The future of AI is on-device. On the Siri team, we're solving the defining challenge: building and shipping powerful, LLMs that run with extreme efficiency across hundreds of millions of iPhones, Watches, and Macs. You will own the full ML stack, from data to deployment, bridging the gap between bleeding-edge research and product-critical models. This is where the hardest problems in applied ML are being solved. The frontier of AI isn't in the cloud anymore. It's in your pocket. The real chall