Fine-tuning massive LLMs used to be painfully slow, but not anymore! 4 open source libraries that accelerate fine-tuning of Large Language Models 1. Unsloth AI • Fine-tune models like Qwen3, Llama 4, and Gemma 3 up to 2× faster with 70% less VRAM • Uses optimized Triton kernels and manual backprop for exact accuracy • Supports low-resource setups and runs on consumer GPUs or even Colab/Kaggle with ~3 GB VRAM GitHub repo → 2. LLaMA Factory • Fine-tune over 100 models (LLaMA, Mistral, Gemma, etc.) using a simple CLI or WebUI • Supports LoRA, QLoRA, full or frozen fine-tuning across 2–8‑bit precision • Includes built-in dataset templates, training monitors, and model export options GitHub repo → 3. DeepSpeed • Built for large-scale distributed fine-tuning with ZeRO and FSDP • Optimized for multi-GPU and multi-node training with advanced memory management • Trusted in production environments for scalable LLM training GitHub repo → 4. Axolotl • Yaml-based setup for fine-tuning, LoRA/QLoRA, DPO, GRPO, and multimodal workflows • Includes kernel optimizations for memory-efficient training • Actively maintained with support for Hugging Face, model export, and inference GitHub repo →