FAST vs Rectangle

The honest version

Rectangle is a snapper. FAST is a workspace manager that happens to snap. Both put a window in half the screen when you press a key, and both restore the previous size of the window you just moved. The difference is scope: Rectangle acts on the window under your cursor, one at a time. FAST holds a model of the whole arrangement — which is what makes it possible to name it, save it, bring it back on different displays, and roll all of it back in one step.

If Rectangle already fits your workflow, we would genuinely rather you kept it than bought something you use twice. It is free, MIT-licensed and actively maintained, and it covers more than snapping: custom edge and corner snap areas, repeated shortcuts that cycle sizes, portrait displays, URL actions, per-app ignore rules and JSON import/export.

There is also Rectangle Pro, a separate paid app with saved multi-app layouts, triggers on display connect and wake, app launching and title matching. If you are comparing against Pro rather than the free app, the honest difference is not the feature list — it is that Pro composes many independent concepts, while FAST has one: a Scene, with everything else defined in terms of it.

What FAST adds

Scenes: your whole workspace, named and restorable

A Scene captures display roles, layouts, divider weights, theme, matched app windows and stacks — the meaning of the arrangement rather than its pixel coordinates. Restore one and FAST re-matches windows that are already open, launches the apps that are missing, and maps everything onto the displays you have right now. Dock your MacBook at a different desk and the same Scene still lands correctly. How Scenes work.

Stacks instead of eviction

Drop a window on a tile that is already occupied and a snapper has to displace whatever was there. FAST stacks them: a numbered badge appears and ⌃⌥⇥ cycles through the stack. The window you were reading is behind the one you are writing in, not lost somewhere on another screen.

Undo for geometry

⌃⌥Z reverses the last geometry change — a snap, a layout switch, a Focus Mode toggle, an entire Scene restore. Screen sharing that rearranges your desktop stops being a small disaster.

Per-display layouts, including ultrawides

Every connected monitor keeps its own layout, backdrop and saved app assignments. A native 5120×1440 display automatically gets a dedicated five-tile 49″ Super Ultrawide layout instead of quarters designed for a 16:10 laptop screen. Ultrawide setup.

Automation that is part of the design

Shortcuts, Siri, a fast:// URL scheme and the bundled fastctl CLI all run the same typed actions as the keyboard and the mouse, so scripted placement behaves identically and stays undoable. CLI and URL scheme.

What Rectangle keeps

• It is free and open source (MIT). You can read the code and keep using it forever without paying anyone. FAST is €29 once for one Mac — a real difference, not a rounding error.
• It is smaller. Fewer concepts, less to learn, nothing to configure beyond shortcuts.
• It has a long track record and a large community answering questions.

Can you run both?

Technically yes — both use the public Accessibility API and neither requires disabling System Integrity Protection. In practice you will want to unbind overlapping shortcuts in one of them. Every FAST shortcut can be changed or removed in Settings, including all of the ⌃⌥ defaults.

Trying FAST costs nothing but attention: every purchase carries a 14-day money-back guarantee, one email, no forms.