Founding Senior Full-Stack Engineer at stealth-stage AI coordination startup

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Job Title

Founding Senior Full-Stack Engineer

Salary

Not Disclosed

Company Description

Stealth-stage AI coordination startup

Job Description

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.

Location

London, UK or San Francisco, USA

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.

• 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.

• 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.

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.

Next steps

Step 1. Visit the job listing.

Step 2. Click 'Talk to Jack', or go straight there: https://www.jackandjill.ai/jobs/founding-senior-full-stack-engineer-at-stealth-stage-ai-coordination-startup-7268dee2-2d70-457f-b394-e7e72858070b?utm_source=linkedin&utm_medium=job_post&utm_campaign=featured_role_7268dee2-2d70-457f-b394-e7e72858070b

Step 3. Talk to Jack so he can understand your experience and ambitions.

Step 4. Jack will make sure Jill (the AI agent working for the company) considers you for this role.

Step 5. If Jill thinks you're a great fit and her client wants to meet you, they will make the introduction.

Step 6. If not, Jack will find you excellent alternatives. All for free.

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.