It is easy to picture Screenly as the dashboard you log into. For most people that is all it ever needs to be. But the dashboard is only a front-end on top of an API, and everything it shows you, every screen, playlist, and schedule, it gets by asking that API.
This is what it means to call Screenly headless. The platform is the API, and the dashboard is one client of it. Anything you can do by clicking, your own code can do by calling, because the dashboard holds no special access that your code does not.
The practical effect is that the dashboard becomes optional. A large operation can provision screens, publish content, and adjust schedules entirely from its own systems, and never open the dashboard at all.
It also makes the API the foundation the rest of this group stands on. The CLI wraps it, and the MCP server hands it to AI assistants. Different tool, same API underneath. That makes the API the most complete and direct way in: anything a higher-level tool can do, the API can do, because those tools are clients of it.
So Screenly is not a closed product with a single way in. It is an engine you can reach however suits you, and the next page is about what you do with that.