Software Engineer (Golang), Sandbox

Academic Key; Paris; On-site; EUR 90,000 - 120,000; Full time

Benefits offered by this job

Healthcare coverage

Relocation support

Meal and transportation allowances

Job summary

Mistral.ai in Paris is seeking a Software Engineer (Golang) to join our Sandbox team. You will build isolation layers for AI agents, focusing on secure, scalable environments that run frontier models and RL workloads.

You will write Go, own the architecture decisions, and partner with product to translate research needs into shippable primitives, while maintaining a strong emphasis on performance and reliability.

Qualifications

• Shipped production Go services.
• Strong Linux internals and virtualization knowledge.
• Experience with secure, isolated environments.
• 5+ years in backend or infra roles.

Responsibilities

• Build the isolation layer with microVMs/containers.
• Own the security boundary of customer code.
• Scale to fleets with low-latency orchestration.
• Develop in Go and shape architecture.
• Collaborate with product to ship primitives.

Skills

Go

Backend systems

Linux knowledge

Security isolation

Collaboration

Tools

Firecracker

Kubernetes

Container tooling

Job description

Software Engineer (Golang), Sandbox

Mistral.ai · Paris

Abroad Paris Full Time Link validated

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.

THE ROLE

AI agents don't run in browsers. They run in sandboxes — and you will build 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 and own the architecture and the hardest implementation decisions.
• Partner with Product Managers to turn frontier research needs into shippable primitives.

WHAT WE'RE LOOKING FOR

• 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.
• 5+ 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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