We build and ship a Linux distro that runs on Xen as its control domain (Dom0). This role is about developing and maintaining the public API server: https://xapi-project.github.io/. There is both a junior and a senior role. The majority of the control-plane is written in OCaml, with some Python scripts, and OCaml<->C bindings. The codebase is more than a decade old, and has >240K lines of OCaml code, most of which is open source. We have an automated test suite that exercises various OS and x86-64 CPU families every night. Vacation: 25 days/year + UK bank holidays. Salary depends on the position, with opportunities for advancement, and bonuses depending on individual and business unit performance. Private pension plan, and health insurance.