NEW YORK -- Apple had an app-y holiday season.

The tech powerhouse said customers spent US$1.1 billion on apps and in-app purchases during the two weeks ended Jan. 3. New Year's Day was the biggest day ever for the store with $144 million in sales, with Christmas Day second.

Overall in 2015, shoppers spent $20 billion in the app store, which sells apps for the iPhone, iPad, Mac and the Apple Watch and Apple TV which were launched this year. Apple didn't report total billings for 2014.

The company launched the App Store in 2008. The store has more than 1.5 million apps for iPhone, iPad and iPod touch users in 155 countries. Apps are available in 24 categories, including games, social networking, photo & video, sports, health & fitness, travel and kids.