How to Use OpenAI API with PHP (Complete Guide, 2026)

PHP powers a large part of the web, but most AI tutorials focus on Python. This guide fills that gap: a complete OpenAI PHP tutorial with working code you can use in any PHP project or Laravel app.

Installation

composer require openai-php/client

Basic Setup

$client = OpenAI::client($_ENV['OPENAI_API_KEY']);

Chat Completions

$response = $client->chat()->create([
    'model' => 'gpt-4o',
    'messages' => [
        ['role' => 'user', 'content' => 'Explain what a PHP trait is.'],
    ],
    'max_tokens' => 256,
]);
echo $response->choices[0]->message->content;

Key Features

• Streaming — SSE responses with createStreamed()
• Function calling — expose PHP functions as tools
• Vision — pass images as URL or base64
• Laravel — register as singleton in service provider

Cost Tips

• Use gpt-4o-mini for simple tasks (17x cheaper than gpt-4o)
• Set max_tokens explicitly
• Cache responses in Redis for repeated prompts

Originally published at kalyna.pro