compressed-tensors is a production-grade Python library for compressing and quantizing large neural network models, primarily targeting LLMs. It extends the safetensors format to store and manage compressed tensors, supporting a wide range of quantization schemes (INT4/INT8/FP8/NVFP4/MXFP4/MXFP8), sparsity patterns, and rotation-based transforms (Hadamard, random matrix). The library is tightly integrated with the vLLM inference engine and Hugging Face transformers, providing a seamless path from model compression to deployment. Its architecture is modular: a registry pattern for compressors and transforms, a quantization lifecycle with calibration and forward hooks, a flexible offloading subsystem (CPU/disk/distributed) for running models beyond VRAM limits, and checkpoint conversion pipelines for formats like AutoAWQ and ModelOpt NVFP4. While primarily a software library, it also serves as a research platform for novel quantization techniques, with benchmarks and experimental features like MoE expert pruning and KV cache quantization. The codebase is well-structured with extensive tests, CI/CD pipelines, and active maintenance, though it exhibits some coupling to vLLM internals and experimental components that may not be stable.