Engineering Manager, Sandbox

Mistral; Greater London; On-site; GBP 120,000 - 180,000; Full time

Benefits offered by this job

Healthcare coverage

Parental leave

Relocation support

Retirement plans

Wellness programs

Job summary

Mistral is building a sovereign AI cloud for Europe. We design secure, scalable infrastructure for frontier models, with a focus on isolation, performance, and reliability.

As a team lead, you will hire and mentor engineers, own architecture decisions, and ship primitives that empower AI agents at scale. You’ll work closely with product managers to turn research into deployable systems.

Qualifications

• 3+ years of people leadership, managing engineers, hiring, coaching, and giving honest feedback.
• 8+ years building backend or infrastructure systems.
• Shipped production systems in Go; not just dabbling.
• Deep Linux internals: namespaces, cgroups, seccomp, virtualization.
• Experience with network isolation at the packet level.
• Strong performance profiling and systems optimization skills.
• Partnered with product, design, and business teams to ship software to real users.

Responsibilities

• Build the isolation layer: microVMs or containers, namespaces, cgroups, seccomp, snapshot and restore.
• Own the security boundary to ensure customers run code safely.
• Scale to fleets: manage creation latency, density, and lifecycle for thousands of environments.
• Design and build architecture with your team and guide the hardest implementation decisions.
• Grow engineers and set a standard for ownership and feedback.
• 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.

Skills

People leadership

Backend architecture

Linux internals

Network isolation

Performance profiling

Go backend

Tools

Go

Firecracker

Kubernetes

Job description

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

Agents don't run in browsers. They run in sandboxes — and you will lead the team building ours.

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.

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.
• Design and build alongside your team, owning 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

• 3+ 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.

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