{"id":482686,"url":"https://alion.io/job/wasmer-senior-operating-systems-hypervisor-engineer-2","title":"Senior Operating Systems / Hypervisor Engineer","company":{"id":858,"name":"Wasmer","domain":"wasmer.io","url":"https://alion.io/company/wasmer","size_band":"11-50","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Work at a Startup","truth_index":null},"role":"Industrial Engineering","role_family":"Industrial Engineering","seniority":"senior","employment_type":"full_time","work_mode":"remote","remote_scope":"stated_countries","remote_scope_basis":"board_field","remote_working_hours":{"label":"CET","utc_offset_min":1,"utc_offset_max":1},"hiring_geo_confidence":"structured","locations":["Madrid, Spain"],"countries":["ES"],"hiring_countries":["ES"],"hiring_countries_total":1,"salary":{"min":60000,"max":90000,"currency":"USD","period":"year","gross":null,"usd_annual":90000},"salary_estimate":null,"experience_years_min":5,"visa_sponsorship":false,"relocation_package":false,"has_equity":true,"technologies":[{"name":"KVM","optional":false},{"name":"Linux","optional":false},{"name":"PostgreSQL","optional":false},{"name":"Rust","optional":false},{"name":"Unix","optional":false},{"name":"WebAssembly","optional":false},{"name":"Xen","optional":false},{"name":"C++","optional":true},{"name":"GitHub","optional":true},{"name":"JavaScript","optional":true},{"name":"Node JS","optional":true},{"name":"Python","optional":true}],"status":"live","first_seen_at":"2026-09-06T17:37:56Z","employer_posted_date":"2026-10-12","last_verified_at":"2026-11-01T01:48:24Z","board_verified":true,"closed_at":null,"days_open":55,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":55},"description":"Company: Wasmer (https://wasmer.io)\nType: Full-time\nLocation: Remote (CET ± 2)\n---\nBuild an operating system that runs everywhere\nMost engineers spend their careers using operating systems. A few get to build one. This role is for the second group.\nAt Wasmer, we're building WASIX - an OS emulation layer that brings full POSIX semantics to WebAssembly: 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 WebAssembly spec in another, deciding how mmap should behave on a platform that was never designed to have one.\nIf that sentence made you lean in rather than close the tab, keep reading.\nWhat you'll work on\nWASIX 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.\n\nThe Wasmer runtime - the sandboxing, scheduling, and memory-management machinery that makes thousands of Wasm \"processes\" run safely and fast on a single host. Think hypervisor problems, at a different layer of the stack.\n\nMaking 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.\n\nOpen source - a good chunk of your work will ship publicly, in one of Wasmers open-source repositories\n\nYou're probably a fit if you\nHave 5+ years of systems-level engineering experience, with real-world work on Linux internals, hypervisors (KVM, Xen, Firecracker, etc.), or comparable low-level runtimes - not just as a user, but as someone who has debugged, extended, or built them.\nHave 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.\nHave proven Rust experience, are fluent C and comfortable diving into large, unfamiliar codebases.\nKnow POSIX deeply: processes, signals, sockets, file descriptors, memory management - the stuff most people only meet through man pages.\nThrive with high ownership: you can take a fuzzy problem (\"make signals work correctly under Wasm\") and drive it from design to shipped code.\nLive in the CET timezone ± 2.\nBonus points (nice, not required):\nPrior work with WebAssembly, WASI, Emscripten, or other compilation-target runtimes\nContributions to open-source infrastructure (kernels, runtimes, container tech, emulators)\nExperience with virtualization, sandboxing, or security-sensitive systems code\nBenefits\nCompetitive salary and stock options.\nGenerous vacation policy.\nFlexible and or remote work policies\nMonthly fitness stipend.\nMonthly stipend for open-source contributions.\nEconomic support for skills development, continuous learning, and attending conferences.\nWhy this role is different\nGreenfield OS work is rare. Greenfield OS work with real users is rarer. WASIX already runs real software for real developers - which means your design decisions get stress-tested immediately, not in five years.\nYou'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. And because we're open source at our core, the work you do here is yours to point at for the rest of your career.\nAbout Wasmer\nWasmer 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.\nOur mission is to make software universally available. We're an open-source-first company, and we believe the best infrastructure is built in public.\nHow to apply\nSend 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. Tell us what you'd want to build in WASIX first.\nWasmer is a remote-first company. We welcome applicants of all backgrounds - what matters here is what you build.","description_format":"text","description_chars":4205,"description_truncated":false,"requirements":{"experience_years_min":5,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":null,"security_clearance":false,"languages":[]},"benefits":["Continuous learning","Generous vacation","Stock options"],"hiring_locations":[{"name":"Spain","iso":"ES","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Virtualization & Containers","Developer Tools"],"lifecycle":[{"event":"open","at":"2026-09-06T17:37:56Z"}],"visa":[],"liveness":{"score":9,"band":"cold","label":"Long shot","p_open":1,"p_active":0.308,"p_room":0.28,"age_days":54,"expected_fill_days":7,"reasons":["conf:2","win:tail","crowd:"],"computed_at":"2026-10-31T05:58:55Z"},"pay":{"stated_usd_annual":90000,"is_top_pay":false},"html_url":"https://alion.io/job/wasmer-senior-operating-systems-hypervisor-engineer-2","json_url":"https://alion.io/job/wasmer-senior-operating-systems-hypervisor-engineer-2.json","meta":{"generated_at":"2026-11-01T02:54:46Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":4451,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-11-02T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":858},"rest":"https://alion.io/mcp/rest/get_company?id=858"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Fwasmer-senior-operating-systems-hypervisor-engineer-2"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Fwasmer-senior-operating-systems-hypervisor-engineer-2"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Fwasmer-senior-operating-systems-hypervisor-engineer-2"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/wasmer-senior-operating-systems-hypervisor-engineer-2\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Fwasmer-senior-operating-systems-hypervisor-engineer-2"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":482686}},{"tool":"search_jobs","arguments":{"company":"wasmer.io","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":482686},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. 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