Software Engineer, Backend/Applied ML (Safety & Integrity)

About the role

We’re looking for a talented and creative Software Engineer to join our Safety Engineering team at Character.AI. In this role you will design, develop, and scale robust backend systems while applying machine learning to address critical integrity and safety challenges.

Key responsibilities

• Architect, build, and maintain highly scalable, resilient backend services that power integrity and safety features.
• Lead the design and implementation of sophisticated solutions for detecting, preventing, and mitigating integrity risks, including content classification, spam, and generative‑AI misuse.
• Conceptualize, develop, deploy, and iterate on machine‑learning models for content classification, anomaly detection, risk scoring, and bias mitigation.
• Collaborate cross‑functionally with product managers, data scientists, AI researchers, security, and operations to define requirements and deliver impactful systems.
• Define technical strategy and roadmap for backend integrity platforms and applied‑ML capabilities.

Required profile

• 8+ years of professional software engineering experience with a focus on backend systems.
• Bachelor’s, Master’s or PhD in Computer Science, Engineering or related field.
• Proven track record designing, building, and operating large‑scale, highly available distributed systems.
• Hands‑on experience applying machine‑learning techniques to real‑world integrity, trust or safety problems.
• Strong problem‑solving abilities and experience thriving in fast‑paced development environments.

Required skills

• Python, Go, Java, or C++ programming.
• Distributed systems design and implementation.
• Machine‑learning lifecycle: data preparation, feature engineering, model training, validation, A/B testing, deployment and monitoring.
• Content classification, anomaly detection, risk scoring techniques.
• Data engineering and performance optimization for large‑scale platforms.