WASHINGTON – Three of the nation’s four largest banks are launching a system that lets customers transfer money from their checking accounts using only a mobile number or email address.

The banks say the service, called clearXchange, will make payments easier than traditional money transfers, which require a bank routing number and move through a system controlled by Federal Reserve banks.

The service is a joint venture between Bank of America Corp., JPMorgan Chase & Co. and Wells Fargo & Co. The banks expect to add other financial institutions, eventually creating an industry-wide utility for moving money.

ClearXchange is an attempt by the banks to retain fee-weary customers who have embraced alternatives such as prepaid debit cards and eBay Inc.’s PayPal service.

The clearXchange system will be available nationally to customers of the three banks. The banks noted that clearXchange is linked to existing accounts, so customers don’t have to sign up and provide new personal information as they would with PayPal.

“Customers will be able to send and receive money even more quickly and easily — with full confidence their funds are in a bank account without worrying about cash, checks or higher-cost services,” said Jack Stephenson, director of Mobile, eCommerce and Payments at JPMorgan.

The service is a direct threat to PayPal, which dominates the market for online electronic payments with nearly 100 million active users.

EBay said last month that PayPal processed $27.4 billion in payments during the first quarter, a 28 percent increase over the previous year. PayPal’s revenue was $992.3 million.