Jan

Jan is a desktop application for running open-source large language models on your own PC. It supports models such as Llama and Mistral, delivering Q&A, writing, and reasoning through a clean chat interface—entirely offline, with all data stored on your local drive to eliminate privacy risks. On the plus side, Jan is completely free and open source (once reaching over 18k GitHub stars). Its built-in Cortex engine can switch between backends like llama.cpp and TensorRT-LLM, supports GPU acceleration, and offers a local API server for developer integration. A no-code GUI lowers the entry barrier, while extensions allow advanced customization. The main hurdle is hardware: running LLMs locally demands a capable GPU and ample memory; low-spec machines will suffer slow responses and degraded output. Downloading some models relies on Hugging Face, which may require mirror sites under unstable networks. Local models also naturally trail cloud counterparts in scale and peak capability, and official support is limited to community channels. Jan costs nothing to use, but you need a suitably powerful computer (ideally with a mid-to-high-end GPU).