UnserializableResponse;
+use OpenAI\ValueObjects\Transporter\AdaptableResponse;
 use OpenAI\ValueObjects\Transporter\Payload;
 use OpenAI\ValueObjects\Transporter\Response;
 use Psr\Http\Message\ResponseInterface;
@@ -17,16 +18,25 @@
 interface TransporterContract
 {
     /**
-     * Sends a request to a server.
+     * Sends a request to a server expecting an object back.
      *
-     * @return Response<array<array-key, mixed>|string>
+     * @return Response<array<array-key, mixed>>
      *
      * @throws ErrorException|UnserializableResponse|TransporterException
      */
     public function requestObject(Payload $payload): Response;
 
     /**
-     * Sends a content request to a server.
+     * Sends a request to a server expecting an adaptable response (object/string) back.
+     *
+     * @return AdaptableResponse<array<array-key, mixed>|string>
+     *
+     * @throws ErrorException|UnserializableResponse|TransporterException
+     */
+    public function requestStringOrObject(Payload $payload): AdaptableResponse;
+
+    /**
+     * Sends a content request to a server expecting a string back.
      *
      * @throws ErrorException|TransporterException
      */
diff --git a/src/Exceptions/UnserializableResponse.php b/src/Exceptions/UnserializableResponse.php
index 2f9d0643..3a34631c 100644
--- a/src/Exceptions/UnserializableResponse.php
+++ b/src/Exceptions/UnserializableResponse.php
@@ -6,13 +6,11 @@
 
 use Exception;
 use JsonException;
+use Psr\Http\Message\ResponseInterface;
 
 final class UnserializableResponse extends Exception
 {
-    /**
-     * Creates a new Exception instance.
-     */
-    public function __construct(JsonException $exception)
+    public function __construct(JsonException $exception, public ResponseInterface $response)
     {
         parent::__construct($exception->getMessage(), 0, $exception);
     }
diff --git a/src/Resources/Audio.php b/src/Resources/Audio.php
index 3e3f7218..545ca8c9 100644
--- a/src/Resources/Audio.php
+++ b/src/Resources/Audio.php
@@ -64,7 +64,7 @@ public function transcribe(array $parameters): TranscriptionResponse
         $payload = Payload::upload('audio/transcriptions', $parameters);
 
         /** @var Response<array{task: ?string, language: ?string, duration: ?float, segments: array<int, array{id: int, seek: int, start: float, end: float, text: string, tokens: array<int, int>, temperature: float, avg_logprob: float, compression_ratio: float, no_speech_prob: float, transient?: bool}>, words: array<int, array{word: string, start: float, end: float}>, text: string}> $response */
-        $response = $this->transporter->requestObject($payload);
+        $response = $this->transporter->requestStringOrObject($payload);
 
         return TranscriptionResponse::from($response->data(), $response->meta());
     }
@@ -100,7 +100,7 @@ public function translate(array $parameters): TranslationResponse
         $payload = Payload::upload('audio/translations', $parameters);
 
         /** @var Response<array{task: ?string, language: ?string, duration: ?float, segments: array<int, array{id: int, seek: int, start: float, end: float, text: string, tokens: array<int, int>, temperature: float, avg_logprob: float, compression_ratio: float, no_speech_prob: float, transient?: bool}>, text: string}> $response */
-        $response = $this->transporter->requestObject($payload);
+        $response = $this->transporter->requestStringOrObject($payload);
 
         return TranslationResponse::from($response->data(), $response->meta());
     }
diff --git a/src/Responses/Audio/SpeechStreamResponse.php b/src/Responses/Audio/SpeechStreamResponse.php
index b1f5166d..16e43576 100644
--- a/src/Responses/Audio/SpeechStreamResponse.php
+++ b/src/Responses/Audio/SpeechStreamResponse.php
@@ -32,7 +32,6 @@ public function getIterator(): Generator
 
     public function meta(): MetaInformation
     {
-        // @phpstan-ignore-next-line
         return MetaInformation::from($this->response->getHeaders());
     }
 
