Is delivery-app commission charged before or after discounts and VAT?

It depends on the app. Uber Eats UK charges on the discounted price, Deliveroo UAE on the undiscounted price. Dubai's guidelines say commission should be on the net value without discounts or VAT. Read your contract.

• Uber Eats UK: where an offer discounts an item, the fee is on the discounted price.
• Deliveroo UAE: you fund discounts, and the fee is worked out on the undiscounted price.
• Dubai guidelines: commission should be on net order value, excluding discounts and VAT.
• Check: ask the app how it works out the fee on a real order.