I'm not aware of large standalone projects that depend solely on it. Multicore is backwards compatible with stock OCaml though and 4.12 ships with some stub Ato

I'm not aware of large standalone projects that depend solely on it. Multicore is backwards compatible with stock OCaml though and 4.12 ships with some stub Atomics (https://github.com/ocaml/ocaml/blob/4.12/stdlib/atomic.mli https://github.com/ocaml/ocaml/blob/4.12/stdlib/atomic.mli) which makes writing programs that can work on both easier. We also maintain some projects on top of Multicore that are pretty interesting: * Domainslib - channels and task queue that makes using parallelism via Domains much easier: https://github.com/ocaml-multicore/domainslib https://github.com/ocaml-multicore/domainslib * eioio - very much a work in progress but enables high performance direct-style IO with fibers and effects. Backs on to io_uring on Linux and is designed to also work with IOCP on Windows: https://github.com/ocaml-multicore/eioio https://github.com/ocaml-multicore/eioio