@@ -44,7 +43,9 @@ public static function fake(?string $content = null, ?MetaInformation $meta = nu
 
         if ($meta instanceof \OpenAI\Responses\Meta\MetaInformation) {
             foreach ($meta->toArray() as $key => $value) {
-                $response = $response->withHeader($key, (string) $value);
+                if (is_scalar($value)) {
+                    $response = $response->withHeader($key, (string) $value);
+                }
             }
         }
 
diff --git a/src/Responses/Meta/MetaInformation.php b/src/Responses/Meta/MetaInformation.php
index 4eec8f67..f5721373 100644
--- a/src/Responses/Meta/MetaInformation.php
+++ b/src/Responses/Meta/MetaInformation.php
@@ -6,12 +6,12 @@
 use OpenAI\Responses\Concerns\ArrayAccessible;
 
 /**
- * @implements MetaInformationContract<array{x-request-id?: string, openai-model?: string, openai-organization?: string, openai-processing-ms?: int, openai-version?: string, x-ratelimit-limit-requests?: int, x-ratelimit-limit-tokens?: int, x-ratelimit-remaining-requests?: int, x-ratelimit-remaining-tokens?: int, x-ratelimit-reset-requests?: string, x-ratelimit-reset-tokens?: string}>
+ * @implements MetaInformationContract<array{x-request-id?: string, openai-model?: string, openai-organization?: string, openai-project?: string, openai-processing-ms?: int, openai-version?: string, x-ratelimit-limit-requests?: int, x-ratelimit-limit-tokens?: int, x-ratelimit-remaining-requests?: int, x-ratelimit-remaining-tokens?: int, x-ratelimit-reset-requests?: string, x-ratelimit-reset-tokens?: string, custom?: array<string, string>}>
  */
 final class MetaInformation implements MetaInformationContract
 {
     /**
-     * @use ArrayAccessible<array{x-request-id?: string, openai-model?: string, openai-organization?: string, openai-processing-ms?: int, openai-version?: string, x-ratelimit-limit-requests?: int, x-ratelimit-limit-tokens?: int, x-ratelimit-remaining-requests?: int, x-ratelimit-remaining-tokens?: int, x-ratelimit-reset-requests?: string, x-ratelimit-reset-tokens?: string}>
+     * @use ArrayAccessible<array{x-request-id?: string, openai-model?: string, openai-organization?: string, openai-project?: string, openai-processing-ms?: int, openai-version?: string, x-ratelimit-limit-requests?: int, x-ratelimit-limit-tokens?: int, x-ratelimit-remaining-requests?: int, x-ratelimit-remaining-tokens?: int, x-ratelimit-reset-requests?: string, x-ratelimit-reset-tokens?: string, custom?: array<string, string>}>
      */
     use ArrayAccessible;
 
@@ -20,13 +20,29 @@ private function __construct(
         public readonly MetaInformationOpenAI $openai,
         public readonly ?MetaInformationRateLimit $requestLimit,
         public readonly ?MetaInformationRateLimit $tokenLimit,
+        public readonly MetaInformationCustom $custom,
     ) {}
 
     /**
-     * @param  array{x-request-id: string[], openai-model: string[], openai-organization: string[], openai-version: string[], openai-processing-ms: string[], x-ratelimit-limit-requests: string[], x-ratelimit-remaining-requests: string[], x-ratelimit-reset-requests: string[], x-ratelimit-limit-tokens: string[], x-ratelimit-remaining-tokens: string[], x-ratelimit-reset-tokens: string[]}  $headers
+     * @param  array<string, array<int, string>>  $headers
      */
     public static function from(array $headers): self
     {
+        $knownHeaders = [
+            'x-request-id',
+            'openai-model',
+            'openai-organization',
+            'openai-project',
+            'openai-version',
+            'openai-processing-ms',
+            'x-ratelimit-limit-requests',
+            'x-ratelimit-remaining-requests',
+            'x-ratelimit-reset-requests',
+            'x-ratelimit-limit-tokens',
+            'x-ratelimit-remaining-tokens',
+            'x-ratelimit-reset-tokens',
+        ];
+
         $headers = array_change_key_case($headers, CASE_LOWER);
 
         $requestId = $headers['x-request-id'][0] ?? null;
@@ -34,6 +50,7 @@ public static function from(array $headers): self
         $openai = MetaInformationOpenAI::from([
             'model' => $headers['openai-model'][0] ?? null,
             'organization' => $headers['openai-organization'][0] ?? null,
+            'project' => $headers['openai-project'][0] ?? null,
             'version' => $headers['openai-version'][0] ?? null,
             'processingMs' => isset($headers['openai-processing-ms'][0]) ? (int) $headers['openai-processing-ms'][0] : null,
         ]);
@@ -58,11 +75,23 @@ public static function from(array $headers): self
             $tokenLimit = null;
         }
 
