# Backend support

**SD.Next** supports two main backends: *Diffusers* and *Original*:

- **Diffusers**: Based on new [Huggingface Diffusers](https://huggingface.co/docs/diffusers/index) implementation  
  Supports *all* models listed below  
  This backend is set as default for new installations  
- **Original**: Based on [LDM](https://github.com/Stability-AI/stablediffusion) reference implementation and significantly expanded on by [A1111](https://github.com/AUTOMATIC1111/stable-diffusion-webui)  
  This backend and is fully compatible with most existing functionality and extensions written for *A1111 SDWebUI*  
  Supports **SD 1.x** and **SD 2.x** models  
  All other model types such as *SD-XL, LCM, Stable Cascade, PixArt, Playground, Segmind, Kandinsky, etc.* require backend **Diffusers**