A window manager for Mac OS: what to fix before installing one

Six things are open. A browser with twenty three tabs, a second browser window that exists only because one tab needed to be visible at the same time as another, a chat app, a terminal, a notes app, and a video call that is about to start. The window that needs attention is two layers down, and finding it takes a pass through Mission Control or three presses of Cmd+Tab. That is the moment most searches for a window manager on Mac OS begin.

The tools that come back from that search do one job well: they decide where a window sits and how large it is. Before paying for one, it is worth separating that job from the job the search was really about, because they are not the same, and only one of them is solved by geometry.

What macOS already does without any installation

Window tiling has been part of macOS since Sequoia 15 and is present in Tahoe 26 and macOS 27. Apple's own documentation lists four ways to trigger it: drag a window to a screen edge, hold Option while dragging, hover the pointer over the green button in the top left corner of a window, or use the Window menu in the menu bar and pick a layout under Move & Resize.

The keyboard shortcuts are the part people miss, because nothing in the interface advertises them. Fn+Control plus the left or right arrow sends the active window to that half of the desktop. Fn+Control+Shift plus the left arrow does something more useful: it puts the active window on the left half and a second window on the right half in one action. Fn+Control+F fills the desktop, Fn+Control+C centres the window, and Fn+Control+R returns it to the size it had before tiling. The four quarter layouts have no default shortcut and have to be reached through the green button or the menu.

Two caveats are worth knowing before deciding this is enough. Dragging a window to the top edge of the screen opens Mission Control rather than maximising, unless the setting called "Drag windows to top of screen to enter Mission Control" is turned off in Desktop & Dock settings. And Split View is a different feature from tiling, reached through the green button under Full Screen. It moves both windows into a new space, hides the menu bar until the pointer reaches the top of the screen, and puts a divider between them that can be dragged. Tiling keeps windows on the normal desktop. Split View takes them off it.

When you drag a window all the way through the top edge of the screen, Mission Control opens. If you don't want Mission Control to open when you do that, turn off "Drag windows to top of screen to enter Mission Control" in Desktop & Dock settings. Source: support.apple.com

The problem a window manager cannot solve

A window manager operates on windows. It has no view into what is inside them. If the daily working set is twenty web services living as tabs inside two browser windows, then perfect tiling produces two perfectly placed panes, and every switch between a mail thread and a project board is still a click on a tab strip that has run out of room for labels.

The same limit shows up in the application switcher. Cmd+Tab lists applications, not windows, so a browser holding fifteen services is one entry no matter how the windows are arranged. Cmd plus the grave accent key cycles windows within the active application, which helps, but only if the services are actually in separate windows rather than separate tabs.

Notifications follow the same rule. A badge on a browser icon says that one of many services wants attention. Working out which one means switching to the browser and scanning. The number of tabs a window manager can move is zero, which is why the first question is how many windows the working set deserves, not where they should sit.

A useful test takes about a minute. Count the windows currently open, then count the distinct services being used inside them. If those numbers are close, a window manager will help immediately. If the second number is three or four times the first, geometry is the wrong lever, and the honest next step is different.

The second half of the test is about repetition. Note how many times in an hour the same pair of things has to be placed side by side, such as a spreadsheet next to a chat thread, or a document next to the page it is summarising. A tool that snaps windows pays for itself when that pair is stable and recurs, because the layout becomes two keystrokes. It pays for very little when the pair changes every time, because choosing the layout takes as long as dragging the window did.

Three categories of tool, and what each one is for

The results that come back for this search mix three different designs. Grouping them makes the choice smaller.

Tool	Cost	Shape of control	Stated macOS requirement
Built-in tiling	Included	Edges, green button, Window menu, Fn+Control shortcuts	macOS Sequoia 15 and later
Rectangle	Free, open source	Keyboard shortcuts and snap areas, repeat to cycle sizes	macOS 10.15 or later, Intel and Apple silicon
Rectangle Pro	Paid, 10 day trial	Adds custom shortcuts for any size and position	macOS 10.15 or later
Magnet	USD 4.99, JPY 490	Drag to edges and corners, halves, quarters, thirds	macOS 13.0 or later
Moom	USD 15	Pop-up palette on the green button, saved layouts	macOS 10.13 or later
Amethyst	Free, open source	Automatic tiling in the style of xmonad	macOS 10.15 or later
AeroSpace	Free, open source	Tree based tiling with its own workspaces, i3 style	Published as a Homebrew cask

Snapping tools are the mainstream choice. Rectangle is free and open source, works on Intel and Apple silicon, and has a detail worth stealing even if it is never installed: pressing the same shortcut repeatedly cycles through sizes rather than requiring a different shortcut for each one. Magnet is sold through the Mac App Store, currently at version 3.0.7, and supports up to six external displays. A Rectangle Pro licence can be active on three devices at a time.

