One of Commerce Guys’s major development initiatives is to make it easier to decouple Drupal Commerce. Our roadmap for these features is influenced directly by the work we’ve done to support large merchants who depend on both the scalability and flexibility of JavaScript-based front-ends to support high transaction volumes and multiple web and mobile front-ends. We spent most of 2018 researching, developing, and communicating ways to deliver headless Drupal Commerce. This included the development of the Commerce Cart API to power progressively decoupled Add to Cart forms and shopping cart interfaces before we turned our attention to supporting decoupled checkout interfaces. The Commerce Cart API project and the reference implementation in Commerce Cart Flyout demonstrate the results of that initial effort. See it in action on our demo store. Together they put Drupal Commerce on par with other major eCommerce software platforms and hopefully make it easier for Drupal agencies to sell Drupal Commerce as a competitive platform. That work wasn’t without its challenges. We reviewed the core RESTful Web Services module and JSON API / JSON RPC contributed modules but found unforeseen blockers in adopting either project completely for our work. In this session, Drupal Commerce co-maintainer Matt Glaman will present our comparative analysis of these API architectures, introduce what we developed to meet our needs, and explain how developers can use it to build and improve their stores.