+        $customHeaders = [];
+        foreach ($headers as $name => $values) {
+            if (in_array($name, $knownHeaders, true)) {
+                continue;
+            }
+
+            $customHeaders[$name] = $values[0] ?? null;
+        }
+
+        $custom = MetaInformationCustom::from($customHeaders);
+
         return new self(
             $requestId,
             $openai,
             $requestLimit,
             $tokenLimit,
+            $custom,
         );
     }
 
@@ -74,6 +103,7 @@ public function toArray(): array
         return array_filter([
             'openai-model' => $this->openai->model,
             'openai-organization' => $this->openai->organization,
+            'openai-project' => $this->openai->project,
             'openai-processing-ms' => $this->openai->processingMs,
             'openai-version' => $this->openai->version,
             'x-ratelimit-limit-requests' => $this->requestLimit->limit ?? null,
@@ -83,6 +113,7 @@ public function toArray(): array
             'x-ratelimit-reset-requests' => $this->requestLimit->reset ?? null,
             'x-ratelimit-reset-tokens' => $this->tokenLimit->reset ?? null,
             'x-request-id' => $this->requestId,
-        ], fn (string|int|null $value): bool => ! is_null($value));
+            'custom' => ! $this->custom->isEmpty() ? $this->custom->toArray() : null,
+        ], fn (array|string|int|null $value): bool => ! is_null($value));
     }
 }
diff --git a/src/Responses/Meta/MetaInformationCustom.php b/src/Responses/Meta/MetaInformationCustom.php
new file mode 100644
index 00000000..59faca3e
--- /dev/null
+++ b/src/Responses/Meta/MetaInformationCustom.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace OpenAI\Responses\Meta;
+
+final readonly class MetaInformationCustom
+{
+    /**
+     * @param  array<string, string>  $headers
+     */
+    private function __construct(
+        public array $headers
+    ) {}
+
+    /**
+     * @param  array<string, string|null>  $headers
+     */
+    public static function from(array $headers): self
+    {
+        return new self(array_filter($headers));
+    }
+
+    /**
+     * @return array<string, string>
+     */
+    public function toArray(): array
+    {
+        return $this->headers;
+    }
+
+    public function isEmpty(): bool
+    {
+        return $this->headers === [];
+    }
+}
diff --git a/src/Responses/Meta/MetaInformationOpenAI.php b/src/Responses/Meta/MetaInformationOpenAI.php
index 879df149..7671df2d 100644
--- a/src/Responses/Meta/MetaInformationOpenAI.php
+++ b/src/Responses/Meta/MetaInformationOpenAI.php
@@ -7,18 +7,20 @@ final class MetaInformationOpenAI
     private function __construct(
         public readonly ?string $model,
         public readonly ?string $organization,
+        public readonly ?string $project,
         public readonly ?string $version,
         public readonly ?int $processingMs,
     ) {}
 
     /**
-     * @param  array{model: ?string, organization: ?string, version: ?string, processingMs: ?int}  $attributes
+     * @param  array{model: ?string, organization: ?string, project: ?string, version: ?string, processingMs: ?int}  $attributes
      */
     public static function from(array $attributes): self
     {
         return new self(
             $attributes['model'],
             $attributes['organization'],
+            $attributes['project'],
             $attributes['version'],
             $attributes['processingMs'],
         );
diff --git a/src/Responses/StreamResponse.php b/src/Responses/StreamResponse.php
index 1fa01a46..c50bc65f 100644
--- a/src/Responses/StreamResponse.php
+++ b/src/Responses/StreamResponse.php
@@ -95,7 +95,6 @@ private function readLine(StreamInterface $stream): string
 
