Founding Backend Engineer ($170,000 - $220,000 + 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 Backend Engineer Salary $170,000 - $220,000 + Equity Company Description River is a high-growth AI startup backed by the founders of Ramp, Kalshi, and JumpCloud. The team is building a sophisticated AI Account Executive: a voice AI agent that joins live B2B sales calls in real time to qualify prospects, demo products, and close deals autonomously. Job Description You will own the live-call pipeline for River's voice AI agent, ensuring sub-second response times during live customer interactions. As a founding backend engineer, you will manage infrastructure, scale the data layer, and build reliable browser automation to demo products in real-time. This is a high-ownership role defining the engineering foundations of autonomous sales. Location New York, USA Why this role is remarkable Join a founding team backed by iconic fintech and trading founders from Ramp, Kalshi, and JumpCloud to solve the hardest latency problems in voice AI.Work on a product that is already generating revenue and seeing demand that outpaces capacity, moving beyond simple lead generation to autonomous sales closing.Solve deep technical challenges involving real-time WebRTC pipelines, browser-use automation, and LLM orchestration where every millisecond counts in front of live buyers. What You Will Do Architect and maintain the live-call pipeline, ensuring low-latency stability and performance for voice AI agents during high-stakes sales conversations.Own the end-to-end infrastructure including deployments, scaling, observability, and incident response using technologies like Railway, Postgres, and Redis.Develop robust browser automation tools using Playwright and CDP to enable the AI to drive live product demos while speaking to prospects. The ideal candidate Brings 5+ years of experience building production backend systems with a proven track record of personally owning reliability, on-call rotations, and incident response.Possesses deep expertise in real-time, streaming, or low-latency systems such as WebRTC, voice protocols, or high-throughput trading platforms.Is a senior-level generalist comfortable with TypeScript and Node who uses AI agents to multiply their output and can ship without a formal spec. 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.