Unsloth

Unsloth builds open-source software for developers to train, fine-tune and run AI models locally. Its product family includes Unsloth Core, the code-based version; Unsloth Studio, a web interface; and Unsloth Desktop, available for Windows, macOS and Linux. Users can customize language, embedding and audio models, generate images and videos, and build training datasets from documents. The training tools support reinforcement learning, LoRA, QLoRA and full fine-tuning, with export formats for deployment.

Brothers Daniel Han and Michael Han founded Unsloth in 2023, and Daniel serves as CEO. Its engineering work includes custom kernels for model training, including Triton kernels for rotary position embeddings and multilayer perceptrons, alongside batching algorithms for longer-context reinforcement learning. The kernels, combined with padding-free training and packing, speed up training and reduce GPU memory use.

Its software supports CPUs and GPUs from multiple vendors, including NVIDIA, AMD, Intel and Apple Silicon. An OpenAI-compatible API lets developers serve local models to other applications, while coding-agent connections let users work with local models through tools such as Claude Code and Codex. Its GitHub repository had about 75,000 stars as of August 2026.