Lago, based in Paris, is an open-source billing platform operating on a B2B SaaS model with significant potential in the fintech sector. Backed by investors like FirstMark, Kima Ventures, and Y Combinator, Lago is well-positioned for impact. The platform's customizability allows businesses to tailor billing processes to their unique needs, unlike many rigid and expensive proprietary systems. By addressing common billing inefficiencies and offering adaptable solutions, Lago could differentiate itself in a competitive market, attracting a diverse clientele seeking improved and streamlined billing operations.