Software Engineer, Backend (Warsaw)

At Mistral AI, we believe in the power of AI to simplify tasks, save time, and enhance learning and creativity.

We are seeking passionate and skilled software engineers to join our Warsaw-based Context Engine team to build and enhance Mistral's agent harness, enabling us to deliver production-grade knowledge processing, directly impacting how users interact with our AI platform.

You will work on building reliable, high-performance backend systems and APIs that serve millions of users and developers.

Responsibilities

• Design, develop, and maintain scalable, robust backend features and APIs using modern frameworks.
• Ensure high performance and reliability across our distributed systems.
• Design and implement efficient, secure, and scalable architectures that support our fast-growing products.
• Collaborate with infrastructure teams on deployment, monitoring, and performance optimization.
• Write clean, maintainable, and well-documented code.
• Participate in code reviews and contribute to technical standards and best practices.
• Work closely with product managers, front-end engineers, designers, and data/AI engineers to deliver end-to-end features.
• Partner with teams across harness SDK team, the enterprise connectors (MCP platform) team, and search infrastructure (Vespa-based) while building and enhancing Mistral's agent harness (Vibe/Le Chat work mode) to enable models to navigate complex enterprise knowledge graphs.
• 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.

Requirements

• Degree in Computer Science, Software Engineering, or equivalent practical experience.
• Proficiency in Python or another backend language (JavaScript/TypeScript, C#, Golang).
• Strong understanding of backend fundamentals: APIs, databases, caching, messaging systems, and distributed architectures.
• Strong problem-solving abilities and attention to detail.
• Ownership mindset capable of shipping end-to-end features with minimal oversight.
• Excellent communication skills and collaborative attitude.
• Team-oriented, low-ego mindset and curiosity for learning.

Nice to Have

• Front-end development (Typescript, React, NextJS...) or full-stack exposure.
• Infrastructure management (Docker, CI/CD, Kubernetes, Helm, Terraform...).
• AI/ML engineering.
• Observability and monitoring tools (Prometheus, Grafana, Datadog…).
• UX and product-centric mindset.