On Monday afternoon, Mayor Marty Walsh bought a steaming hot cup of coffee at City Hall’s new cart. Boston Brewin Coffee Company is now offering 100 percent organic fair/direct trade coffee to customers from Monday through Friday, 8:30 a.m. to 4 p.m.

Jan. 5, marks the start of a four month pilot program between Boston Brewin and City Hall. Before the coffee cart is given a permanent home on the third floor mezzanine, the Mayor’s Office of New Urban Mechanics will examine the Boston Brewin’s effectiveness in activating the public space.

It’s purpose goes beyond caffeinating the Boston public to making City Hall a more welcoming building and acts as an exemplification of how the Walsh administration hopes to bolster its relationship with the city’s small businesses.

“There’s probably no better way than putting in a coffee shop,” said Mayor Walsh of making the mezzanine more inviting. “I would ask all of you to make sure that this is one of your regular stops for coffee.”

Boston Brewin also has a philanthropic model in place that serves both its employees and non-profit organizations.

Founder Tom Barnes noted Boston Brewin’s platform provides “a living wage to all of our employees. Everyone should be entitled to the opportunity to take care of their families and not be strained,” he said.

Coffee, lattes, mochas, espressos and teas all come courtesy of Boston Brewin’s partnership with Dean’s Beans. Boston Brewin also sources its baked goods from local vendors such as Haley House Bakery in Roxbury, C and C Bakers in East Boston, and Lyndell’s Bakery in Somerville.

He also mentioned that once Boston Brewin pays its bills, they take their profits and donate them to charitable organizations of the customers’ choice. With every purchase the buyer is able to vote for a group as part of its “Pay it 4ward” program.

Representing the program at the coffee cart’s opening were Zumix, Raising A Reader, Science Club for Girls, Boys & Girls Clubs, St. Francis House, Tenacity and Bikes Not Bombs.

The City Hall cart marks Boston Brewin’s third location. Their flagship is located at 45 Bromfield Street in Downtown Crossing and, in September 2014, it opened its East Boston branch at Maverick Square.