Applied AI Software Engineer - Defense

Location: Paris 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. ABOUT THE ROLE Join Mistral AI’s Defense team to build software for defense institutions and industry. We are looking for an experienced software engineer with strong engineering fundamentals and a background in data engineering or transactional, analytical or distributed systems. You will help shape the architecture, write production code and own substantial software components, from design through deployment and operation. This role offers the scope and autonomy of a senior technical individual contributor in a small team. It is particularly suited to engineers operating at Senior or Staff level in demanding product engineering environments who want broad ownership and to stay deeply involved in implementation. WHAT YOU WILL DO - Design and build services for data ingestion, transformation, storage, querying and operational workflows. - Develop shared data models, APIs and SDKs that help engineers build applications on a consistent foundation. - Make authorization a core part of the architecture: define and enforce which users, applications and agents can access data or perform actions, with clear audit trails. - Solve problems involving data consistency, schema evolution, concurrency, performance and failure recovery across services and data systems. - Turn needs from our applied engineers and defense users into reusable software capabilities, making pragmatic choices about what to build and how to evolve them. - Own delivery end to end, including implementation, testing, observability, debugging and maintainability in demanding deployment environments. - Use AI coding tools and coding agents extensively to accelerate implementation, testing, refactoring and debugging. Help the team improve these workflows while maintaining a high engineering standard. WHAT WE ARE LOOKING FOR - Strong practical familiarity with AI coding tools and agentic engineering workflows. You use coding agents regularly, can break complex work into well-scoped tasks, provide effective context, review generated code and validate the result through tests and debugging. You remain accountable for the architecture, correctness, security and maintainability of what you ship. - A strong track record of building and operating production software, with substantial ownership of complex systems. - Experience in data engineering or in building transactional, analytical or distributed systems. You understand the trade-offs behind data models, storage, query execution and service boundaries. - Experience building products where access control, permissions and data governance are central to how the system works. Work on platforms such as Foundry, or systems with comparable requirements, is particularly relevant. - Broad software engineering skills and the ability to move between architecture, implementation and production debugging. You are comfortable working across unfamiliar parts of a codebase. - Strong proficiency in Python or another programming language, solid SQL skills and the ability to become productive quickly in a Python and TypeScript environment. - High autonomy and sound judgment: you can turn an ambiguous problem into a concrete plan, make technical decisions and deliver useful increments with limited supervision. - A collaborative approach to technical leadership through code, design discussions, reviews and mentoring, and a clear motivation to build software for defense institutions and industry. NICE TO HAVE - Experience building a data platform or developer product used by other engineering teams. - Experience with fine-grained authorization, multi-tenant architectures, data lineage or auditable operational workflows. - Experience with self-hosted software, restricted networks or other demanding deployment constraints. - Familiarity with LLM applications and their integration with data and 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 https://app.notion.com/p/mistralai/Benefits-at-Mistral-36e6ba59a7fe836b93dd01737fcc27ef?source=copy_link. PRIVACY POLICY Your privacy matters to us. You can learn more about how we handle your personal data in our Applicant Privacy Policy https://legal.mistral.ai/terms/applicant-privacy-policy.