Company: Type: Full-time
Location: Remote (CET ± 2)
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It's the kind of problem where you're reading Linux kernel source in one tab and the WebAssembly spec in another, deciding how mmap should behave on a platform that was never designed to have one.
WASIX itself — designing and implementing syscall semantics, process and threading models, virtual filesystems, and networking stacks on top of WebAssembly. 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, PostgreSQL-class programs) unmodified on WASIX, and fixing everything that breaks along the way.
Have 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.
Contributions to open-source infrastructure (kernels, runtimes, container tech, emulators)
Experience with virtualization, sandboxing, or security-sensitive systems code

Adaptable and or remote work policies
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 Wasmer Wasmer builds the software powering the next generation of computing platforms — local, cloud, and edge — on WebAssembly. Just as Node.js unlocked server-side JavaScript, we're unlocking server-side WebAssembly 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 apply Send us your CV or LinkedIn — but honestly, we care more about your GitHub, 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 (Castro Urdiales)
🏢 WASMER
📍 Castro Urdiales