What it is

Sylius is a headless, open-source eCommerce platform built on top of PHP, the Symfony framework, and API Platform. It is distributed under the MIT license and has been developed for roughly fifteen years, with the current repository carrying about 8,500 stars, 2,100 forks, and 225 open issues. The project was originally created by Paweł Jędrzejewski and is maintained by a broad contributor base. It sits in the PHP and Symfony ecosystem, and it is positioned as a framework rather than a finished storefront: developers build the commerce application on top of it instead of configuring a hosted product.

The concrete problem it addresses is the gap between rigid hosted storefronts and the need for applications tailored to specific business requirements. Because the platform is headless, the commerce logic is exposed through a REST API, so the same backend can serve a web frontend, a mobile application, or any other client. Its stated development model is full-stack Behavior-Driven Development, using PHPUnit and Behat, which means the expected behavior of the shop is expressed in executable specifications rather than in documentation alone. Integrations and custom customer experiences are built against that API instead of being constrained by a fixed theme layer.

Key capabilities

• Headless architecture with a REST API for building custom frontends on any device.
• Built on Symfony and API Platform, so the application is extended through standard PHP framework conventions.
• Full-stack Behavior-Driven Development workflow, with PHPUnit and Behat as the testing tools.
• Composer-based installation, with a documented Docker installation path.
• A plugin ecosystem distributed through the Sylius Store and through Packagist packages marked as sylius-plugin.
• An optional commercial tier, Sylius Plus, which adds modular features such as OnePageCheckout and a B2B suite.
• Sylius Plus also covers multi-store management, partial order fulfillment, returns handling, a loyalty system, and multi-source inventory.

Who uses it and how

• Teams building a custom storefront who need commerce logic separated from presentation, using the REST API to serve web and mobile clients.
• Developers already working in Symfony who want to extend an eCommerce application through the framework rather than through a closed plugin system.
• Projects that require behavior specified and verified in tests, using Behat scenarios and PHPUnit suites as the working contract.
• Businesses that need B2B or multi-store behavior and adopt Sylius Plus modules rather than building those features from scratch.
• Organizations that want community support through Slack and Stack Overflow, or SLA-backed support and project assistance through a Sylius Plus license.

Getting started

The README directs users to install Sylius with Composer, with system requirements documented separately, and provides a Docker-based installation guide. A getting-started tutorial is available for choosing the platform and running a first project.

When to use it — and when not to

Sylius is a framework, so it is a reasonable fit when the requirement is a commerce backend shaped around a specific business, and a poor fit when the requirement is a store that works immediately after installation.