Founding Engineer ($170K–$220K + Equity) at River

This is a job that Jill, our AI Recruiter, is recruiting for on behalf of one of our customers. She will pick the best candidates from Jack's network. The next step is to speak to Jack. Job Title Founding Engineer Salary $170K–$220K + Equity Company Description River is a venture-backed startup building AI voice agents for B2B SaaS sales teams, supported by the founders of Ramp, Kalshi, and JumpCloud. Led by second-time founders with a previous exit, the team has already launched a sub-second latency product that is generating weekly compounding revenue for global customers. Job Description As a Founding Engineer at River, you will lead the development of real-time AI agents that handle live sales calls. You’ll own the entire pipeline—from WebRTC streaming to browser-use agents—while building the company’s engineering foundations. This is a high-ownership role for a technical entrepreneur ready to define a new category. Location New York, USA Why this role is remarkable True founding seat with meaningful equity (up to 2.5%) and direct influence over the product roadmap alongside experienced second-time founders.Elite backing from industry titans including the founders of Ramp, Kalshi, and JumpCloud, plus investment from Shorooq.Work on frontier technical challenges like sub-second latency voice, avatar rendering, and reliable autonomous browser-use agents in production. What You Will Do Architect and own the live-call pipeline, integrating real-time voice, video avatars, and browser streaming into a sub-second loop.Build and scale critical infrastructure, including deploys, observability, and cost-optimization for high-concurrency production environments.Establish core engineering foundations, including monitoring and testing frameworks, while shipping high-impact features across the full stack. The ideal candidate 5+ years of experience building production backend systems with a founder-grade track record as an ex-CTO, co-founder, or early breakout employee.Deep technical expertise in real-time streaming technologies such as WebRTC, WebSockets, or low-latency media servers.Degree from a tier-1 university and a high-ownership temperament, comfortable navigating the ambiguity of an early-stage, fast-moving environment. Who are Jack & Jill? Ok, I'll go first. I'm Jack, an AI that gets to know you on a quick call, learning what you're great at and what you want from your career. Then I help you land your dream job by finding unmissable opportunities as they come up, supporting you with applications, interview prep, and moral support. And I'm Jill, an AI Recruiter who talks to companies to understand who they're looking to hire. Then I recruit from Jack's network, making an introduction when I spot an excellent candidate. How does this work? Jack's an AI agent for job searching and career coaching. He works for you.Jill is the AI recruiter working for the company. She recruits from Jack's network.If it's a match and the company wants to meet you, they'll make the intro. In the meantime, if you'd like, Jack will send you excellent alternatives. We never post fake jobs This isn't a trick. This is an open role that Jill is currently recruiting for from Jack's network. Sometimes Jill's clients ask her to anonymize their jobs when she advertises them, which means she can't share all the details in the job description. We appreciate this can make them look a bit suspect, but there isn't much we can do about it. Give Jack a spin! You could land this role. If not, most people find him incredibly helpful with their job search, and we're giving his services away for free.