Helium is the classic open-source floating browser for macOS, built by Jaden Geller. It shipped translucent windows and click-through, and it worked well. Then it was archived on February 6, 2022, and never updated for modern macOS. TopShelf is the actively maintained alternative: pin any web app or one of six built-in mini apps as an always-on-top window, delivered through the Mac App Store on today's macOS.
If you want a free, open-source, minimal floating browser and you are comfortable building from source that has not been updated since 2022, Helium still works for what it does. Its translucent-window and click-through modes remain unmatched for the specific "make the pinned window fade into the background" use case.
For everyone else, anyone who wants an app that installs cleanly on today's macOS, gets security updates, ships through the Mac App Store, and adds native mini apps like a floating pomodoro or calculator, TopShelf is the modern actively maintained alternative.
| TopShelf | Helium | |
|---|---|---|
| Actively maintained | Yes (updated 2026) | Archived Feb 2022, read-only repo |
| Runs on current macOS | Yes | Community forks exist (e.g. HeliumLift) but no guaranteed support |
| Float a web app as a small window | Yes | Yes |
| Built-in mini apps (calculator, notes, to-do, pomodoro, color picker, password generator) | Six included | Not included |
| Quick-launch installed native Mac apps | Yes | No |
| Translucent window / click-through | No | Yes |
| Menu-bar utility | Yes, lives in the menu bar | Standalone Dock app |
| Distribution | Mac App Store + Gumroad | GitHub source (build yourself) or old binaries |
| Pricing | One-time purchase | Free (MIT license) |
You want something free and open source, you are comfortable building a Swift project from source on macOS, and the translucency + click-through combo is specifically what you need. Helium's transparent window that lets you click through to whatever is behind it is a unique feature TopShelf does not have.
You can also look at community forks like HeliumLift, which rewrote Helium in modern Swift, though maintenance there is also sporadic.
You want an app that installs from the Mac App Store, works on macOS today without a build step, ships security updates, and is under active development. That was the reason Helium died, the maintainer moved on and nothing replaced it inside its original scope.
You also want features Helium never had: six built-in mini apps (calculator, notes, to-do, pomodoro, color picker, password generator), a proper menu-bar utility model instead of a Dock app, and quick-launch for installed Mac apps.
Two Helium features TopShelf does not replicate today are per-window transparency and click-through. If you specifically need the pinned window to be see-through and for clicks to fall through to the app underneath it, Helium (or one of its forks) still does that job better. That is on our roadmap; it is not there yet.