Headless e-commerce has been growing lately. See the MACH Alliance [1] to find out about closed-source platforms in this space. One thing to note is that we can see more and more specialization, new categories, such as headless loyalty/PIM/search etc., appeared on the market. Earlier this year, I wrote a short article [2] explaining what problems these APIs try to solve (sorry for the clickbait title).
I think your criticism of the term is somewhat valid, in the end these are just back-ends with APIs :)
However, the point the platforms are trying to make is that their APIs have been written with the explicit purpose of building a frontend ontop of them later on.
A lot of the old-school platforms have some APIs as well, but they are meant to e.g. import products or export orders. They are not meant to implement a frontend on top of, because they have a frontend engine as part of their monolith, and many functions you need to write a proper frontend will not be available through their APIs.
So the term "headless" means "we have APIs, and they are designed for you to build a frontend on top of".
A “headless” computer system is just one without a local interface. There’s no monitor (“head”) plugged into it. There’s also no keyboard, mouse, touchscreen, or other local interface for controlling it.
MVC frameworks like Django, Rails, etc, are not headless by default, as they take care of all frontend rendering.
Headless = frontend and backend are fully separated; the "promise" was to have the backend be used on multiple projects. You would have a headless backend, then a web frontend project, an iOS one, an Android one, etc without having to rewrite any backend code.
I've been following https://www.shopware.com/en/ for a couple years. Awesome to see how they've grown in the space. Since it's written in PHP, I feel like it's a great replacement for Magento, especially as Adobe's catered more towards enterprise customers.
Nacelle is another. This is a very industry/salesy website, but they recommend a load of the most mature headless software platforms and integrators for stuff like ecomm and CMS:
Saleor.io is a good start. Consider Medusa and Vendure if you want to stay open-source.
If you are interested in SaaS, look at Elastic Path.
I see a lot of people recommending the MACH Alliance. That is a marketing organization where members pay in to push their products. Nothing wrong with MACH technology, but worth understanding what it is before going down that road.
