Software Engineer (OCaml) — Paris, France

LexiFi is a leading software provider in the financial derivatives and structured products market. Our solutions are used worldwide by investment banks, private banks, asset managers, insurance firms, and fintech companies. We empower users with tools to create, price, and manage complex financial products — and we also offer our technology as software libraries integrated by partners and service providers globally.

We’re growing our core development team at our Paris headquarters (8th arrondissement). You’ll help design and build frontend and backend features, infrastructure components, and internal tooling — almost entirely in OCaml, a language we actively contribute to. As LexiFi expands its cloud-hosted offerings, you’ll also collaborate on deployment and reliability topics alongside our DevOps engineers. You’ll join an international, collaborative environment that values engineering excellence — we invest heavily in R&D and code quality, making this a great place to craft beautiful, reliable software.

What You’ll Do

• Build and evolve core products — Implement new features across the stack (UI, APIs, services) in OCaml.
• Design reliable backend components — Develop services and libraries that power complex financial workflows.
• Raise the bar on code quality — Improve testing, performance, and developer experience.
• Collaborate with quantitative engineers — Partner with our math-finance team on models, pricing engines, and data pipelines.
• Work closely with client-facing teams — Shape solutions with sales, support, and partners; occasionally join client conversations.
• Support cloud-hosted projects — Contribute to deployment, instrumentation, and operational excellence.

What You Bring

• Strong software engineering experience (professional or significant open-source work).
• Solid foundations in algorithms, data structures, and software design.
• Collaborative mindset, clear communication, and a problem-solving approach.
• Bonus points for:
  • Exposure to OCaml or functional programming.
  • Exposure to cloud or DevOps practices.
  • Interest or experience in financial markets.
  • A degree in computer science, mathematics, or related fields.

Location & Work Environment

• This is a full-time role based in Paris (8th arrondissement) at LexiFi’s headquarters.
• Hybrid work model — up to 2 remote days per week, with flexibility in choosing which days.

Why Join LexiFi?

• Join a fintech company at the intersection of finance and software engineering.
• Work with a team that invests heavily in R&D and code quality.
• Build across a broad technical spectrum with direct impact on core products.
• Build products trusted by global leaders in finance and tech, across America, Asia and Europe.
• Be part of a collaborative, high-caliber engineering culture that values learning, initiative, and flexibility.

LexiFi and OCaml

• The first company to adopt OCaml (in 2001) — and we’ve since helped partners adopt it too.
• Active in the OCaml maintainers team, the Dune development team, and the broader OCaml OSS ecosystem — see our work.
• Founding member of the OCaml Consortium and the OCaml Software Foundation.
• Regular sponsor of OCaml-related conferences and community events.

Interested? Send your resume and a short motivation letter to careers@lexifi.com. We look forward to hearing from you!