I don’t have any first hand experience with it, but Moltin’s a new-to-me API Only ecommerce service/start-up. API only meaning there’s no UI, just REST endpoints for you to call and perform the basic operations of any ecommerce system. If you only have shallow knowledge of other open source and commercial ecommerce software you might wonder how something that’s API only is competing with platforms that have a prebuilt UI and an API. If you’ve actually used those APIs you probably don’t wonder that.
It would be interesting to take one of their sample applications and reverse engineer a generic implementation of the REST API (for certain definitions of interesting), but I’ll leave that for someone younger.