Over the course of the past year, the major card brands have been working to open their networks to third-party software and smartphone app developers in a bid to tap an emerging market.

Visa Inc., MasterCard Inc. and American Express Co. plan to attract independent programmers who can create software to increase the payment networks' transaction volume, much as programmers increased the appeal — and revenue — of smartphone platforms like Apple Inc.'s iPhone and Google Inc.'s Android. Outside developers could also make these entrenched payments networks a better fit for the Web, where newer alternative payments systems have already grabbed a significant share.

"The old guard is just trying to catch up with the new guys, and it might be too late," said Avivah Litan, a vice president and distinguished analyst at Gartner Inc. "This is all about the battle for the future. This is just a sign of how threatened they are."

Each company, however, is well behind the front-runner, PayPal Inc. The eBay Inc. unit has enjoyed a head start on the payments networks, having launched its own open-development platform last year.

The PayPal platform allows online banking vendors to offer PayPal payments within their own systems. Fidelity National Information Services Inc. has linked PayPal to its bill-pay system and S1 Corp. incorporated PayPal transfers into its mobile banking software.

"It's like old news with the new payments," Litan said. "It's a big contrast between the old, established players and the new players. The new players are just that much more agile."

PayPal has predicted that $1 billion would pass through its platform by the end of this year. Naveed Anwar, PayPal's senior director of its developer network, said his company welcomes other players to the market.

"I don't worry about" MasterCard and its forthcoming open development network, he said. "It's actually good."

Whatever its rivals offer, PayPal can still claim credit for having "helped define how payments happen on the internet," Anwar said.

Visa has tried to leap ahead in mobile payments with its July acquisition of CyberSource Corp., which brought with it a ready-made platform, Authorize.Net, that has been supporting e-commerce for a decade. In October, Visa announced that it had poured an undisclosed amount of resources into the company to revamp its tools for developers.

And Authorize.Net will soon make more of its parent company's payment network features, such as the online shopping portal Rightcliq, available on its platform.

Amex owns the online card processor Revolution Money, though analysts say it has not yet tapped the full potential of that purchase.

MasterCard followed suit with its purchase of DataCash Group PLC in October, which observers said was the Purchase, N.Y., card brand's own effort to catch up.

MasterCard and Amex did not make executives available for interviews.

With each of these purchases, the networks have found themselves surrounded by obstacles, said Brian Riley, a senior research director at TowerGroup.

One challenge has been balancing the networks' focus on security with the need to open up their platforms, Riley said.

"Opening up … [a network] is really a paradigm shift," he said. "It is not as natural as it would be with a new company."