Parallel processing component for Amp.

Fund package maintenance!

Installs: 3 445 711

Dependents: 41

Suggesters: 1

Security: 0

Stars: 537

Watchers: 22

Forks: 49

Open Issues: 34

v1.4.1 2021-10-25 19:16 UTC



Build Status Code Coverage Release License

amphp/parallel provides true parallel processing for PHP using multiple processes or native threads, without blocking and no extensions required.

To be as flexible as possible, this library comes with a collection of non-blocking concurrency tools that can be used independently as needed, as well as an "opinionated" worker API that allows you to assign units of work to a pool of worker threads or processes.


This package can be installed as a Composer dependency.

composer require amphp/parallel


The basic usage of this library is to submit blocking tasks to be executed by a worker pool in order to avoid blocking the main event loop.


require __DIR__ . '/../vendor/autoload.php';

use Amp\Parallel\Worker;
use Amp\Promise;

$urls = [

$promises = [];
foreach ($urls as $url) {
    $promises[$url] = Worker\enqueueCallable('file_get_contents', $url);

$responses = Promise\wait(Promise\all($promises));

foreach ($responses as $url => $response) {
    \printf("Read %d bytes from %s\n", \strlen($response), $url);

file_get_contents is just used as an example for a blocking function here. If you just want to fetch multiple HTTP resources concurrently, it's better to use amphp/http-client, our non-blocking HTTP client.

The functions you call must be predefined or autoloadable by Composer so they also exist in the worker processes. Instead of simple callables, you can also enqueue Task instances with Amp\Parallel\Worker\enqueue().


Documentation can be found on as well as in the ./docs directory.


amphp/parallel follows the semver semantic versioning specification like all other amphp packages.


If you discover any security related issues, please email instead of using the issue tracker.


The MIT License (MIT). Please see LICENSE for more information.

Development and Contributing

Want to hack on the source? A Vagrant box is provided with the repository to give a common development environment for running concurrent threads and processes, and comes with a bunch of handy tools and scripts for testing and experimentation.

Starting up and logging into the virtual machine is as simple as

vagrant up && vagrant ssh

Once inside the VM, you can install PHP extensions with Pickle, switch versions with newphp VERSION, and test for memory leaks with Valgrind.