eBay said yesterday that it has bought Critical Path Software, a mobile-app developer that had already been working with the auction site for the past couple of years.

Helping to design several eBay mobile apps, Portland, Ore.-based Critical Path has partnered with eBay's mobile group to create eBay for the iPhone and eBay Classifieds. Critical Path and eBay also teamed up to develop StubHub, a ticket-buying app, and Shopping.com, a shopping comparison app.

The acquisition is part of eBay's move to focus even further on the growing mobile market. The auction site has also been busy scooping up other businesses this year. In June, eBay bought RedLaser, developer of an iPhone app that scans bar codes to compare products and prices. And earlier this month, it picked up Milo, a shopping service that tries to tie in online and offline shopping.

"We're very serious about innovating in mobile commerce, and this acquisition underscores our commitment to bringing the very best and brightest in the field to eBay," Mark Carges, chief technology officer and senior vice president of global products for eBay Marketplaces, said in a statement. "Integrating the Critical Path Software team into eBay will be a big win for mobile shoppers around the world."

The purchase price and other terms of the deal were not disclosed.