Leaf, which offers payment processing and customer analytics services, is entering a cut-throat market, but the start-up is giving back with a new Harvard Square program to help the homeless.

The company is offering free units of its LeafPresenter, a custom Android tablet, to area stores and letting customers choose how much they donate to a variety of non-profits.

Participating businesses include:

— Black Ink

— Brattle Square Florist,

— Concepts,

— Curious George

— Market in the Square

— Tistik

— The Tannery

Charities users can donate to are: Youth on Fire, Harvard Square Meals Program, On The Rise, Bread and Jams’ Self Advocacy Center, CASPAR, Spare Change and The Harvard Square Homeless Shelter.

“It’s combining cutting-edge technology with a business association that has a very strong, progressive community outlook to benefit a group of of organizations supporting people who are struggling in the area,” Ayala Livny, director of Youth on Fire, told the Globe’s Alyssa Edes. “In a way, I kind of think this would only ever happen in Harvard Square.”