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 with Web Assembly, WASI, Emscripten, or other compilation-target runtimes Contributions to open-source infrastructure (kernels, runtimes, container tech, emulators) Experience with virtualization, sandboxing, or security-sensitive systems code BenefitsCompetitive salary and stock options. Versátil and or remote work policies Monthly fitness stipend.

WASIX already runs real software for real developers — which means your design decisions get stress-tested immediately, not in five years. You'll join a small, senior, remote team where the interesting problems aren't handed down from an architecture committee — you'll find them, scope them, and solve them.

About

WasmerWasmer builds the software powering the next generation of computing platforms — local, cloud, and edge — on Web Assembly. Js unlocked server-side Java Script, we're unlocking server-side Web Assembly for every language: C/C++, Rust, Go, Python, and beyond. Our mission is to make software universally available.

We're an open-source-first company, and we believe the best infrastructure is built in public. How to applySend us your CV or Linked In — but honestly, we care more about your Git Hub, a project you're proud of, or a war story about the gnarliest low-level bug you've ever fixed. Wasmer is a remote-first company.

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