Software Engineer, Backend (Warsaw)

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. 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. about our culture on https://mistral.ai/careers.

Role Summary

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’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 from mid - senior to staff level 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

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 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

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

About You

Degree in Computer Science, Software Engineering, or equivalent practical experience

Proficiency in Python or another backend language (JavaScript/TypeScript, C#, Golang). Engineers are assessed in their preferred language during a live coding session

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

Now, it would be ideal if you had experience with:

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

Hiring Process

Introduction call - 45 min

Live-coding interview - 45 min

Hiring Manager interview - 30 min

Deep Dive Interview (only for leads & staff engineers) - 60 min

Culture-fit discussion - 30 min

Reference checks

Our Culture

We're driven to build a strong company culture and are looking for individuals with solid alignment with the following:

Reason with rigor

Are you audacious enough?

Make our customers succeed

Ship early and accelerate

Leave your ego aside

Engineering blog

Our first Engineering blog post is live, you can check it out here !