Mobile payment app Square has now registered 40,000 merchants to use its Card Case software, double the number it had just four months ago.

The iOS and Android app allows users to pay for goods without the need of a bankcard or NFC chip.

Instead the app saves your card details and uses geo-fencing to recognise nearby merchants that accept Card Case – you can then open a tab to place an order and pay for your goods at the till just by saying your name.

Merchants can also upload their contact details, vouchers, photos and menus to the app.

Card Case is separate to Square’s mobile card reader, which is already used by more than 1m merchants.

An added benefit for retailers is that no money exchanges hands physically and there’s no need to pull out a credit card, making the process far quicker (providing you can actually find the right merchant you want to pay).

TechCrunch reports that Card Case users tend to tip more, and some businesses saw their revenue increase by nearly 25% when using the system.

But the main reason for Square’s popularity is convenience, and the relatively low cost for merchants since there’s no need to buy expensive card readers or sign up to a bank contract.

While NFC is often touted as the future it has failed to gain a real foothold, despite having the backing of the major credit card and mobile phone companies.

But there is certainly an appetite for mobile payments. Barclays’ money transfer app Pingit achieved 20,000 downloads in just two days when it launched last month.

The app allows users to send and receive funds just by entering a five-digit passcode.

Pingit was the first mobile payment app to be launched by a major UK bank and its success undoubtedly means its competitors will be scrambling to release their own versions in the near future.