Company: Wasmer () Type: Full-time Location: Remote (CET ± 2) --- Build an operating system that runs everywhereMost engineers spend their careers using operating systems. At Wasmer, we're building WASIX — an OS emulation layer that brings full POSIX semantics to Web Assembly: threads, processes, fork(), sockets, TTYs, signals, the works. It's the kind of problem where you're reading Linux kernel source in one tab and the Web Assembly spec in another, deciding how mmap should behave on a platform that was never designed to have one. What you'll work onWASIX itself — designing and implementing syscall semantics, process and threading models, virtual filesystems, and networking stacks on top of Web Assembly. Where Linux behavior and Wasm constraints collide, you'll be the one deciding what "correct" means.
The Wasmer runtime — the sandboxing, scheduling, and memory-management machinery that makes thousands of Wasm "processes" run safely and fast on a single host. Making real software just work — porting and running battle-tested Unix software (curl, bash, Postgre SQL-class programs)



unmodified on WASIX, and fixing everything that breaks along the way.
Open source - a good chunk of your work will ship publicly, in one of Wasmers open-source repositories You're probably a fit if youHave 5+ years of systems-level engineering experience, with real-world work on Linux internals, hypervisors (KVM, Xen, Firecracker, etc.), Have a genuine, self-driven interest in OS and hypervisor design — you have opinions about scheduler behavior, memory models, or syscall interfaces, and can defend them. Have proven Rust experience, are fluent C and comfortable diving into large, unfamiliar codebases. Know POSIX deeply: processes, signals, sockets, file descriptors, memory management — the stuff most people only meet through man pages. Thrive with high ownership : you can take a fuzzy problem ("make signals work correctly under Wasm") and drive it from design to shipped code.
Prior work wi

📌 Systems Engineer, Senior (Rúa)
🏢 WASMER
📍 Rúa