The inventory can be accessed by selecting the chest icon located in the bottom right corner of the game menu or by pressing Z. The map and customization menu can be accessed from the inventory by pressing Z or Shift.
There is a medium-sized side map, inventory, and basic cat information displayed when opening the inventory. The player's starting inventory is 24 slots. Inventory expansions can be bought at various shops, and upgraded to a maximum of 60 slots.
The inventory displays current items the player has. By using a controller, cursor, or WASD keys, the player can select an item. When selected, an item's description is displayed, and can be held in the player cat's mouth or used. Non-consumable items are held automatically. Items can be swapped by selecting an item and an empty tile or using E to select. Items can be sorted with R, and the inventory can be cycled through outside of the menu using R. If the player is selling items to a shopkeeper, they can select all items to sell using R.
Storage can be used to store any extra items the player has. There are four chests in the den storage room and two chests in the spare rooms. Each chest can hold up to 60 items. The player can buy storage and spare room upgrades from Molby by using the summoning bell.