Software Engineer, CyberSecurity at Mistral (Paris, France)
Mistral· Paris, France·
Role details
Mistral at a glance
A French AI lab building open and frontier-grade large language models, with the full developer and enterprise stack around them.
Mistral is a French AI lab that builds open and frontier-grade large language models and sells the full stack around them: developer tooling, an agent studio, consumer and enterprise apps like Le Chat and Vibe, custom model training, and its own GPU compute. Its edge is deployment control, with open weights, EU hosting, and self-hosting for regulated and sovereign buyers.
$3B+ raised · latest: Series C · 1.7B euros · Sept 2025 · backed by ASML, Nvidia, Andreessen Horowitz, DST Global
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 Role
We are seeking strong Software Engineers with cybersecurity experience to build and productionize our cybersecurity product offering. You will turn cutting-edge prototypes into robust, scalable services that power both our offensive and defensive security capabilities. Your work will directly enable Applied to deploy at client sites while giving Science the infrastructure to train against. You'll orchestrate red-team/blue-team agent loops, build on Mistral's corporate stack, and create the connectors, worker scaling, and SDKs that transform demos into production-grade services. This is a unique opportunity to shape how AI-powered cybersecurity operates at scale.
What You Will Do
Cyber Harness Productionization
- Build and productionize the cyber harness and service prototype, turning research into deployable solutions
- Orchestrate red-team / blue-team agent loops: find vuln → patch → redeploy → re-test
- Develop the context engineering that enables autonomous security workflows
- Create connectors, worker scaling mechanisms, SDKs, and packaging that make demos into services Mistral Stack Integration
- Build on Mistral's corporate stack: Workflows (temporal-style orchestrator) and Vibe
- Work with containers/Kubernetes to deploy and scale cyber capabilities
- Leverage Mistral Models to power agentic security workflows
- Migrate existing prototypes onto our production infrastructure Service Engineering
- Design and implement the engineering foundation that enables Applied to deploy at clients
- Create the infrastructure Science can train against for continuous improvement
- Ensure the cyber harness is robust, scalable, and maintainable
- Collaborate with security and engineering teams to integrate cyber capabilities
What We're Looking For
- Strong software engineer with hands-on experience building cybersecurity products or tooling
- Comfortable with agentic / LLM orchestration and context engineering
- Builder mindset with a track record of shipping production-quality code
- Experience with distributed systems and service architecture
- Strong problem-solving abilities and attention to detail
- Excellent communication skills and collaborative attitude It would be ideal if you also have:
- Red-teaming, offensive-tooling, or harness-building background
- Experience with orchestration internals (Temporal, Workflows, or similar)
- Prior experience building a "harness for X/Y use case in cybersecurity" or similar agent system
- Infrastructure knowledge: containers & Kubernetes to move fast
- Experience with AI/ML systems in security contexts
- Contributions to open-source security or orchestration tools
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.
Why work at Mistral
- Culture: Flat structure, high ownership, low ego, and a "builders, not order takers" mentality. The company values audacity, speed, rigor, and customer centricity.
- Remote/Hybrid/Office: Based in Paris (15 rue des Halles); relocation support and visa sponsorship offered. Specific remote/hybrid policy not detailed, but global team suggests flexibility.
- Notable perks and benefits (from careers page):
- 20 weeks paid parental leave for all birthing parents.
- 100% employer-sponsored medical, dental, and vision coverage for employees and dependents.
- 6% 401k match (US) / 5% pension contribution (UK).
- Childcare support (reserved daycare seats or financial assistance).
- Meal allowances and transportation support.
- Fitness and wellness subsidies.
- Relocation and settling-in services.
- Financial and career planning support.
- Team composition: 900+ employees from 30+ nationalities; 50% female leaders.
- Interview process: For science, product, and engineering roles: intro conversation → 2-5 technical exercises → 1-3 interviews (hiring manager + teammates) → values conversation → reference checks.