Applied AI, Use-case, Software Engineer (Harness)

About Mistral 

At Mistral AI, we believe in the power of AI to simplify tasks, save time, and enhance learning and creativity. Our technology is designed to integrate seamlessly into daily working life.

We democratize AI through high-performance, optimized, open-source and cutting-edge models, products and solutions. Our comprehensive AI platform is designed to meet enterprise needs, whether on-premises or in cloud environments. Our offerings include Vibe, the AI assistant for life and work.

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 France, USA, UK, Germany and Singapore. We are creative, low-ego and team-spirited.

Join us to be part of a pioneering company shaping the future of AI. Together, we can make a meaningful impact. See more about our culture on https://mistral.ai/careers.

Role summary

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

About you

• 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

Location & Remote

This role is primarily based at one of our European offices (Paris, France and London, UK). We will prioritize candidates who either reside there or are open to relocating. We strongly believe in the value of in-person collaboration to foster strong relationships and seamless communication within our team.

In certain specific situations, we will also consider remote candidates based in one of the countries listed in this job posting — currently France & UK. In that case, we ask all new hires to visit our local office:

•  for the first week of their onboarding (accommodation and travelling covered)

•  then at least 3 days per month

What we offer

💰 Competitive salary and equity

🧑‍⚕️ Health insurance

🚴 Transportation allowance

🥎 Sport allowance

🥕 Meal vouchers

💰 Private pension plan

🍼 Parental : Generous parental leave policy

🌎 Visa sponsorship

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