Engineering Team Lead, Sandbox
This is the employer's own posting, not a copy on a job board.
What we know
Is it still open?
Confirmed still open
Last checked 1d ago — checked against the employer's own applicant tracking system, which is the company answering directly.
We re-read the employer's own applicant tracking system and the posting was still there. That is the company answering directly.
How old is it?
Posted 8d ago
The date the source published, not the day we noticed it (2026-09-23). Last seen at its source 2h ago.
We have tracked this listing since 23 Sep 2026 (8 days). The employer's own board has carried it every time we have read it, most recently 2 hours ago.
Is it remote?
Marked remote on the employer's board
Their board carries a remote setting on this posting — a field they filled in, not wording we read. The location field names somewhere specific, which is usually where the team or the entity sits.
Who may apply?
Paris, Zurich, Madrid, Amsterdam, Warsaw, London, Berlin
The description states no restriction of its own. This is the source's own tag.
Pay not stated
Similar roles pay €70k–98.8k/yr
Middle 50% of 11 listings that do state pay — Engineering · all levels · France · EUR/year. This employer has published no salary; this is what comparable listings we hold disclose, never converted between currencies or periods. How this is calculated.
Skills named in the ad
Recognised terms only, from a fixed vocabulary — this is what CV matching compares against.
Carried by 1 source
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ashby employer's own board first seen 8d ago · last seen 2h ago
The listing
About Mistral
Mistral provides full-stack AI solutions: from frontier models to developer tools, applications, and compute. We partner with enterprises tackling the hardest problems across high-stakes industries like finance, manufacturing, defense, healthcare, and the public sector, co-creating customized AI systems that they can run on their terms.
We are a dynamic, collaborative team passionate about AI and its potential to transform society. Our diverse workforce thrives in competitive environments and is committed to driving innovation. Our teams are distributed between Europe, North America, Asia and the Middle East. We are creative, low-ego and team-spirited.
The team
Mistral is building a sovereign AI cloud for Europe. Our customers in finance, healthcare, and the public sector run frontier models on European-jurisdiction infrastructure, and the Cloud Platform team builds the systems that make that possible — compute orchestration, Kubernetes, bare metal, storage, networking, and the datacenter fleet that runs it all.
We run it all on our own metal, our own network, our own datacenters — which means when something breaks, the fix is ours to write.
European Compute Units let enterprises commit to multi-year capacity on that infrastructure, and we are scaling toward a gigawatt of compute across Europe by 2030. You will design and ship the layer every sovereign AI deployment depends on and shape the team building it.
The Role
This is a people-leadership role from day one. You will manage the team — hiring, coaching, performance, growth paths, honest feedback — while staying close to the code: roughly half your time in architecture decisions and the hardest technical problems the team faces, the other half leading your squad. If you are looking for a senior IC role, this is not it.
AI agents don't run in browsers. They run in sandboxes — and you will lead the team building ours.
We build secure, isolated, network-controlled environments with snapshotting primitives, designed for AI agents and reinforcement-learning workloads. An RL training run doesn't need one environment; it needs thousands, created and destroyed every second. An agent needs to be sandboxed from the world while still feeling fast enough to be useful. That tension — airtight isolation, at fleet scale, at low latency — is the product.
Your customers are the people building the next generation of AI software on our infrastructure; the primitives you ship become the runtime their agents live in.
What You Will Do
Build the isolation layer: microVMs or containers, namespaces, cgroups, seccomp, snapshot and restore.
Own the security boundary. Customers run code they didn't write and can't fully trust — your systems make that safe.
Scale to fleets: creation latency, density, and lifecycle management for thousands of concurrent environments.
Write Go alongside your team and own the architecture and the hardest implementation decisions.
Grow the engineers, not just the software — set the standard for ownership and coach people past their comfort zone.
Own people management for the team: hiring, performance, growth paths, and honest feedback.
Partner with Product Managers to turn frontier research needs into shippable primitives.
What We're Looking For
2+ years of real people leadership. You have managed engineers — hired, coached, given honest feedback, and grown them. Hands-on contribution matters here, but this role is judged on the team you build and lead, not just the code you write.
Deep Linux internals: namespaces, cgroups, seccomp, virtualization — ideally microVMs of the Firecracker class.
You have shipped production systems in Go. Not dabbled. Shipped.
You understand network isolation at the packet level — not just firewall rules.
Performance instincts: you know what a syscall costs, and you have the profiles to prove you've cared.
8+ years building backend or infrastructure systems.
You have partnered with product, design, and business teams to ship software that reached real users.
A low-ego, team-first mindset. We care less about your exact domain and more about whether you are the kind of technical force other engineers want to work alongside.
What We Offer
We offer a comprehensive benefits package designed to support your well-being, growth, and work-life balance. Benefits vary by country and may include healthcare coverage, parental leave, retirement plans, relocation support, wellness programs, meal and transportation allowances, and other location-specific perks.
For the most up-to-date details on benefits available in your location, please refer to our Benefits page.
Privacy Policy
Your privacy matters to us. You can learn more about how we handle your personal data in our Applicant Privacy Policy.