Each item has an Inventory number in Shop → Inventory. Stock goes down when a player completes a checkout with the item, and comes back if the booking is cancelled. Leave Inventory empty for unlimited stock.
Set the stock level
Go to Shop → Inventory.
Click ⋮ on the item and choose Edit.
Enter the number in Inventory, or leave it empty for no limit.
Click Save.
You can also use the − and + buttons on each item on Shop → Additional Items.
When stock goes down
Adding an item at checkout does not reserve it.
Stock is checked again when the player completes the checkout, and only reduced then.
If several players are checking out at the same time and stock runs out, the player sees a message such as "{item} is currently out of stock" or "Only {n} units of {item} available".
If a player buys several units, stock goes down by that number.
When stock comes back
When a booking is cancelled or automatically cancelled, the items' stock is returned.
With Refill inventory after session end time turned on (in Shop → Additional Items), stock comes back after the session ends. Use this for items players return, such as rental rackets. It only works when stock is not unlimited.
When you get new stock
Enter the new total. For example, if you have 25 tubes of balls and receive 100, change Inventory to 125.
Sales at reception
Items sold at your reception or till are not counted in Nettla. Reduce the stock in Nettla yourself, for example once a day using your till's sales figures.
Good to know
When an item is out of stock, it is hidden at checkout.
Claiming a rewards program item does not reduce stock.