     public function meta(): MetaInformation
     {
-        // @phpstan-ignore-next-line
         return MetaInformation::from($this->response->getHeaders());
     }
 }
diff --git a/src/Transporters/HttpTransporter.php b/src/Transporters/HttpTransporter.php
index a2206658..e9573479 100644
--- a/src/Transporters/HttpTransporter.php
+++ b/src/Transporters/HttpTransporter.php
@@ -12,6 +12,7 @@
 use OpenAI\Exceptions\ErrorException;
 use OpenAI\Exceptions\TransporterException;
 use OpenAI\Exceptions\UnserializableResponse;
+use OpenAI\ValueObjects\Transporter\AdaptableResponse;
 use OpenAI\ValueObjects\Transporter\BaseUri;
 use OpenAI\ValueObjects\Transporter\Headers;
 use OpenAI\ValueObjects\Transporter\Payload;
@@ -50,8 +51,31 @@ public function requestObject(Payload $payload): Response
 
         $contents = (string) $response->getBody();
 
+        $this->throwIfJsonError($response, $contents);
+
+        try {
+            /** @var array{error?: array{message: string, type: string, code: string}} $data */
+            $data = json_decode($contents, true, flags: JSON_THROW_ON_ERROR);
+        } catch (JsonException $jsonException) {
+            throw new UnserializableResponse($jsonException, $response);
+        }
+
+        return Response::from($data, $response->getHeaders());
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function requestStringOrObject(Payload $payload): AdaptableResponse
+    {
+        $request = $payload->toRequest($this->baseUri, $this->headers, $this->queryParams);
+
+        $response = $this->sendRequest(fn (): \Psr\Http\Message\ResponseInterface => $this->client->sendRequest($request));
+
+        $contents = (string) $response->getBody();
+
         if (str_contains($response->getHeaderLine('Content-Type'), ContentType::TEXT_PLAIN->value)) {
-            return Response::from($contents, $response->getHeaders());
+            return AdaptableResponse::from($contents, $response->getHeaders());
         }
 
         $this->throwIfJsonError($response, $contents);
@@ -60,10 +84,10 @@ public function requestObject(Payload $payload): Response
             /** @var array{error?: array{message: string, type: string, code: string}} $data */
             $data = json_decode($contents, true, flags: JSON_THROW_ON_ERROR);
         } catch (JsonException $jsonException) {
-            throw new UnserializableResponse($jsonException);
+            throw new UnserializableResponse($jsonException, $response);
         }
 
-        return Response::from($data, $response->getHeaders());
+        return AdaptableResponse::from($data, $response->getHeaders());
     }
 
     /**
@@ -133,7 +157,7 @@ private function throwIfJsonError(ResponseInterface $response, string|ResponseIn
                 throw new ErrorException($response['error'], $statusCode);
             }
         } catch (JsonException $jsonException) {
-            throw new UnserializableResponse($jsonException);
+            throw new UnserializableResponse($jsonException, $response);
         }
     }
 }
diff --git a/src/ValueObjects/Transporter/AdaptableResponse.php b/src/ValueObjects/Transporter/AdaptableResponse.php
new file mode 100644
index 00000000..a769747f
--- /dev/null
+++ b/src/ValueObjects/Transporter/AdaptableResponse.php
@@ -0,0 +1,59 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenAI\ValueObjects\Transporter;
+
+use OpenAI\Responses\Meta\MetaInformation;
+
+/**
+ * @template-covariant TData of array|string
+ *
+ * @internal
+ */
+final readonly class AdaptableResponse
+{
+    /**
+     * Creates a new AdaptableResponse value object.
+     *
+     * @param  TData  $data
+     */
+    private function __construct(
+        private array|string $data,
+        private MetaInformation $meta
+    ) {
+        // ..
+    }
+
+    /**
+     * Creates a new AdaptableResponse value object from the given data and meta information.
+     *
+     * @param  TData  $data
+     * @param  array<string, array<int, string>>  $headers
+     * @return AdaptableResponse<TData>
+     */
+    public static function from(array|string $data, array $headers): self
+    {
+        $meta = MetaInformation::from($headers);
+
+        return new self($data, $meta);
+    }
+
+    /**
+     * Returns the response data.
+     *
+     * @return TData
+     */
+    public function data(): array|string
+    {
+        return $this->data;
+    }
+
+    /**
+     * Returns the meta information.
+     */
+    public function meta(): MetaInformation
+    {
+        return $this->meta;
+    }
+}
diff --git a/src/ValueObjects/Transporter/Response.php b/src/ValueObjects/Transporter/Response.php
index 1645ab44..fe64fb02 100644
--- a/src/ValueObjects/Transporter/Response.php
+++ b/src/ValueObjects/Transporter/Response.php
@@ -7,11 +7,11 @@
 use OpenAI\Responses\Meta\MetaInformation;
 
