Proton is hiring a Senior Machine Learning Engineer (Security)

Responsibilities

• Design, develop, and deploy machine learning models to enhance security detection, anomaly identification, and incident response.
• Integrate ML outputs into the SOC workflow to enable smarter and faster triage.
• Continuously evaluate and tune models to reduce false positives and improve detection precision.
• Ensure model outputs are interpretable and actionable for SOC analysts.
• Build and maintain data pipelines to collect, process, and transform security-relevant data (e.g., logs, network traffic, endpoint events) into ML-ready datasets.
• Collaborate with security engineering team to ensure scalable and secure data handling (eg. parsing, processing, storage).
• Explore and build LLM-powered tools to automate repetitive SOC tasks (e.g., alert triage, evidence gathering, incident summarisation, report generation).
• Apply appropriate guardrails and evaluation to ensure outputs are accurate, auditable, and safe to act on in operational contexts.
• Stay current on advancements in security data science, adversarial ML, and automated threat detection.
• Prototype and test new ML and AI techniques (e.g., unsupervised anomaly detection, graph-based threat correlation).
• Contribute to improving detection content through statistical analysis and clustering.
• Deploy models into production securely and responsibly, ensuring reliability and scalability.
• Implement monitoring, alerting, and retraining mechanisms for deployed ML models.
• Document methodologies and performance metrics for auditability and knowledge sharing.

Requirements

• Proven experience in machine learning engineering or data science, ideally in a cybersecurity or operations context.
• Proficiency in Python, with strong knowledge of ML frameworks.
• Experience with data manipulation and analysis using Pandas, NumPy or similar tools.
• Familiarity with security data sources (e.g., SIEM logs, EDR telemetry, network flow, authentication logs).
• Solid understanding of ML lifecycle: data preparation, model training, evaluation, deployment, and monitoring.
• Experience with data pipelines and storage technologies (e.g., Airflow, Kafka, Redis, Elasticsearch, Clickhouse, etc.).
• Ability to work independently and collaborate effectively with both ML and security specialists.

Nice to Have

• Prior experience in threat detection, SOC operations, or security automation.
• Knowledge of adversarial ML, graph analytics, or behavioral modeling in security contexts.
• Experience integrating ML models into SIEM pipelines or automated detection frameworks.
• Exposure to LLMs and AI engineering (e.g., prompt engineering, RAG, agent design), and awareness of LLM-specific risks like prompt injection and data leakage.

Work Arrangement

On-site — Geneva, Zürich, Barcelona, London

What We Offer

• Work that Matters: millions of people trust Proton with their privacy. We answer only to our users — not advertisers, not investors with conflicting agendas, not governments. The work you do here is real, and the impact is measurable.
• Technology: you'll get the right hardware and the right software you need to do your best work.
• Learning & Development: we invest in your growth because sharp people make us better. Proton is one of the fastest ways to accelerate your career because you'll be thrown into real challenges, with real ownership, from day one.
• Employee Benefits: your wellbeing isn't an afterthought. We offer strong health coverage, solid retirement options, generous leave, and wellness support so you can bring your best self to work every day.
• Stock Options: at Proton, we all have the opportunity to be owners of the company. From day one, you have a real stake in what we're building. When Proton wins, you win.
• In-Person Collaboration: Amazing things happen when passionate, smart, and purposeful people get together in the same room. With offices across Geneva, Zürich, Barcelona, London and more, you'll spend most of your time collaborating face-to-face with people who genuinely care about what they're building.
• Food: Lunch and snacks are on us every day in our offices so you can focus on the work and not on what's for lunch.
• Transport: getting to the office shouldn't cost you. We cover public transport, bike allowances, or parking, whichever works for you.
• Flexible Working: you own your schedule. Set hours that work for you and your team — because outcomes matter more than when the clock says you started.

Our Commitment to Diversity and Inclusion

• 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.

Candidate Privacy Notice

• 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.
• 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.
• Proton does not accept unsolicited resumes from any sources other than directly from candidates.
• We will not pay a fee for any placement resulting from an unsolicited offer, even if the candidate is subsequently hired by Proton.

Additional Information

• Hiring at Proton is highly selective, with less than 1% of candidates hired.
• The company values intelligence, learning potential, and ambition.
• Proton has a flat structure to keep moving fast and avoid unnecessary politics.
• Employees receive stock options from day one.
• Flexible working: employees own their schedule and set hours that work for them and their team.
• Transport: public transport, bike allowances, or parking are covered.
• Food: lunch and snacks are provided daily in offices.
• Employee benefits include strong health coverage, solid retirement options, generous leave, and wellness support.
• Learning & Development: Proton invests in employee growth and career acceleration.
• Technology: employees receive the right hardware and software to do their best work.
• Proton is committed to diversity and inclusion and fosters an inclusive environment.
• If needed, candidates can request reasonable adjustments during the hiring process.