Product Engineer
Build the agent. Ship weekly.
River · AI Voice Agents for B2B Sales · New York, NY
River builds AI voice agents that serve as full-cycle B2B SaaS sellers — qualifying prospects, answering complex questions, demoing products live in a browser, and following up until deals close, all available 24/7. Founded in 2024 by serial entrepreneurs who previously sold their first company, River just closed a $2M pre-seed backed by the founders of Ramp, Kalshi, and JumpCloud, alongside institutional money from Shuruk.
The company turned on revenue recently and scaled from $4,000 to $50,000 in weekly revenue within days of launch, with far more demand than the team can currently serve. River's core belief is that 60–80% of B2B software sales will be agent-led within the next few years, and the team is racing to build the definitive platform for that shift.
"You're the first engineer hire outside the founding team — 0.25% to 1% equity on the table, working directly with the founders with no layers, no PMs, and no tickets handed down."
Join River as the first engineering hire outside the founding team, building the AI voice agents that run live B2B sales calls — from backend services to browser-use demos — shipping to production weekly and working directly with the founders at a company that just turned on revenue and is scaling fast.
This is a chance to see your code running in real sales calls the same week you build it, at a company where the decisions you make in the next year will define the product for years to come.
- Build backend services and APIs behind live AI sales calls (session state, integrations, data pipelines)
- Develop the browser-use agent that navigates and demos real products live while the AI talks to prospects
- Work directly with design partners to shape the product — understanding their needs and building custom solutions that feed back into core product
- Build LLM-powered workflows: prompts, tool use, and agentic flows the agent follows during live demos
- Ship UI in Next.js/React where needed, watch real calls, and iterate fast
- 2–5 years of experience in full-stack engineering with a TypeScript/Node.js backend focus
- CS degree from a strong university (or equivalent demonstrated through exceptional shipped projects)
- Hands-on LLM application development (agents, tool use, prompt engineering)
- Active side projects or founder attempts with real users, revenue, or traction
- Shipped production software at a high-growth startup; or Big Tech paired with 0→1 work
- Strong TypeScript/JavaScript backend skills (Node.js, Next.js, APIs)
- Must be based in New York City or willing to move
- Customer-facing engineering: built directly with design partners or customers
- Experience in sales tech or GTM tooling
- Real-time systems — WebRTC, websockets, streaming
- Browser automation or computer-use agent experience
- Job hopper — pattern of short stints
- Strict management background, no interest in being an IC
- Only Big Tech experience maintaining stable systems (no 0-to-1 or startup exposure)
Initial Screen
30-minute conversation with Sam & Tarek, Co-Founders, to understand background, culture fit, and motivations.
Technical Interview
60-minute deep-dive with Sam, Co-Founder — includes a short live build-together exercise, plus questions on TypeScript/Node.js, backend architecture, and LLM application development.
Final Round (Optional)
30-minute in-person meeting with founders in New York — used when the team wants additional signal before extending an offer.