Turbo Overlay turns any controller action into a modal- or drawer-friendly endpoint. A single stack container on the host page receives streamed overlays; the gem detects overlay requests, swaps in an overlay layout, exposes a request variant for view-level customization, and ships a custom turbo-stream action plus Stimulus controllers for opening, stacking, and closing overlays. Themes for Tailwind, Bootstrap 5, Bootstrap 3, and plain CSS are installable via generator.