 /**
- * @template-covariant TData of array|string
+ * @template-covariant TData of array
  *
  * @internal
  */
-final class Response
+final readonly class Response
 {
     /**
      * Creates a new Response value object.
@@ -19,8 +19,8 @@ final class Response
      * @param  TData  $data
      */
     private function __construct(
-        private readonly array|string $data,
-        private readonly MetaInformation $meta
+        private array $data,
+        private MetaInformation $meta
     ) {
         // ..
     }
@@ -32,9 +32,8 @@ private function __construct(
      * @param  array<string, array<int, string>>  $headers
      * @return Response<TData>
      */
-    public static function from(array|string $data, array $headers): self
+    public static function from(array $data, array $headers): self
     {
-        // @phpstan-ignore-next-line
         $meta = MetaInformation::from($headers);
 
         return new self($data, $meta);
@@ -45,7 +44,7 @@ public static function from(array|string $data, array $headers): self
      *
      * @return TData
      */
-    public function data(): array|string
+    public function data(): array
     {
         return $this->data;
     }
diff --git a/tests/Arch.php b/tests/Arch.php
index f7c8b14a..b63c7a6d 100644
--- a/tests/Arch.php
+++ b/tests/Arch.php
@@ -19,6 +19,7 @@
     ->expect('OpenAI\Exceptions')
     ->toOnlyUse([
         'Psr\Http\Client',
+        'Psr\Http\Message\ResponseInterface',
     ])->toImplement(Throwable::class);
 
 test('resources')->expect('OpenAI\Resources')->toOnlyUse([
diff --git a/tests/Datasets/RequestMethods.php b/tests/Datasets/RequestMethods.php
new file mode 100644
index 00000000..5786aaf7
--- /dev/null
+++ b/tests/Datasets/RequestMethods.php
@@ -0,0 +1,6 @@
+<?php
+
+dataset('request methods', [
+    'requestObject',
+    'requestStringOrObject',
+]);
diff --git a/tests/Fixtures/Meta.php b/tests/Fixtures/Meta.php
index 469faa54..be8e7ee1 100644
--- a/tests/Fixtures/Meta.php
+++ b/tests/Fixtures/Meta.php
@@ -7,6 +7,7 @@ function metaHeaders(): array
     return [
         'openai-model' => ['gpt-3.5-turbo-instruct'],
         'openai-organization' => ['org-1234'],
+        'openai-project' => ['project-5678'],
         'openai-processing-ms' => [410],
         'openai-version' => ['2020-10-01'],
         'x-ratelimit-limit-requests' => [3000],
@@ -41,6 +42,15 @@ function metaHeadersWithDifferentCases(): array
     ];
 }
 
+function metaHeadersWithCustomCases(): array
+{
+    return array_merge(metaHeaders(), [
+        'Custom-Header-One' => ['custom-value-1'],
+        'Custom-Header-Two' => ['custom-value-2'],
+        'Custom-Blank-Header' => [null],
+    ]);
+}
+
 function meta(): MetaInformation
 {
     return MetaInformation::from(metaHeaders());
diff --git a/tests/Pest.php b/tests/Pest.php
index e8d8de39..5105b75c 100644
--- a/tests/Pest.php
+++ b/tests/Pest.php
@@ -3,6 +3,7 @@
 use OpenAI\Client;
 use OpenAI\Contracts\TransporterContract;
 use OpenAI\ValueObjects\ApiKey;
+use OpenAI\ValueObjects\Transporter\AdaptableResponse;
 use OpenAI\ValueObjects\Transporter\BaseUri;
 use OpenAI\ValueObjects\Transporter\Headers;
 use OpenAI\ValueObjects\Transporter\Payload;
@@ -10,7 +11,7 @@
 use OpenAI\ValueObjects\Transporter\Response;
 use Psr\Http\Message\ResponseInterface;
 
