Full-Stack Product Engineer ($90k-$140k + 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 Full-Stack Product Engineer Salary $90k-$140k + Equity Company Description River is a New York-based AI startup building autonomous voice agents for B2B sales teams, backed by the founders of Ramp, Kalshi, and JumpCloud. The company's AI seller qualifies leads, answers questions, and performs live product demos by navigating browsers in real time to drive deals to close 24/7. Job Description As a Full-Stack Product Engineer at River, you will build the core infrastructure powering live AI sales interactions. You will develop backend services for session state, engineer sophisticated LLM workflows, and create browser-automation agents for live demos. Joining a small founding team, you will ship to production daily in a high-intensity, in-person New York environment. Location New York, USA Why this role is remarkable Join a high-velocity founding team backed by elite investors and the founders of category-defining companies like Ramp and Kalshi.Work at the frontier of AI by building agents that perform complex, real-time product demonstrations in a live browser environment.Experience true product ownership with the autonomy to identify problems, build solutions, and ship features to production on a daily basis. What You Will Do Build the backend services and data pipelines behind live AI calls, managing session state and complex integrations using Node.js and Postgres.Engineer LLM-powered workflows using OpenAI and Anthropic APIs to handle sophisticated prompting, tool use, and automated demo flows.Develop and maintain the browser-use agent using Playwright to navigate live product environments seamlessly during customer interactions. The ideal candidate 1-3+ years of experience shipping production-grade software in TypeScript and Node.js with a strong focus on backend architecture and data.Proven track record of building and launching real products using LLM APIs, demonstrating an understanding of reliability and performance.High-ownership mindset with the ability to thrive in a scrappy, in-office startup culture without the need for detailed specifications. 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.