Tutorial: Run LLMs Locally on Mobile Using React Native and Expo

A new developer tutorial demonstrates how to run large language models directly on a user's device using React Native and Expo, requiring no server or API key. The guide uses the open-source NobodyWho library, which wraps llama.cpp in Rust and exposes a React Native API for running GGUF-format models locally. Models can be automatically downloaded from Hugging Face, cached on first use, and reloaded on subsequent app launches without manual management. On-device AI offers key advantages over cloud-based approaches, including offline functionality, user privacy, lower latency, and zero inference costs. The tutorial covers a range of features from basic chat to multimodal input, speech-to-text, voice detection, tool calling, and retrieval-augmented generation.