Join a high-velocity founding team building the operating system for the agentic era. You will architect a real-time, multiplayer agent system that automates coordination work through proprietary semantic memory and symbolic control. This role bridges complex LLM workflows and high-performance front-end engineering to redefine how teams collaborate in the modern workplace.
Back to all jobs
Find a job with Jack
Founding Senior Full-Stack Engineer at stealth-stage AI coordination startup
We are looking for a Founding Senior Full-Stack Engineer to build the agentic layer of the modern workplace. Backed by top-tier VCs and led by a founding team of Oxford PhDs and industry veterans, this startup is moving beyond simple AI chatbots to create a proprietary system of proactive agents that handle coordination for entire organizations. If you are a TypeScript expert who wants to own the intersection of high-performance front-end craft and complex LLM infrastructure, this is a rare opportunity to join a high-traction team at the pre-seed stage and shape the future of work.
Overview
Role overview
Company
About the company
Stealth-stage AI coordination startup
Responsibilities
What you will do
- Own the end-to-end development of agentic systems, including multi-step LLM pipelines, structured outputs, and real-world agent negotiation loops.
- Architect and scale deep integrations with major productivity tools like Slack, Notion, and Linear to build a comprehensive world model.
- Optimize front-end performance to ensure the web and mobile applications feel instantaneous despite complex backend graph traversals and AI processes.
Candidate profile
Who this is a fit for
- Proven senior-level experience in TypeScript, React, and Node.js, with a track record of shipping complex production systems at scale.
- Deep hands-on expertise with LLM orchestration, including experience with evals, streaming, caching, and building reliable agentic workflows.
- High-agency mindset with 0-to-1 experience, capable of owning product features from initial specification through to production deployment in a high-trust environment.
What makes it remarkable
Why this role is remarkable
- You will be the first engineering hire, working directly with founders from top-tier academic and commercial backgrounds to define the technical foundation.
- The company is backed by top-tier global VCs and has already secured active procurement with major enterprise partners despite being in early stealth.
- You will build a new paradigm for work beyond simple chatbots, focusing on structured agent-to-agent negotiation and first-principles AI infrastructure.
Jack & Jill
How Jack & Jill work together
I get to know what you’re great at, then find roles you’d never find yourself.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.
I recruit from Jack’s network and make the intro when I spot a great match.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.
Meet Jack
Jack gets to know what you're great at and what you want next, then searches 15 million jobs daily and helps you discover roles at companies like this.
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.