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.