Who owns the customer data from delivery-app orders?

The app's terms decide, and they are tight. Zomato, Uber Eats and Lieferando let you use customer data only for that order. Customers who order on your own link are yours.

• Zomato: use customer data only to fulfil the order. No lists, no resale, no unsolicited marketing. Existing customers and direct opt-ins are exempt.
• Uber Eats US: data given for your own deliveries may be used only to fulfil that order and must not be kept afterwards.
• Lieferando: the platform keeps the IP rights in customer data it passes on. You may use it only to perform the contract.
• Uber Eats UK: the data you can access is lost when the agreement ends. You cannot opt out of Uber sharing aggregate data with partners.
• Your own link: customers who order there are yours.