Machine Learning Engineer, Safety

About xAI

xAI’s mission is to create AI systems that can accurately understand the universe and aid humanity in its pursuit of knowledge. Our team is small, highly motivated, and focused on engineering excellence. This organization is for individuals who appreciate challenging themselves and thrive on curiosity. We operate with a flat organizational structure. All employees are expected to be hands-on and to contribute directly to the company’s mission. Leadership is given to those who show initiative and consistently deliver excellence. Work ethic and strong prioritization skills are important. All engineers are expected to have strong communication skills. They should be able to concisely and accurately share knowledge with their teammates.

About the Role

We are seeking a passionate and innovative Machine Learning Engineer to join xAI’s Applied Safety team, where you will drive the development of cutting-edge ML solutions to ensure compliance with X’s Terms of Service and enhance user safety. In this role, you will own the full machine learning lifecycle, building and deploying models to detect and mitigate threats like abuse, spam, and fraud, while fostering a secure and trusted global digital public square. Ideal candidates are creative problem-solvers who thrive in 0-to-1 environments, prioritize impactful code over documentation, and are excited to apply advanced ML techniques to high-stakes safety challenges.

Key Responsibilities

• Own the end-to-end machine learning lifecycle for safety systems, including data gathering, cleaning, model training, evaluation, and serving at scale.
• Develop and deploy ML models to detect and remediate violative content in areas such as abuse, spam, and child safety.
• Integrate models into production systems for real-time inference and high-throughput processing to support platform integrity.
• Apply creative problem-solving to design novel ML solutions for uncharted safety challenges.
• Collaborate with engineering, product, and operations teams to enhance xAI’s safety ecosystem.
• Lead technical initiatives in ML-driven areas like fraud detection or content moderation.

Required Qualifications

• 5+ years of experience in machine learning engineering or related roles.
• Proven expertise in managing the full ML lifecycle, from data preparation to model serving.
• Familiarity with modern data pipelines and ML infrastructure ecosystems.
• A passion for 0-to-1 environments, with a track record of trailblazing novel ML solutions.

Preferred Qualifications

• Prior experience in Trust and Safety or applying ML to content moderation challenges.
• Experience leveraging large language models (LLMs) for real-world applications, such as natural language understanding or anomaly detection.
• Fluency in Python, with proficiency in ML libraries like TensorFlow or PyTorch.
• Background in designing and managing scalable systems for large datasets.
• A passion for xAI’s mission.