Unsloth is a framework for fine-tuning large language models that makes training open-source LLMs up to 2x faster and uses 60-70% less memory compared to traditional methods like Hugging Face Transformers. It optimizes the training loop with low-level techniques while remaining compatible with the Hugging Face ecosystem. Key features include ultra-fast fine-tuning of 7B–70B models on a single GPU, support for LoRA, QLoRA, and full fine-tuning, an open-source free tier, a no-code web interface called Unsloth Studio, and export options to GGUF, vLLM, and Ollama. In 2026, Unsloth has become a go-to choice for thousands of developers. Downsides include a primary focus on training and fine-tuning rather than inference optimization, potential waiting for support of very new model architectures, and best performance requiring compatible NVIDIA GPUs. It has a rating of 4.9/5 stars.