Layout savers solve a different problem. Moom stores arrangements of windows and restores them on command, which matters most on a laptop that gains and loses an external display several times a day. Its pop-up palette sits on the green button and accepts up to 61 separate actions.

One more axis separates these tools in practice: how they behave when the number of screens changes. The built-in tiling treats each display independently and has no memory of an arrangement, so reconnecting a monitor leaves windows wherever macOS decides to put them. Magnet states support for up to six external displays. Moom exists largely because of this case, since a saved layout can be recalled after every dock and undock instead of being rebuilt by hand. Anyone working from a laptop at a desk in the morning and on a train in the afternoon should weight this behaviour more heavily than the number of layout presets on offer.

Automatic tiling managers are the other end of the scale. Amethyst and AeroSpace do not wait to be told where a window goes. They maintain a layout and fit every new window into it. That removes the decision entirely, and in exchange it removes the option of leaving one window deliberately floating in the middle of the screen.

The setup cost that download pages leave out

All of these tools reach into windows that belong to other applications, and macOS requires explicit permission for that. Amethyst documents it plainly: the app has to be granted access under Privacy & Security, in the Accessibility list. That permission survives updates, but it is a prompt that has to be understood rather than clicked through, because it is the same permission a screen recorder would ask for.

Automatic tiling managers ask for more than permission. Amethyst recommends turning off "Automatically rearrange Spaces based on most recent use" in Mission Control settings, because otherwise spaces swap positions during the day and keyboard navigation between them stops being predictable. AeroSpace goes further and does not use macOS Spaces at all for its workspaces, emulating its own instead, which is what lets it switch without animation.

Then there is the question of System Integrity Protection. The yabai project documents that SIP can be partially disabled so that a scripting addition is injected into Dock.app, which unlocks window server control and additional features. The project's own documentation declines to recommend whether anyone should do that. AeroSpace takes the opposite position and states that it will never require disabling SIP. For a machine used for paid work, that single line is a reasonable filter: a window layout is not worth weakening the protection that stops unsigned code from modifying system applications.

There is also an ongoing cost that shows up a few weeks in rather than on day one. Every macOS release changes something about window behaviour, and tools that sit this close to the window server are the ones that break when it does. Free and open source projects publish their supported versions plainly, which is why the version requirements in the table above are the most practical column in it. Before upgrading macOS on a machine that depends on one of these tools, checking that the project has shipped a release for the new version costs a minute and avoids a week of odd behaviour.

When the count of windows is the actual problem

For a working set built out of web services rather than native applications, the alternative shape is one window per service. Mail in one window, chat in another, the project board in a third, each with its own icon, its own slot in Cmd+Tab and its own notification identity. At that point the built-in Fn+Control shortcuts become genuinely useful, because there is something distinct for them to move.

Browsers built around that idea exist for macOS, and they change the unit of organisation from the tab to the window. Grouping those windows by the task in progress rather than by which account they belong to is the idea behind Workspaces, and whether the services in daily use are covered at all is answered by the list of supported apps before anything gets installed.

The trade-offs deserve naming rather than hiding. A second browser is another application to keep updated and another place session cookies live. Extensions do not always follow. Windows that stay resident use more memory than tabs that have been discarded. Anyone whose working set is mostly native applications, such as a code editor, a terminal and a design tool, does not have this problem at all and should stop at a snapping tool.

What to change first

Spend one day on the built-in shortcuts before installing anything, because Fn+Control+Shift plus an arrow already does the two window layout that most of these tools are bought for. If the friction that remains is finding a service rather than placing a window, the lever is the number of windows, not their geometry, and a browser that gives each web app its own window is the thing to try, which is what SpaceDeck is built for.