Software Engineer, Backend - Freelance

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 le Chat, 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 passionate and skilled software engineers to join our team. As a Backend Engineer, you’ll contribute to the development of the core systems powering our three main products, AI Studio, Le Chat & Mistral Code, shaping how users and developers interact with our AI platform at scale. You’ll work on building reliable, high-performance backend systems and APIs that serve millions of users and developers. Your work will directly impact the developer and user experience, making it more engaging, efficient, and intuitive. We welcome engineers at all levels from fresh graduates to senior and staff engineers and who are eager to learn, collaborate and ship impactful products.

What you will do

Depending on your skills and field of expertise, you will be involved in key components of our technology, including:

Backend Development

- Design, develop and maintain scalable, robust backend features and APIs using modern frameworks.

- Ensure high performance and reliability across our distributed systems.

- Contribute to systems powering authentication, billing, AI tooling, observability, connectors, and developer experience.

System Architecture

- Design and implement efficient, secure and scalable architectures that support our fast-growing products.

- Collaborate with infrastructure teams on deployment, monitoring, and performance optimization.

Code Quality

- Write clean, maintainable and well-documented code.

- Participate in code reviews and contribute to technical standards and best practices.

Cross-functional Collaboration

- Work closely with product managers, front-end engineers, designers and data/AI engineers to deliver end-to-end features.

- Partner with teams across AI Studio, Le Chat & Mistral Code to ensure consistent platform-wide experience.

Problem-Solving & Innovation

- Tackle complex engineering challenges, from distributed systems to AI product integration.

- Stay up-to-date with new technologies (e.g., AI/LLM integration, observability, or backend frameworks) and bring them into production when relevant.