# Product Engineer (Full-Stack)

Product Engineer (Full-Stack)

River · Full-time · New York, USA · 1–3+ years

About River

River builds AI voice agents for B2B SaaS sales teams. Our agent talks with prospects in real time: it qualifies them, answers the hard questions, demos the product by actually using it in a browser while it speaks, and follows up until the deal closes. A full AI seller, available 24/7.

We just closed a $2M pre-seed, backed by the founders of companies like Ramp, Kalshi, and JumpCloud.

About the role

You'll build River's product across the stack, with the backend as home base: the services behind live calls, the browser-use agent that runs the demos, and the data that makes each conversation personal.

You'll work directly with the founders, ship to production often, and see your work running in real sales calls the same week you build it. It's a high-ownership role for someone early in their career who wants a steep curve.

What you'll do

• Build the backend services and APIs behind live calls: session state, integrations, data pipelines
• Build the LLM-powered workflows: prompts, tool use, and the flows the agent follows during a live demo
• Work on our browser-use agent. River demos real products by controlling a browser live while it talks, and you'll teach it to navigate new products and complex UIs
• Build the enrichment pipeline that tells the agent who it's talking to before the call starts
• Ship UI where it's needed (Next.js, React), watch real calls, and iterate fast

Requirements

• 1–3+ years of experience, or exceptional projects. Either way, you've shipped real software that real people used
• Solid TypeScript and JavaScript, strongest on the backend (we use Next.js, Node, Postgres, Redis), comfortable in React
• You've built something real with LLM
• Product sense. You care how it feels to use, not only that it works
• High ownership. You find the problem, propose the fix, and ship it

Nice to have

• Browser use / computer use, or browser automation
• Voice, video, or anything real-time
• Scraping, enrichment, or data pipelines

Why River

• Small enough that everything you build matters, and you'll watch it run in real sales calls
• You work directly with the founders. No layers, no tickets handed down
• Try the product yourself at rivergtm.com/start