Research Engineer - Cybersecurity (RL Environments)

Mistral AI is hiring a Research Engineer - Cybersecurity (RL Environments) for a remote role open to applicants in France. Level rates it ; you can apply on Mistral AI.

Level's read on this job

On Level's scale, this cybersecurity role is Builds AI ●●●●: the job is building AI systems.
The posting lists this role as remote.
Tools and skills the posting cites include Kubernetes, Docker and reinforcement learning.
Level classifies it as a senior role.
Level lists 234 other open roles at Mistral AI.

AI in this role

Design RL environments and synthetic data pipelines for cybersecurity model training and evaluation.

KubernetesDocker

reinforcement-learningcybersecuritypythonsynthetic-data-generation

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

Cybersecurity is one of the areas where AI could do the most good — and one where the capability must be built with particular care. As a Research Engineer on this track, you'll push our models' capabilities in vulnerability discovery and remediation, security analysis, incident response, and across the offensive-to-defensive spectrum of cybersecurity, and it will be your job to develop that ability deliberately and safely.

The work sits at the meeting point of research and engineering: you'll devise new approaches and be the one to implement them. Concretely, that means designing and building RL environments that reproduce realistic security scenarios, pipelines that generate synthetic training instances at scale, and experiments and evaluations that show what our models can actually do. Your results feed directly into the production training runs that shape our frontier models, in close collaboration with Mistral's researchers, engineers, and security specialists.

Security specialists and ML engineers are both welcome here — what matters is that you can hold your own in both worlds, and are eager to go deeper on the one you know less.

What You Will Do

Design and implement RL environments simulating cybersecurity scenarios.
Build the pipelines and infrastructure that generate synthetic cybersecurity training instances at scale — thousands of scenarios, not one hand-crafted exercise.
Conduct experiments and evaluations of model capabilities on these environments, from quick prototypes to controlled benchmark runs.
Own the infrastructure behind the environments: containers, sandboxes, VMs, cloud deployments, and orchestration (Kubernetes), all managed as code.
Partner with researchers and security specialists across Mistral, distilling their domain expertise into reproducible environments and datasets.
Write clear, efficient code in Python and enforce strong software-design practices: testing, code review, CI/CD.

What We're Looking For

Hands-on expertise in offensive and/or defensive cybersecurity: vulnerability analysis, web/network/cloud security, secure coding practices, and SOC.
Strong software engineering skills: clean, reliable, well-tested code — not just exploit scripts.
Fluency in Python plus comfort reading lower-level languages (C/C++) for vulnerability analysis.
DevOps experience: Docker, Kubernetes, cloud deployments, sandboxed or simulated environments.
A pragmatic research-to-engineering mindset: ship a working first version, then refine and scale it.
Working knowledge of RL techniques and LLM training methodologies, or strong motivation to develop it.
Self-starter, low-ego, collaborative — comfortable working across research and engineering.

Nice-to-haves

CTF, cyber-range, or bug-bounty experience — as a player, challenge author, or platform builder.
A research background in cybersecurity, academic or industrial, or in another experimental discipline.
Prior experience building RL environments or large-scale ML training infrastructure.
Relevant open-source contributions and projects.

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.

How we rate this

Research Engineer - Cybersecurity (RL Environments) at Mistral AI rates 90 out of 100 for how much of the daily work is AI. That makes it Builds AI (AI Level 4 of 4). The level is about AI in the job, not seniority.

Classification

Builds AI. The job is building AI systems.

●●●● Builds AI80 to 100
●●●○ Works on AI60 to 79
●●○○ Uses AI40 to 59
●○○○ Little AI0 to 39

Levels come from how often the tools, models and workflows of the role are named in the posting itself. Read the description and count the AI tools, models and workflows it names.

Key facts

Research Engineer - Cybersecurity (RL Environments) is an open job at Mistral AI.
Level rates this role AI Level 4 of 4: Builds AI.
The role is based in Paris and is marked remote.
The job was posted on September 25, 2026.
Seniority: senior.
Applications are handled by Mistral AI. Apply on Mistral AI

Prepare for this job

Built from this posting and from similar jobs on Level.

Skills and AI tools this role asks for

Reinforcement learningCybersecurityPythonSynthetic Data GenerationKubernetesDocker

Also common in cybersecurity jobs at this level

Generative AI AI agents RAG Machine learning AWS Azure

Pay

Typical cybersecurity job: $161k

This posting doesn't list pay. Use the typical cybersecurity figure when pay comes up. See cybersecurity jobs

Questions you could be asked

Tell me about a project where reinforcement learning was part of your work. What did you do?
Tell me about a project where cybersecurity was part of your work. What did you do?
Tell me about a project where python was part of your work. What did you do?
Tell me about a project where synthetic data generation was part of your work. What did you do?
Walk me through how you've used Kubernetes in your day-to-day work.

Adapt your resume

List these exact terms on your resume: Reinforcement learning, Cybersecurity, Python, Synthetic Data Generation, and Kubernetes. An applicant tracking system matches the wording, not the idea.
Attach one line of real, concrete experience to at least one of them. A tool named with nothing behind it rarely survives a human read.
Lead with what you built, trained or shipped. This role is judged on the AI system itself, not the tools around it.

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