ML Operations Engineer

Proton was founded in 2014 by scientists from CERN on a simple truth: privacy is a fundamental human right. Since then, we’ve built the world’s largest encrypted email service (Proton Mail) and expanded into Proton VPN, Proton Drive, Proton Pass, and Proton Calendar—tools used by millions globally to protect their freedom, fight censorship, and keep their data safe. In some situations, Proton has literally helped save lives!

We are profitable, independent (no VC control), and selectively hire from the top ~1% of applicants. Our 500+ team members across 50+ countries come from leading organizations and elite academic backgrounds. We move fast, keep hierarchy light, and prioritize impact over optics. If you want to do meaningful work with exceptionally high-caliber people, this is it. Join us and do work you can truly be proud of. Check our open-source projects here!

We are looking for a MLOps / Infrastructure Engineer to join the MSA (Mail Security & Anti-abuse) team and support the operation and evolution of our machine learning anti-abuse systems.
MSA is a multidisciplinary group created in 2019 to tackle complex problems in mail delivery, spam prevention, abuse detection, and account security across the Proton ecosystem. Our systems combine human expertise and machine learning to make tens of millions of decisions daily, protecting users from spam, fraud, account compromise, and large-scale attacks.
Today, our focus areas include:

• Mail delivery and spam protection
• Abuse detection and account security
• Site reliability across Proton services
• New products such as Wallet and Lumo

Our systems have reduced spam misclassifications by over 60%, blocked millions of abusive signups, protected hundreds of thousands of users from account compromise, and mitigated hundreds of large-scale attacks.
To move fast with limited resources, we operate as autonomous teams owning systems end-to-end across infrastructure, backend, data, ML, and operations. In just a few years, we have grown from 2 to over 60 engineers and analysts across three continents, providing 24/7 protection to millions of users.
We are looking for humble, mission-driven engineers who enjoy learning, improving systems, and making a real-world impact.
This role is ideal for someone early in their career who wants to build strong foundations in infrastructure, automation, and production ML systems. You will work closely with experienced engineers to deploy, monitor, and maintain critical services that run 24/7 and protect millions of Proton users.

As an MLOps / Infrastructure Engineer, you will contribute to the reliable operation and continuous improvement of systems protecting millions of Proton users.

• →Assist in maintaining the operational stability of machine learning and anti-abuse systems running 24/7
• →Support deployment and maintenance of services and infrastructure under guidance from senior engineers
• →Help implement and improve logging, monitoring, and alerting for production systems
• →Participate in debugging and resolving production incidents with team support
• →Contribute to CI/CD pipelines and deployment automation workflows
• →Assist in deploying and maintaining containerized services using Docker and related tools
• →Support infrastructure automation efforts through scripting and configuration management
• →Document operational procedures and deployment processes
• →Gradually take ownership of infrastructure components and improvements as experience grows

• Experience with Linux system fundamentals (command line, systemd, troubleshooting)
• Proficiency in scripting languages (Bash and Python)
• Familiarity with Docker and containerization concepts
• Basic understanding of CI/CD pipelines and automated deployments
• Basic familiarity with databases such as MySQL or similar systems
• Experience with Git and collaborative development workflows
• Strong problem-solving mindset and ability to work and learn in a fast-paced global team
• Willingness to participate in on-call rotations after initial ramp-up
• Strong communication skills in English (written and verbal)

• Hands-on experience with Ansible, Puppet, or similar configuration management tools
• Familiarity with data processing and workflow orchestration tools (Airflow, Dask)
• Experience deploying services to production environments (personal projects count)
• Exposure to monitoring and observability tools (Prometheus, Grafana, ELK)
• Basic understanding of machine learning workflows or data pipelines
• Familiarity with Terraform, Kubernetes, or cloud infrastructure platforms

Even if you don’t meet all the requirements listed above, but feel you could still be a great fit, please still apply.

At Proton, we believe diversity drives innovation and strengthens our mission to provide privacy as a default for all. We are committed to fostering an inclusive environment where all individuals, regardless of race, ethnicity, gender, age, sexual orientation, physical ability, or socio-economic background, feel valued and empowered. We strive to create equal opportunities, promote open dialogue, and support continuous learning to ensure every voice is heard and respected.

If you need any extra support or reasonable adjustments during the hiring process, please let your talent partner know.

When you apply for a position, refer a candidate, or are considered for a role at Proton Technologies AG (Proton, we, us, or our), your information is stored in Greenhouse, in accordance with their Service Privacy Policy. This information is used to evaluate your suitability for the posted position. We also retain this information for consideration for future roles that you may apply for or that we believe may align with your background and skills.

If we no longer have a legitimate business need to process your information, we will either delete or anonymize it. Should you have any inquiries about how we use or manage your information, or if you wish to access, correct, or delete your data, please contact our privacy team at careers@proton.ch.

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To learn more about our privacy policy, please visit our privacy policy page.

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