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. Dex is an AI recruiter agent that helps you run your job search. Tell Dex your stack, seniority, and what you want to build. We will manage your applications and surface other opportunities that are a fit. The role This team is building a truly proactive AI assistant. Not a chatbot, but an agent that maintains a living model of a user's entire work history — emails, messages, documents — to anticipate needs and act on their behalf. They are in private alpha with early customers, backed by leading investors, and founded by a small group of repeat founders with deep technical backgrounds. As a Founding Senior Engineer, you won't own a slice of the stack. You'll manage the whole thing: desktop application, backend, and algorithmic development, working directly with AI researchers. This is a chance to define your scope, not inherit it, building a complex system from first principles in a small, high-calibre team. It's for engineers who want to build, not just integrate. The work

• Build and own the desktop application, front and back end.
• Develop core algorithms that bridge the AI model and user actions.
• Design and implement the backend systems for continuous data ingestion and model maintenance.
• Work directly with AI engineers, translating research into robust, shippable product features.
• Drive architectural decisions across the entire stack, from user interface to data persistence. What You Bring
• A PhD or demonstrable personal ownership of a hard, end-to-end technical project.
• 5+ years building complex, comparable systems, solving genuinely hard problems.
• Strong in TypeScript, Python, Rust, or C++, with a proven ability to quickly master new languages.
• Experience owning the full engineering lifecycle: shipping robust products, working from user requests, and ideally running scientific processes.
• Comfortable with cloud infrastructure, SQL/NoSQL databases, and self-organising in an ambiguous environment.
• Willingness to work in person in London (Elephant and Castle) five days a week. Why apply through Dex This is a rare founding role at a company building genuinely novel AI. Opportunities like this are often oversubscribed or hard to find. Apply through Dex to get a full brief on the company and role, skip the cold application process, and explore other similar high-impact positions. If you're interested, sign up to Dex to apply - https://jobs.meetdex.ai/jobs/e72252c5-1977-41c5-8cf6-6a8747ec47f0 As part of the recruitment process at Dex, we process your personal data in accordance with our Privacy Notice for Job Applicants. This notice explains how and why your data is collected and used, and how you can contact us if you have any concerns.