Functional Software Engineer

Functional Software Engineer - Research & Quant Foundations (RQF)

Location: London (Onsite 4/5 days per week)

Experience: 4 years, varying levels of experience being considered.

Hires: 3+

Team: 7-8 engineers + manager.

We're working with a top-tier quantitative research and systematic trading firm operating one of the most advanced trading platforms in the world. Their systems are fully automated, globally distributed, and run at extreme scale - executing millions of trades per day. Platform resilience, uptime, and operational efficiency are mission critical.

As a Functional Software Engineer within the Research & Quant Foundations (RQF) group, you'll sit at the core of the platform, building systems that enable quant researchers to move faster across a vast compute estate. The focus is on abstracting complexity, improving developer experience, and ensuring large scale research workloads run smoothly and reliably.

This is a high bar engineering role for people who care deeply about functional design, correctness, and software quality.

• core scheduling platform written in F#, responsible for distributing very large workloads across massive compute farms
• Python and .NET SDKs that form the primary day to day interface used by researchers
• A TypeScript/React UI backed by an F# ASP.NET service, Postgres, and Kubernetes, providing real time visibility into workload execution
• Tooling and frameworks that enable researchers to build and deploy research platforms and express computations over streaming data
• Foundational systems designed for performance, safety, expressiveness, and long term maintainability

The codebase is approximately 75% F#, with the remaining 25% primarily Python and Rust. Day to day work includes high end, production grade Python, but the engineering culture is strongly rooted in functional programming principles.

• Strong interest and experience in functional programming
• 4+ years of software engineering experience in high bar environments
• Excellent programming ability with a deep focus on code quality and design
• Experience with one or more of: F#, Haskell, Rust, Lisp, Erlang, OCaml, Caml, or similar
• Professional Python experience beyond scripting or notebooks
• An engineer who genuinely cares about developer experience
• Exposure to compiler work or language tooling is a strong plus
• MSc or PhD in Computer Science (or equivalent depth of technical background) is highly desirable

This team hires exceptionally well and is scaling deliberately, with three new hires planned. If you're excited by functional programming, large scale distributed systems, and building foundational tooling that world class researchers rely on every day, this is a standout opportunity.