Mercury

Mercury banks more than 200,000 startups and small businesses, replacing the fee-laden incumbents that founders have grumbled about for decades. The product is unusual for a US fintech under the hood: the entire backend is written in Haskell on the Yesod and Persistent frameworks, an engineering choice that signals a high bar for type-safe, correct code in a domain where bugs move money. Two of the company's six values, Appreciate quality and Focus on the outcome, are how the team describes that bar in plain language.

Product engineering is organized into small, autonomous teams that the company describes as having a "startup within a startup" feel, with engineers self-organizing on small and medium projects and partnering directly with designers and product leaders. The benefits page reveals one detail most fintechs would not advertise: Mercury's unlimited vacation policy carries a mandatory minimum, an explicit counter to the unused-PTO problem that plagues most unlimited plans. A 6-week paid sabbatical kicks in at the 5-year mark.