Peek App

Cmd-Tab on macOS switches between apps, not windows. Three VS Code windows count as one thing — you land on whichever is on top and hunt for the rest. Cmd-` only cycles the current app, blind. Mission Control throws the whole desktop in the air when you just wanted the browser back.

Peek replaces Cmd-Tab with a small panel showing a thumbnail of every open window across all Spaces, ordered by most recently used. Tap-and-release flips to the previous window — the same flip-flop gesture as Cmd-Tab between two apps, but per window. Option-Tab shows only the current app's windows.

There are deliberately no settings. The shortcuts can't even be remapped. AltTab [1] is the mature, configurable version of this idea; Peek is for installing once and forgetting about.

Two implementation details that took the most digging: CGWindowList only guarantees front-to-back order when you query on-screen windows, so listing across Spaces needs a separate z-order query merged in. And mapping an accessibility window handle back to a CGWindowID requires the private _AXUIElementGetWindow — same approach AltTab and Rectangle use, there's no public API for it.

~500 lines of Swift, no dependencies, MIT. The download in the releases is signed and notarized.