Functional Software Engineer

The role

You will design, develop, and maintain software using functional programming principles. You will work on backend systems, domain modelling, distributed systems, financial infrastructure, blockchain applications, or developer tooling.

What you will do

• Design, implement, test, and maintain reliable software using functional programming principles.
• Develop clear, composable, and maintainable solutions to complex engineering problems.
• Apply strong typing, domain modelling, and abstraction to improve software correctness and reliability.
• Collaborate with engineers, technical leads, and client stakeholders to understand requirements and deliver effective solutions.
• Contribute to the design and architecture of systems.
• Write automated tests and use appropriate techniques to validate system behaviour.
• Review code, share technical knowledge, and contribute to engineering standards.
• Investigate and resolve complex technical issues across existing systems.
• Communicate technical decisions clearly and explain trade-offs to stakeholders.
• Adapt to different client environments, codebases, and technical challenges.

Required qualifications

• 5+ years of professional experience developing and delivering production software.
• Strong understanding of software engineering fundamentals, including data structures, algorithms, testing, and software design.
• Experience with functional programming, either professionally or through substantial projects.
• Ability to reason about complex problems and translate requirements into well-structured software.
• Strong debugging and problem-solving skills.
• Commitment to code quality, correctness, and maintainability.
• Ability to communicate effectively and collaborate with other engineers.
• Willingness to learn new technologies and work across different technical environments.

Nice to have

• Experience with Haskell, Scala, OCaml, F#, Clojure, or another functional programming language.
• Familiarity with type systems, algebraic data types, pattern matching, and immutable data structures.
• Experience with strongly typed domain modelling and functional design patterns.
• Exposure to distributed systems, concurrent programming, or backend infrastructure.
• Experience in blockchain, financial infrastructure, capital markets, or other domains where correctness and reliability are particularly important.
• Familiarity with property-based testing and other techniques for validating complex software behaviour.
• Experience with Nix or reproducible development environments.
• Experience working in an engineering consultancy or collaborating directly with client teams.

About the company

Obsidian Systems is a software engineering consultancy that builds production systems for capital markets and other regulated industries. They are a remote-first, globally distributed team.