Slots

Select the nested frame, then right-click and choose Convert to slot. You can also use the Convert to slot button in the right sidebar, or press Cmd Shift S on macOS or Ctrl Shift S on Windows.

For text layers, groups, instances or several objects, right-click and choose Wrap in new slot instead.

Alternatively, select the main component, choose Create property, pick Slot, and then assign it to a frame with Convert to slot.

On a component set, use multi-edit to select the similar layers across variants and add the slot property to all of them at once.

Name the property and adjust its settings.

Name and description of the property.

Minimum and maximum layers. These are guidance: exceeding a limit turns the label orange and shows a warning, a met limit shows a green check, and nothing is blocked.

Preferred instances, a curated list chosen with Select preferred instances. They do not restrict what can be inserted, but the Add instances filter defaults to Preferred when any are set.

Only allow preferred instances, which tells designers to use only that list.

Display empty slots by default. Otherwise an empty slot shows a pink box only on hover.

Fill items on counter-axis by default, which applies Fill container to added items on the axis opposite the slot’s flow direction.

Open the BookCard main component and add a vertical auto layout frame between the cover and the button.

Select it, press Cmd Shift S (Ctrl Shift S on Windows) and name the property "details".

In Edit property, set a maximum of four layers and choose the Rating and Tag components as preferred instances.

Publish or use the component, then drag an instance onto a screen. Select the slot and use Add instances, or drag layers in from the canvas or the Assets panel.

On the instance you may change the slot’s fill, stroke, opacity, effects, layer name and export settings. Position, auto layout flow and constraints stay locked to the main component.

To undo your changes, select the slot layer, open More actions and choose Reset slot. To empty it, choose Delete contents.

Audit the library: search for "Slot", and look for main components named Slot reused in other components, placeholder frames and instance swap placeholders.

Shared placeholder component: in each parent component detach (or delete) the nested placeholder, make sure a frame with the same layout and size exists, convert it to a slot, set name, description and optional preferred values, then test insertion, layout, constraints and resizing. Finally move the old placeholder away and hide it from publishing.

Variant-based placeholder: remove the nested builder instance and insert a frame, convert it, then deprecate the builder component set. This is effectively a rebuild: variant logic and existing slot swap bindings are lost, so instances do not update automatically.

Publish the library update, which needs a paid plan.