-function mockClient(string $method, string $resource, array $params, Response|ResponseInterface|string $response, $methodName = 'requestObject', bool $validateParams = true)
+function mockClient(string $method, string $resource, array $params, Response|AdaptableResponse|ResponseInterface|string $response, $methodName = 'requestObject', bool $validateParams = true)
 {
     $transporter = Mockery::mock(TransporterContract::class);
 
diff --git a/tests/Resources/Audio.php b/tests/Resources/Audio.php
index 574ff214..c6f88079 100644
--- a/tests/Resources/Audio.php
+++ b/tests/Resources/Audio.php
@@ -10,13 +10,14 @@
 use OpenAI\Responses\Audio\TranslationResponseSegment;
 use OpenAI\Responses\Meta\MetaInformation;
 use OpenAI\Responses\StreamResponse;
+use OpenAI\ValueObjects\Transporter\AdaptableResponse;
 
 test('transcribe to text', function () {
     $client = mockClient('POST', 'audio/transcriptions', [
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'text',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranscriptionText(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranscriptionText(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->transcribe([
         'file' => audioFileResource(),
@@ -41,7 +42,7 @@
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'json',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranscriptionJson(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranscriptionJson(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->transcribe([
         'file' => audioFileResource(),
@@ -66,7 +67,7 @@
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'verbose_json',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranscriptionVerboseJson(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranscriptionVerboseJson(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->transcribe([
         'file' => audioFileResource(),
@@ -138,7 +139,7 @@
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'text',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranslationText(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranslationText(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->translate([
         'file' => audioFileResource(),
@@ -163,7 +164,7 @@
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'json',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranslationJson(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranslationJson(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->translate([
         'file' => audioFileResource(),
@@ -188,7 +189,7 @@
         'file' => audioFileResource(),
         'model' => 'whisper-1',
         'response_format' => 'verbose_json',
-    ], \OpenAI\ValueObjects\Transporter\Response::from(audioTranslationVerboseJson(), metaHeaders()), validateParams: false);
+    ], AdaptableResponse::from(audioTranslationVerboseJson(), metaHeaders()), methodName: 'requestStringOrObject', validateParams: false);
 
     $result = $client->audio()->translate([
         'file' => audioFileResource(),
diff --git a/tests/Responses/Meta/MetaInformation.php b/tests/Responses/Meta/MetaInformation.php
index 2aa0138b..8914ed69 100644
--- a/tests/Responses/Meta/MetaInformation.php
+++ b/tests/Responses/Meta/MetaInformation.php
@@ -1,6 +1,7 @@
 <?php
 
 use OpenAI\Responses\Meta\MetaInformation;
+use OpenAI\Responses\Meta\MetaInformationCustom;
 use OpenAI\Responses\Meta\MetaInformationOpenAI;
 use OpenAI\Responses\Meta\MetaInformationRateLimit;
 
@@ -25,6 +26,23 @@
         ->tokenLimit->reset->toBe('2ms');
 });
 
+test('includes custom headers', function () {
+    $headers = metaHeaders();
+    $headers['x-custom-foo'] = ['bar'];
+    $headers['Another-Header'] = ['baz'];
+
+    $meta = MetaInformation::from((new \GuzzleHttp\Psr7\Response(headers: $headers))->getHeaders());
+
+    $array = $meta->toArray();
+
+    expect($array['custom'])
+        ->toBeArray()
+        ->toHaveKey('x-custom-foo', 'bar')
+        ->toHaveKey('another-header', 'baz');
+
+    expect($meta['custom']['x-custom-foo'])->toBe('bar');
+});
+
 test('from response headers without "x-request-id"', function () {
     $headers = metaHeaders();
     unset($headers['x-request-id']);
@@ -97,6 +115,22 @@
         ->tokenLimit->toBeNull();
 });
 
+test('from response headers with custom headers', function () {
+    $meta = MetaInformation::from((new \GuzzleHttp\Psr7\Response(headers: metaHeadersWithCustomCases()))->getHeaders());
+
+    expect($meta)
+        ->toBeInstanceOf(MetaInformation::class)
+        ->requestId->toBe('3813fa4fa3f17bdf0d7654f0f49ebab4')
+        ->custom->toBeInstanceOf(MetaInformationCustom::class);
+
+    expect($meta->custom)
+        ->headers->toBeArray();
+
+    expect($meta->custom->headers)
+        ->toHaveKey('custom-header-one')
+        ->toHaveKey('custom-header-two');
+});
+
 test('as array accessible', function () {
     $meta = MetaInformation::from(metaHeaders());
 
