Founding Senior Engineer

This role is with one of Dex's trusted partner companies. We work closely with their teams to truly understand their culture, goals, and what they're looking for, so we can match you with the right opportunity and give you context about the role before you commit to a process.

If you're interested sign up to Dex to apply.

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The role

A stealth-mode AI company is building a truly proactive AI assistant. Unlike reactive tools, this one maintains a living model of your entire work history – emails, messages, meetings, documents – to anticipate needs and act on your behalf. The team is small: repeat founders with deep technical and research backgrounds from top-tier institutions and leading tech companies. They're solving a hard, fundamental problem in AI: building a persistent, intelligent agent that truly understands context.

This isn't a narrow, siloed role. You'll be a Founding Senior Engineer, spanning the entire stack. That means building the performant desktop application, the backend for live model ingestion, and the algorithmic layer in between. You'll work directly with AI researchers, owning the end-to-end delivery of core product features. The scope is yours to claim. You're joining a small team, hiring more than one into this role, so you'll define your impact.

The work

Design and build the desktop application (front and back end) for a proactive AI assistant.

Develop and maintain the backend systems that ingest and keep a live, persistent model of user data current.

Implement core algorithms that bridge the AI research layer and the user-facing product, enabling proactive actions.

Drive end-to-end feature development, from user requests and hypotheses to shipping robust, scalable products.

Collaborate closely with AI engineers, translating research insights into production-ready systems.

What You Bring

Something genuinely remarkable: a PhD or personally owning a hard technical project end-to-end. This must be your project, not a team effort.

5+ years building comparable systems, with a track record of solving hard problems in academic or industrial settings.

Strong proficiency in TypeScript, Python, Rust, or C++, with the ability to quickly pick up new languages (Rust is key here).

Experience owning the full engineering lifecycle: shipping robust, scalable products directly from user requests, ideally with a scientific approach to problem-solving.

Comfort with cloud infrastructure, SQL/NoSQL databases, and a self-organising, autonomous work style.

Willingness to work in person five days a week in Elephant and Castle, London.

Why apply through Dex

This is a rare, high-impact founding role at a stealth-mode AI company, not widely advertised. Dex helps you cut through the noise: get a direct introduction, skip cold applications, and receive a full brief before you even interview. We'll ensure your profile is seen by the right people for this role and others like it, giving you an edge in a competitive market.

If you're interested, sign up to Dex to apply - https://jobs.meetdex.ai/jobs/e72252c5-1977-41c5-8cf6-6a8747ec47f0

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