Customers should think carefully about handing over personal data when ordering food and drink via their mobile phones, the UK's body overseeing data privacy suggests.
But the Information Commissioner's Office told the BBC that customers should be aware they had a choice over whether to share information.
"I think it's too easy to upload an app and straight away put your name, email address, payment details in, without actually understanding fully where that information may be shared and why it's being used," said Suzanne Gordon, director of data protection at the ICO.
"Ultimately this is your data, it's your personal information and you need to be confident when you're handing it over and the reasons why."
But they're popular with businesses too, because they speed up the ordering process and provide an additional way to interact with customers. Apps now handle millions of pounds worth of transactions every day.