Pingit launched in February as a way to conduct financial transactions of up to £5,000 a day using iOS, Android and BlackBerry smartphones without having to share bank details.
The service was downloaded 400,000 times in its first eight weeks and reached number one in the financial apps section of Apple's iTunes in February.
Pingit was initially just available to banking giant Barclays's almost 12m current account customers, but the service has today expanded to all consumers, regardless of whether they bank with Barclays.
Barclays said that a number of new consumer and business features are planned for Pingit over the coming months, including joint account registrations.
The bank said that Pingit is proving popular with many small businesses and eBay users, as it offers a way to accept small payments instead of using cash, cards, cheques or online transfers, such as PayPal.
In response to strong customer demand, the service was also expanded to 16- and 17-year-olds with a current account at the end of February.
"Barclays Pingit is proving to be more popular than even we were expecting and from today the customers of all UK banks and building societies can also benefit," said Antony Jenkins, the chief executive of retail and business banking at Barclays.
"The ability to make simple payments to whoever they want, wherever they are, instantly and securely, is making many people's lives much easier.
"Barclays Pingit is potentially a revolution in banking but this is just the beginning. We are listening to customer feedback and monitoring the demand for additional functionality so there's a lot more to come over the next few months."
To promote Pingit, Barclays has produced a video on its Facebook page featuring 'The Boy', who is trying to sort out a pizza debt between two friends. Facebook users are able to send customised versions of the video to any friends who owe them money, encouraging them to settle the debt via Pingit.
Alongside mobile, users without a smartphone can register online to receive money with Pingit if they have a UK mobile phone number and a current account.
> Boku reveals Near Field Communications service