@ Proximitty
Proximitty (YC W26) — AI operating system for commercial loans. Member of Technical Staff / first founding engineer. $150K–$220K, 1.5%–3.00% equity, San Francisco, CA (in-person, ~6 days/week, South Park). US citizen/visa only. Skills: TypeScript, Next.js, Mastra, Postgres, AWS, Inngest, Distributed Systems.
Our mission: Commercial credit is a $3+ trillion market in the US — and almost none of it has been automated. We're building autonomous lending agents — the infrastructure for how commercial credit gets issued. Proximitty builds autonomous commercial lending teams for the largest banks and fintechs in the US. Backed by Y Combinator, CRV, Cohen Circle, and Uphonest, with angels leading teams at Stripe and OpenAI. On track to hit 7-fig ARR by end of year.
Founders: Wye Yew (CEO) advised banks at McKinsey on commercial lending and credit risk and previously led Growth at Taptap Send ($75M -> $200M ARR in 12 months); first Malaysian to place Top 3 in the World Mathematics Championships in 2018. Zi (CTO) built the world's first MCP gateway at ACI.dev (4k+ GitHub stars in 3 weeks), and previously led Bloomberg's core security infrastructure (300K+ terminals); received the National Scholarship of China.
As our first founding engineer, you'll work directly with the founders on frontier applied-AI problems: long-horizon reasoning over years of complex financial data, reliable computer-use agents in brittle legacy systems, and evaluation infrastructure for high-stakes decisions. You will build core infrastructure for one of the smartest lending systems ever shipped; own the product end to end — architecture, agents, evals, UI/UX; deploy with customers — fly to banks, sit with credit officers; create self-evolving agents and a software factory that hill-climbs on evals.
We're looking for: ex-founders and people with high agency and ownership; raw intelligence over experience; competitive programming / quant / Math Olympiad backgrounds; open-source contributors; people who've worked at fast-growing startups and can keep up with our pace. You deeply understand the security, reliability, and auditability of shipping AI agents for banks, fintechs, and regulated financial institutions. You're constantly up to date with frontier agentic architecture, techniques, harnesses, and self-evolving infrastructure. Strong desire to own a product end to end: building it, deploying it, talking to customers, selling it. Can hold your own with a 60-year-old banker. Comfortable with change. Pragmatism over perfection.
Tech stack: TypeScript, Next.js, Mastra, Postgres, AWS, Inngest. In-person at our offices in San Francisco; expect to fly ~2x a month to deploy with clients.
Interview: 30-min conversation with both cofounders; a 3-day paid work trial (flights + accommodation included); offer.