Droppy Playground
A free, separate app: the real notch, shelf and island, with only the media player inside, and a way to install droplets. Try one on the real surfaces before buying Droppy, or try the one you are building.
What it is
Droppy Playground is built from the same source as Droppy and draws the same surfaces with the same code: the notch, the expanded shelf, the Dynamic Island, mini HUDs and their cards, the lock screen chips and the menu bar. What it leaves out is everything else Droppy does. There is no file shelf, no clipboard, no Cloud, none of Droppy's own droplets except the media player, and no license.
It is its own app with its own bundle identifier and its own settings, so it installs beside Droppy without touching it, and it never updates itself into Droppy.
Installing a droplet
Open the Playground and its Store page appears. Drop a .droplet bundle onto the drop zone, or use Choose to pick one. That is the bundle droppykit build writes into .build/, or one somebody sent you.
The bundle is copied into the Playground's own droplet folder and put through exactly the five admission checks Droppy runs, so a droplet the Playground refuses is one Droppy would refuse too, for the same reason, which the Store row shows. A droplet the Playground accepts is switched on at once.
~/Library/Application Support/Droppy Playground/Droplets/<droplet-id>/<Name>.dropletWhy it loads what Droppy will not
droppykit build leaves the bundle unsigned. Droppy runs with library validation on and loads only droplets the Store review signed with Droppy's own identity, which is what "nothing loads unsigned" means. The Playground runs with library validation off and clears the quarantine flag from a bundle it installs, so the bundle you just built, or one somebody sent you, loads here. The five admission checks are the same in both apps.
Seeing both shapes
The Store page has a Display shape switch. Notch draws every surface the way a MacBook with a camera housing draws it: the wings, the cutout to keep clear of, the 32pt shoulders when the shell opens. Island draws every surface as the floating pill every other display gets. A droplet has to look right in both, and this is the fastest way to see whether it does, on a real screen.
Open the shelf from the button beside the switch, or hover the notch or island at the top of the screen, as in Droppy.
Playground or harness
Use the harness (droppykit run) for the edit-and-run loop: it renders every surface in both shapes at once, in Droppy's own metrics, without installing anything. Use the Playground when you want the droplet on the real surfaces, with the real host arbitrating, and when you want to hand a droplet to somebody who does not have Droppy. See The harness and Host support.
What it cannot tell you
The Playground is Droppy with things taken out, never Droppy with things added, so a surface that does not work here does not work in Droppy either, and one that does, does. What it cannot show is contention: with only the media player inside, your droplet's compact activity is rarely outranked here, while in Droppy a running timer or a recording takes the seat first. Handle the surfaceSuppressed and outranked seats anyway; the harness lets you see both.