The service was developed by the Payments Council and participating banks and building societies, with Bank of Scotland, Barclays, Cumberland Building Society, Danske Bank, Halifax, HSBC, Lloyds Bank, Santander and TSB involved from the launch in April 2014. More than 9 out of 10 current accounts in the UK support Paym after Clydesdale Bank, First Direct, Isle of Man Bank, NatWest, RBS International, The Royal Bank of Scotland, and Yorkshire Bank joined later in 2014. Metro Bank, Nationwide Building Society and Tesco Bank plan to join in 2015. The underlying network technology is provided by VocaLink, a member of the wider Single Euro Payments Area SEPA Payment Network.
The name "Paym" is stylised in the logo with a slight gap between "Pay" and "m", and is a play on words over "Pay 'em", a contraction of "Pay them", and "Pay M" alluding to "Pay Mobile".
The recipient must register in order to link their mobile phone number with their bank account. Those wishing to make a payment to a registered phone number can use their existing mobile banking or online banking service. Payments made through Paym take place at the same speeds as existing Faster Payments or LINK payment mechanisms.
The sender enters the recipient's phone number (or selects their number in their own phone's address book). The sender's bank then retrieves the account number and sort code associated with that phone number, and then sends the money using the Faster Payments Service. The sender is shown the recipient's name (in order to confirm that they are paying the right person) but not their account details.