Google Gemini API API in PHP

Google Gemini API API in PHP

This guide shows you how to integrate the Google Gemini API into your PHP application. Google’s multimodal AI model for text, image, video, and audio understanding.

Prerequisites

  • PHP installed on your system
  • An Google Gemini API API key (sign up at https://ai.google.dev)
  • Basic familiarity with HTTP APIs

Installation

composer require guzzlehttp/guzzle

Basic Usage

<?php
$apiKey = getenv('API_KEY') ?: 'YOUR_API_KEY';
$baseUrl = 'https://generativelanguage.googleapis.com';

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $baseUrl . '/v1/resources');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Authorization: Bearer ' . $apiKey,
    'Content-Type: application/json',
]);

$response = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

echo "Status: $httpCode\n";
echo $response . "\n";
?>

Error Handling

<?php
$apiKey = getenv('API_KEY') ?: 'YOUR_API_KEY';
$baseUrl = 'https://generativelanguage.googleapis.com';

function callApiWithRetry($url, $headers, $maxRetries = 3) {
    $ch = curl_init();
    for ($attempt = 0; $attempt <= $maxRetries; $attempt++) {
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        if ($httpCode === 429) {
            sleep(60);
            continue;
        }
        if ($httpCode < 500) {
            break;
        }
        sleep(pow(2, $attempt));
    }
    curl_close($ch);
    return [$httpCode, $response];
}

$url = $baseUrl . '/v1/resources';
$headers = ['Authorization: Bearer ' . $apiKey, 'Content-Type: application/json'];
list($code, $resp) = callApiWithRetry($url, $headers);
echo "Status: $code\n";
echo $resp . "\n";
?>

Advanced Usage

<?php
class GeminiClient {
    private $apiKey;
    private $baseUrl;

    public function __construct($apiKey, $baseUrl = 'https://generativelanguage.googleapis.com') {
        $this->apiKey = $apiKey;
        $this->baseUrl = rtrim($baseUrl, '/');
    }

    public function request($method, $path, $data = null) {
        $ch = curl_init();
        $url = $this->baseUrl . '/v1' . $path;
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        curl_setopt($ch, CURLOPT_HTTPHEADER, [
            'Authorization: Bearer ' . $this->apiKey,
            'Content-Type: application/json',
        ]);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $method);
        if ($data !== null) {
            curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
        }
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        if ($httpCode >= 400) {
            throw new Exception("API Error: HTTP $httpCode");
        }
        return json_decode($response, true);
    }

    public function listResources($params = []) {
        $query = http_build_query($params);
        $path = '/resources' . ($query ? '?' . $query : '');
        return $this->request('GET', $path);
    }

    public function createResource($data) {
        return $this->request('POST', '/resources', $data);
    }
}

$client = new GeminiClient(getenv('API_KEY') ?: 'YOUR_API_KEY');
$resources = $client->listResources(['limit' => 50]);
echo "Found " . count($resources['data'] ?? []) . " resources\n";
?>

Best Practices

  • Store your API key in an environment variable, never in source code
  • Implement retry logic with exponential backoff for 429 and 5xx errors
  • Set reasonable timeouts (10-30 seconds) for all API calls
  • Log request IDs from response headers for debugging
  • Cache responses where appropriate to reduce API calls

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