Product Engineer (Full-Stack)

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 Product Engineer (Full-Stack) Salary $90k-$140k + Equity Company Description River is a $2M pre-seed startup backed by the founders of Ramp, Kalshi, and JumpCloud building AI voice agents for B2B sales. Their technology conducts real-time qualification calls, demos products by live-controlling browsers, and manages automated follow-ups to close deals for sales teams. Job Description River is a $2M pre-seed startup backed by the founders of Ramp and Kalshi building AI voice agents for B2B sales. As a Product Engineer, you will build real-time services, LLM workflows, and browser-automation agents. Working directly with founders in New York, you'll ship daily to production for our first customers. Location New York, USA Why this role is remarkable Work at the bleeding edge of AI, building agents that don't just talk but navigate software live via browser automation.High-velocity environment with direct founder collaboration, shipping code to production almost every single day to serve active customers.Backed by elite founders from Ramp, Kalshi, and JumpCloud, offering significant equity and a trajectory-focused career path. What You Will Do Build and optimize the backend services behind live voice calls, including session state management, integrations, and data pipelines.Develop and refine the browser-use agent that performs live product demos and the automated prospect enrichment pipeline.Architect and implement LLM-powered workflows to handle complex sales qualification and real-time prospect interactions. The ideal candidate 1-3+ years of experience shipping production-grade software in TypeScript/Node, with a strong focus on backend systems and APIs.Proven track record of building functional applications using LLM APIs and a solid comfort level working across the React stack.Currently based in New York and thrives in a high-intensity, in-person office culture with a builder’s mindset. 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.