Boost PHP API Calls with Guzzle Async Requests: A Step‑by‑Step Guide

When integrating third‑party APIs, synchronous calls can become a bottleneck; using asynchronous requests allows the script to fire requests without waiting for each response, dramatically improving throughput.

Synchronous Request Example

<?php
declare(strict_types=1);
$url = 'http://127.0.0.1:8888/index/sync';
$timeOne = microtime(true);
foreach (range(1, 100) as $key) {
    $list[] = file_get_contents($url);
}
$timeTwo = microtime(true);
echo '[x] [system call duration] ' . ($timeTwo - $timeOne) . PHP_EOL;

The loop makes 100 sequential calls and takes about 37.23 seconds.

Concurrent Requests with Guzzle

Guzzle is a PHP HTTP client that simplifies sending requests and can be used for both synchronous and asynchronous operations. Supports building query strings, POST, file upload/download, cookies, JSON payloads, etc. Same API for sync and async calls. Implements PSR‑7 for request/response handling. Abstracts underlying transport, allowing non‑blocking event loops. Middleware system lets you customize client behavior.

Install Guzzle via Composer:

composer require guzzlehttp/guzzle

Async Request Pseudocode

<?php
declare(strict_types=1);
require_once __DIR__ . '/../vendor/autoload.php';
use GuzzleHttp\Client;
use GuzzleHttp\Promise;

$requestData = [
    'username' => '开源技术小栈',
    'age' => 24
];
$url = 'http://127.0.0.1:8888/index/sync';
$header = ['Authorization' => 'Bearer xxxxxxxxxx'];

$timeOne = microtime(true);
$client = new Client(['verify' => false]);
for ($i = 0; $i < 100; $i++) {
    $promises[$i] = $client->postAsync($url, ['headers' => $header, 'json' => $requestData]);
}
$responses = Promise\Utils::unwrap($promises);
foreach ($responses as $key => $response) {
    echo "【Response Status】 : " . $response->getStatusCode() . "
";
}
$timeTwo = microtime(true);
echo '[x] [system call duration] ' . ($timeTwo - $timeOne) . PHP_EOL;

Running the async version completes 100 requests in roughly 10.41 seconds, with each response returning status code 200.

For more details, refer to the official Guzzle documentation: https://docs.guzzlephp.org/en/stable/quickstart.html