Senior Full-Stack Engineer - Stealth Company - Founding Engineer - Vertical AI

Antai Ventures is a Barcelona-based venture studio with presence across Southern Europe and Latam. Since 2012 we have co-founded 35+ companies including Glovo, Wallapop, Piper, PlatanoMelon, and Vitaance. Our ventures have raised more than $1.5B in funding, have generated more than $3B in shareholder value, and currently employ more than 3,000 people. At Antai, we partner up and invest in the best co-founders to build global companies willing to disrupt multi-billion dollar industries. In the last 12 years, we have gained experience in a variety of business models (E-Commerces/DNVBs, B2B SaaS, Marketplaces) operating in a wide range of industries including Edutech, Grocery, Healthtech, Fintech, Insurtech, Proptech, Autotech, among others. We are looking for a Senior Full-Stack Engineer to join the founding team of one of our portfolio companies — a B2B SaaS platform that helps service companies manage the complex, day-to-day operations of their distributed frontline workforce. Think scheduling, real-time coordination, coverage resolution, time tracking, and client communication — all powered by an AI agent that can make phone calls, contact workers, and take autonomous action to keep operations running smoothly. The vision is ambitious: build the operating system for an entire industry — starting with day-to-day operations, then expanding into deeper integrations across finance, HR, and everything else these companies need to run their business. AI isn't a feature we're bolting on — it's embedded from day one as a core capability that fundamentally changes how these companies operate. THE ROLE You’ll be one of the first engineers on a small, high-ownership team building a product from the ground up. This isn’t a role where you’ll be handed tickets — you’ll be researching customer problems, crafting detailed specs, designing solutions, writing code, and shipping features end-to-end. You’ll work directly with the founders and be expected to bring strong judgment about