@@ -111,6 +145,7 @@
         ->toBe([
             'openai-model' => 'gpt-3.5-turbo-instruct',
             'openai-organization' => 'org-1234',
+            'openai-project' => 'project-5678',
             'openai-processing-ms' => 410,
             'openai-version' => '2020-10-01',
             'x-ratelimit-limit-requests' => 3000,
diff --git a/tests/Transporters/HttpTransporter.php b/tests/Transporters/HttpTransporter.php
index 4fd772af..b8063f1c 100644
--- a/tests/Transporters/HttpTransporter.php
+++ b/tests/Transporters/HttpTransporter.php
@@ -7,6 +7,7 @@
 use OpenAI\Exceptions\ErrorException;
 use OpenAI\Exceptions\TransporterException;
 use OpenAI\Exceptions\UnserializableResponse;
+use OpenAI\Responses\Models\ListResponse;
 use OpenAI\Transporters\HttpTransporter;
 use OpenAI\ValueObjects\ApiKey;
 use OpenAI\ValueObjects\Transporter\BaseUri;
@@ -31,7 +32,7 @@
     );
 });
 
-test('request object', function () {
+test('request object', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $response = new Response(200, ['Content-Type' => 'application/json; charset=utf-8', ...metaHeaders()], json_encode([
@@ -51,10 +52,10 @@
             return true;
         })->andReturn($response);
 
-    $this->http->requestObject($payload);
-});
+    $this->http->$requestMethod($payload);
+})->with('request methods');
 
-test('request object response', function () {
+test('request object response', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $response = new Response(200, ['Content-Type' => 'application/json; charset=utf-8', ...metaHeaders()], json_encode([
@@ -71,7 +72,7 @@
         ->once()
         ->andReturn($response);
 
-    $response = $this->http->requestObject($payload);
+    $response = $this->http->$requestMethod($payload);
 
     expect($response->data())->toBe([
         [
@@ -81,9 +82,9 @@
             'finish_reason' => 'length',
         ],
     ]);
-});
+})->with('request methods');
 
-test('request object server user errors', function () {
+test('request object server user errors', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $response = new Response(401, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -100,7 +101,7 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('Incorrect API key provided: foo. You can find your API key at https://platform.openai.com.')
                 ->and($e->getErrorMessage())->toBe('Incorrect API key provided: foo. You can find your API key at https://platform.openai.com.')
@@ -108,7 +109,7 @@
                 ->and($e->getErrorType())->toBe('invalid_request_error')
                 ->and($e->getStatusCode())->toBe(401);
         });
-});
+})->with('request methods');
 
 test('request object server errors', function () {
     $payload = Payload::create('completions', ['model' => 'gpt-4']);
@@ -136,7 +137,7 @@
         });
 });
 
-test('error code may be null', function () {
+test('error code may be null', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-42']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -153,16 +154,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('The model `gpt-42` does not exist')
                 ->and($e->getErrorMessage())->toBe('The model `gpt-42` does not exist')
                 ->and($e->getErrorCode())->toBeNull()
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('error code may be integer', function () {
+test('error code may be integer', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-42']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -179,16 +180,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('The model `gpt-42` does not exist')
                 ->and($e->getErrorMessage())->toBe('The model `gpt-42` does not exist')
                 ->and($e->getErrorCode())->toBe(123)
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('error type may be null', function () {
+test('error type may be null', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $response = new Response(429, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -205,16 +206,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('You exceeded your current quota, please check')
                 ->and($e->getErrorMessage())->toBe('You exceeded your current quota, please check')
                 ->and($e->getErrorCode())->toBe('quota_exceeded')
                 ->and($e->getErrorType())->toBeNull();
         });
-});
+})->with('request methods');
 
