Founding Senior Engineer (up to £140k)

Dex; Greater London; On-site; GBP 110,000 - 150,000; Full time

Job summary

Dex partner company is seeking a Founding Senior Engineer to own the desktop app, backend, and algorithms for a proactive AI assistant. You’ll shape the system end to end, working with AI researchers in a small, high-calibre team.

This role emphasizes building rather than integrating and requires leadership across the full stack. You will work directly with researchers, translating cutting-edge ideas into robust product features while managing data ingestion and model maintenance.

Qualifications

• PhD or demonstrable ownership of a hard, end-to-end technical project.
• 5+ years building complex, comparable systems and solving hard problems.
• Strong in TypeScript, Python, Rust, or C++, with quick mastery of new languages.
• Experience owning the full engineering lifecycle: shipping robust products.
• Comfortable with cloud infrastructure and SQL/NoSQL databases; able to operate in ambiguous environments.
• Willingness to work in person in London five days a week.

Responsibilities

• Build and own the desktop application, front and back end.
• Develop core algorithms bridging the AI model and user actions.
• Design backend systems for continuous data ingestion and model maintenance.
• Collaborate with AI researchers to translate research into shippable features.
• Drive architectural decisions across the full stack from UI to data persistence.

Skills

End-to-end ownership

5+ years experience

TypeScript

Python

Rust

C++

Cloud infrastructure

SQL/NoSQL

Education

PhD in a relevant field

Tools

TypeScript

Python

Rust

C++

Job description

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.

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.

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