Software Engineer (Golang), Sandbox

Mistral.ai; Paris; On-site; EUR 120,000 - 180,000; Full time

Benefits offered by this job

Healthcare coverage

Parental leave

Relocation support

Wellness programs

Meal and transportation allowances

Job summary

Mistral.ai is hiring for a backend/infrastructure role focused on building secure, high-performance isolation environments for AI workloads. You will design and implement the runtime primitives that agents run in, ensuring low latency and strong isolation across thousands of environments.

The role emphasizes Go development, deep Linux internals, and collaboration with product and design teams to ship scalable capabilities for frontier AI deployments.

Qualifications

• Deep Linux internals including namespaces, cgroups, seccomp and virtualization.
• Proven production experience shipping Go-based backend or infra systems.
• Understanding of network isolation and security in distributed environments.
• Strong focus on performance and syscall-aware profiling.
• Minimum 5+ years building backend or infra software.
• Collaborates with product, design and business teams to ship real-user software.
• Demonstrates a low-ego, team-first mindset.

Responsibilities

• Build the isolation layer using microVMs or containers, and manage namespaces and snapshots.
• Own the security boundary so customer code runs safely.
• Scale fleets with efficient creation latency and lifecycle management.
• Write Go and own architectural decisions for critical primitives.
• Partner with Product Managers to translate frontier research into shippable features.

Skills

Go programming

Linux internals

Networking isolation

Performance optimization

Backend/infrastructure development

Team collaboration

Security mindset

Tools

Kubernetes

Container tech

Firecracker microVMs

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.

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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