LocalChat.app is a local-first AI chat application for macOS that enables users to run and interact with open-source large language models (LLMs) entirely on their own device, without requiring an internet connection, cloud servers, or user accounts. Unlike cloud-based AI assistants, LocalChat.app processes all conversations directly on the user's Apple Silicon hardware (M1–M6). Models are downloaded once and run locally in GGUF format, meaning no data is transmitted to external servers at any point. The application is designed for individuals and professionals who require AI assistance while maintaining full control over their data and workflows. LocalChat.app supports over 300 open-source AI models from providers including Meta (Llama), Mistral AI, Google (Gemma), Alibaba (Qwen), and DeepSeek. Users can switch between models depending on the task without using a terminal or editing configuration files. Key features and capabilities include: - Document chat: Users can attach and query files including PDFs, spreadsheets, Word documents, and presentations using Retrieval Augmented Generation (RAG), allowing AI to reference specific document content in responses. - Vision support: Compatible models can analyze images, charts, and screenshots directly within conversations. - One-click model manager: Models can be browsed, downloaded, and switched through a built-in interface without any command-line interaction. - Offline operation: After the initial model download, the application functions with no internet connection, making it suitable for travel or restricted network environments. - Local encrypted storage: All conversations are stored and encrypted on the user's device. No telemetry, tracking, or third-party data sharing occurs. LocalChat.app is available as a one-time purchase with no subscription fees or recurring charges. It is designed for professionals in fields such as law, healthcare, finance, and software development where handling sensitive or confidential information requires data to remain on-device. The application requires no account creation or login to use.