The Machine Learning Engineer will design, develop, and optimize on-device machine learning models for learning user preferences within the App Store ecosystem. The engineer will implement, benchmark, and fine-tune deep learning models for efficiency, latency, and power consumption on iOS devices. They will work with Core ML, Metal, and other Apple ML frameworks to deploy models efficiently and securely. The role emphasizes on-device computation to ensure user privacy while developing personalized experiences using Private Federated Learning and Differential Privacy techniques. They will also optimize models for various iOS devices and develop tools for model compression, quantization, pruning, and hardware acceleration. This role requires staying current with advancements in privacy-preserving AI, on-device learning, and Apple ML.