How to sync subitems across boards with Mirror Item
Mirror Item Multiple Boards · Updated
Short answer
Turn on Add Subitems when you mirror the item, and its subitems appear on the other board and stay in sync. You can also mirror a single subitem on its own, as a subitem or as a full item.
Bring subitems along with the item
In the Mirror Item tab, switch on Add Subitems before clicking Add Item. The parent and child structure is kept, new subitems sync too, and columns with the same name and type stay in sync on every board.

Add a subitem as an item on another board
Open the subitem, click the Mirror Item Multiple Boards tab and mirror it to another board. It appears there as a full, top-level item, which suits a master or leadership board, and stays in sync with the original subitem.

Add an item as a subitem
Mirror the item to the other board first, then select it there with its checkbox and convert it to a subitem under the parent you want.
Tip: Subitems do not count toward your item limit. A parent item and all its subitems count as one.
For every subitem scenario with examples, see how to mirror subitems in monday.com.
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