written in pure OCaml. MLdonkey, a peer-to-peer file sharing application based on the EDonkey network. Ocsigen, an OCaml web framework. Opa, a free and open-source programming language for web development. pyre-check, a type checker for Python created at Facebook. Semgrep, a bug-finding tool supporting many programming languages. Tezos, a self-amending smart contract platform using XTZ as a native currency. Unison, a file synchronization program to synchronize files between two directories. The reference interpreter for WebAssembly, a low-level bytecode intended for execution inside web browsers. Xen Cloud Platform (XCP), a turnkey virtualization solution for the Xen hypervisor. Users Several dozen companies use OCaml to some degree. Notable examples include: Bloomberg L.P., which created BuckleScript, an OCaml compiler backend targeting JavaScript. Citrix Systems, which uses OCaml in XenServer (rebranded as Citrix Hypervisor during 2018). Facebook, which developed Flow, Hack, Infer, Pfff, and Reason in OCaml. Jane Street Capital, a proprietary trading firm, which adopted OCaml as its preferred language in its early days. References External links OCaml manual OCaml Package Manager Real World OCaml Articles with example code Articles with example OCaml code Cross-platform free software Extensible syntax programming languages Free compilers and interpreters Functional languages ML programming language family Object-oriented programming languages OCaml programming language family OCaml software Pattern matching programming languages Programming languages created in 1996 Statically typed programming languages