Applied AI, Use-case, Software Engineer Harness

Applied AI, Use-case, Software Engineer Harness Overview

Mistral AI is hiring a Software Engineer focused on applied AI and cybersecurity use cases to help turn early-stage prototypes into production-ready services. The work sits within the Solutions organization and is centered on building the technical foundation for Mistral’s cyber harness so that the company can deliver security capabilities to customers and also provide infrastructure that internal research teams can use for training and iteration. This is a hands-on engineering role for someone who enjoys taking ambitious prototypes, hardening them, and scaling them into reliable systems.

What you will work on

• Take the cyber harness and its service prototype from research output to a deployable, production-grade system.
• Build the agent loops that support offensive and defensive security workflows, including the cycle of discovering a vulnerability, applying a fix, redeploying, and validating the result again.
• Design the context-engineering layer that allows autonomous security workflows to operate effectively.
• Create the supporting components that make demos usable as real services, including connectors, worker-scaling mechanisms, SDKs, and packaging.
• Develop on Mistral’s internal stack, including its workflow orchestration platform and Vibe, and adapt existing prototypes so they run on production infrastructure.
• Use containers and Kubernetes to deploy and scale cybersecurity capabilities.
• Apply Mistral models within agentic security workflows.
• Build the engineering base that enables the Applied team to deploy solutions at client sites.
• Provide the infrastructure that the Science team can train against for ongoing improvement.
• Work with security and engineering partners to integrate cyber capabilities into the wider platform.
• Make sure the harness is robust, scalable, and maintainable over time.

What the company is looking for

• A strong software engineer with direct experience building cybersecurity products or security tooling.
• Comfort working with agent-based systems, LLM orchestration, and context engineering.
• A builder mindset and a track record of shipping code that is ready for production.
• Experience with distributed systems and service architecture.
• Strong problem-solving ability and a careful eye for detail.
• Clear communication skills and a collaborative working style.
• Bonus experience in red teaming, offensive tooling, or harness development.
• Familiarity with orchestration internals such as Temporal, Workflows, or comparable systems.
• Prior experience building a harness or similar agent system for a cybersecurity use case.
• Infrastructure experience with containers and Kubernetes.
• Experience using AI or machine learning systems in security-related environments.
• Open-source contributions in security or orchestration tooling.

Team and working setup

The role is based primarily in Mistral AI’s European offices in Paris or London. The company prefers candidates who already live in one of those locations or who are open to relocating there. Mistral places a strong emphasis on in-person collaboration and believes it helps build strong relationships and smoother communication across the team.

In some specific situations, remote candidates may be considered, but only if they are located in France or the UK. For those remote arrangements, new hires are expected to travel to the local office for the first week of onboarding, with accommodation and travel covered, and then attend the office at least three days each month.

The team is distributed across France, the USA, the UK, Germany, and Singapore, and is described as creative, low-ego, and highly collaborative. The company positions itself as a dynamic group working to democratize AI through high-performance, open-source, and cutting-edge models, products, and solutions.

What is offered

• Competitive salary and equity.
• Health insurance.
• Transportation allowance.
• Sports allowance.
• Meal vouchers.
• Private pension plan.
• Generous parental leave policy.
• Visa sponsorship.

How to apply

Submit an application through the job posting’s application link. By applying, you agree to the company’s Applicant Privacy Policy.

Degree Requirement: Not Specified

Visa Sponsorship Promising