He's helped design the apps for a host of successful startups, including Gorillas and Arive.
He then helped build Zapp, an app for delivery services in the UK, before designing the layout for Gorillas' app.
He has since started his own business, Blossom, a design studio for apps, while he's also a designer-in-residence at the Swedish venture-capital firm Creandum, advising startups in the firm's portfolio on app design and recruitment.
The company already had a functioning app, but Haas said the company tasked him with "cleaning up" the design.
That's why the team also conducted interviews with the brands that sell their items via Arive's app, Haas said.