iOS app discovery service AppGratis announced a $13.5 million Series A round of funding today led by Iris Capital, with participation from Orange Publicis Fund.

AppGratis is an app that features one free app a day and sometimes an app that’s heavily discounted as well.

“I look at the market today and I see people throwing millions [of dollars] at building the most complex technologies around app discovery. We’re throwing a lot of money at building the simplest product you can find in the market today,” AppGratis founder and CEO Simon Dawlat told Inside Mobile Apps.

Since AppGratis’ launch in the U.S. last week, the app has already reached the one million new user mark, and reached as high as the No. 6 spot on the top free iPhone apps chart. Dawlat also claims that AppGratis can deliver between 500,000 to 700,000 installs for an app in a day.

“From all the approaches to app discovery, we’ve set out for the simplest one, which is featuring a great free app every day and giving this app a hell of a lot of exposure among our community of app shoppers,” Dawlat says.

One of the apps AppGratis featured, Etermax’s word game Word Crack, generated 701,556 downloads on Jan. 12, according to a tweet from the official Word Crack Twitter account.

AppGratis, which was founded in 2011, currently has more than seven million users worldwide and more than two million daily active users (DAUs). It’s available in more than 120 countries including Japan, Brazil and now the U.S.

Paris-based AppGratis, which currently has 40 employees, makes money through a cost per install (CPI) model with big brand apps and through a revenue share model with indie developers, who don’t necessarily have a big budget. When working with indies, AppGratis gets a cut from monetization methods in the indie developer’s app, such as advertising or in-app purchases.

The new funding AppGratis received will be used to scale the company globally, hire top talent, and build on their app’s self-learning technology which will recommend certain apps to users once it learns enough about a particular user’s downloading habits.

According to our traffic tracking service AppData, AppGratis is currently the No. 6 ranked app on the top free iPhone apps chart.