Feeny
Mistral

Research Engineer - Eval Platform at Mistral (Paris, France)

Mistral· Paris, France·

Role details

Employment
Full-Time

Mistral at a glance

A French AI lab building open and frontier-grade large language models, with the full developer and enterprise stack around them.

Mistral is a French AI lab that builds open and frontier-grade large language models and sells the full stack around them: developer tooling, an agent studio, consumer and enterprise apps like Le Chat and Vibe, custom model training, and its own GPU compute. Its edge is deployment control, with open weights, EU hosting, and self-hosting for regulated and sovereign buyers.

$3B+ raised · latest: Series C · 1.7B euros · Sept 2025 · backed by ASML, Nvidia, Andreessen Horowitz, DST Global

Job description

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.

The Role

Evaluation is how we decide which models, checkpoints and recipes ship. As a Research Engineer on the Eval Platform team, you will build the infrastructure every science team relies on to measure model quality, and make it reliable, reproducible and fast. You don't need to have designed benchmarks before. You do need to care about what a score means, and about when a difference between two runs is real.

What you will do

  • Build systems that keep eval results reproducible and comparable over time, as models, benchmarks and code evolve.
  • Run evaluations at scale across our GPU clusters, from model serving to scoring.
  • Make eval results easy to access, explore and trust, through APIs and dashboards that researchers use every day.
  • Catch broken or noisy evals before they mislead research decisions.
  • Support evaluation of agentic, multi-turn and tool-using models.
  • Work closely with researchers to turn new evaluation needs into robust, shared tooling.

What we're looking for

  • Master's or PhD in Computer Science, or equivalent experience.
  • 4+ years building production-grade software, ideally large-scale ML codebases or distributed systems.
  • Excellent Python and strong software-design instincts: testing, code review, CI/CD.
  • Experience running workloads on GPU clusters (Slurm, Kubernetes, Ray or similar).
  • Familiarity with LLM inference and evaluation.
  • A product mindset: researchers are your users.
  • Self-starter, low-ego, collaborative.

Nice to have

  • Experience building or maintaining evaluation harnesses or benchmarks.
  • Hands-on experience with inference engines such as vLLM or SGLang.
  • Experience with agentic or RL environments.
  • Statistics for experimentation: variance estimation, significance testing.
  • Open-source contributions to ML tooling.

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.

Privacy Policy Your privacy matters to us. You can learn more about how we handle your personal data in our Applicant Privacy Policy.

Why work at Mistral

  • Culture: Flat structure, high ownership, low ego, and a "builders, not order takers" mentality. The company values audacity, speed, rigor, and customer centricity.
  • Remote/Hybrid/Office: Based in Paris (15 rue des Halles); relocation support and visa sponsorship offered. Specific remote/hybrid policy not detailed, but global team suggests flexibility.
  • Notable perks and benefits (from careers page):
    • 20 weeks paid parental leave for all birthing parents.
    • 100% employer-sponsored medical, dental, and vision coverage for employees and dependents.
    • 6% 401k match (US) / 5% pension contribution (UK).
    • Childcare support (reserved daycare seats or financial assistance).
    • Meal allowances and transportation support.
    • Fitness and wellness subsidies.
    • Relocation and settling-in services.
    • Financial and career planning support.
  • Team composition: 900+ employees from 30+ nationalities; 50% female leaders.
  • Interview process: For science, product, and engineering roles: intro conversation → 2-5 technical exercises → 1-3 interviews (hiring manager + teammates) → values conversation → reference checks.

Application questions