-test('error message may be an array', function () {
+test('error message may be an array', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-4']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -234,16 +235,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('Invalid schema for function \'get_current_weather\':'.PHP_EOL.'In context=(\'properties\', \'location\'), array schema missing items')
                 ->and($e->getErrorMessage())->toBe('Invalid schema for function \'get_current_weather\':'.PHP_EOL.'In context=(\'properties\', \'location\'), array schema missing items')
                 ->and($e->getErrorCode())->toBeNull()
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('error message may be empty', function () {
+test('error message may be empty', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-4']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -260,16 +261,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('invalid_api_key')
                 ->and($e->getErrorMessage())->toBe('invalid_api_key')
                 ->and($e->getErrorCode())->toBe('invalid_api_key')
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('error message may be empty and code is an integer', function () {
+test('error message may be empty and code is an integer', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-4']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -286,16 +287,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('123')
                 ->and($e->getErrorMessage())->toBe('123')
                 ->and($e->getErrorCode())->toBe(123)
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('error message and code may be empty', function () {
+test('error message and code may be empty', function (string $requestMethod) {
     $payload = Payload::create('completions', ['model' => 'gpt-4']);
 
     $response = new Response(404, ['Content-Type' => 'application/json; charset=utf-8'], json_encode([
@@ -312,16 +313,16 @@
         ->once()
         ->andReturn($response);
 
-    expect(fn () => $this->http->requestObject($payload))
+    expect(fn () => $this->http->$requestMethod($payload))
         ->toThrow(function (ErrorException $e) {
             expect($e->getMessage())->toBe('Unknown error')
                 ->and($e->getErrorMessage())->toBe('Unknown error')
                 ->and($e->getErrorCode())->toBeNull()
                 ->and($e->getErrorType())->toBe('invalid_request_error');
         });
-});
+})->with('request methods');
 
-test('request object client errors', function () {
+test('request object client errors', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $baseUri = BaseUri::from('api.openai.com');
@@ -333,14 +334,14 @@
         ->once()
         ->andThrow(new ConnectException('Could not resolve host.', $payload->toRequest($baseUri, $headers, $queryParams)));
 
-    expect(fn () => $this->http->requestObject($payload))->toThrow(function (TransporterException $e) {
+    expect(fn () => $this->http->$requestMethod($payload))->toThrow(function (TransporterException $e) {
         expect($e->getMessage())->toBe('Could not resolve host.')
             ->and($e->getCode())->toBe(0)
             ->and($e->getPrevious())->toBeInstanceOf(ConnectException::class);
     });
-});
+})->with('request methods');
 
-test('request object client error in response', function () {
+test('request object client error in response', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $baseUri = BaseUri::from('api.openai.com');
@@ -363,13 +364,13 @@
             ]))
         ));
 
-    expect(fn () => $this->http->requestObject($payload))->toThrow(function (ErrorException $e) {
+    expect(fn () => $this->http->$requestMethod($payload))->toThrow(function (ErrorException $e) {
         expect($e->getMessage())
             ->toBe('Incorrect API key provided: foo. You can find your API key at https://platform.openai.com.');
     });
-});
+})->with('request methods');
 
-test('request object serialization errors', function () {
+test('request object serialization errors', function (string $requestMethod) {
     $payload = Payload::list('models');
 
     $response = new Response(200, ['Content-Type' => 'application/json; charset=utf-8'], 'err');
@@ -379,10 +380,24 @@
         ->once()
         ->andReturn($response);
 
-    $this->http->requestObject($payload);
+    $this->http->$requestMethod($payload);
+})->with('request methods')->throws(UnserializableResponse::class, 'Syntax error', 0);
+
+test('request object invalid server 404 html', function () {
+    $payload = Payload::list('models');
+
+    $response = new Response(404, ['Content-Type' => 'text/plain; charset=utf-8'], '404 page not found');
+
+    $this->client
+        ->shouldReceive('sendRequest')
+        ->once()
+        ->andReturn($response);
+
+    $response = $this->http->requestObject($payload);
+    ListResponse::from($response->data(), $response->meta());
 })->throws(UnserializableResponse::class, 'Syntax error', 0);
 
-test('request plain text', function () {
+test('request string or object text', function () {
     $payload = Payload::upload('audio/transcriptions', []);
 
     $response = new Response(200, ['Content-Type' => 'text/plain; charset=utf-8', ...metaHeaders()], 'Hello, how are you?');
@@ -392,7 +407,7 @@
         ->once()
         ->andReturn($response);
 
-    $response = $this->http->requestObject($payload);
+    $response = $this->http->requestStringOrObject($payload);
 
     expect($response->data())->toBe('Hello, how are you?');
 });