ComfyUI
The nodal workflow engine for serious diffusion.
Open Source 6–16 GB VRAM
- Min VRAM
- 6 GB
- GPU class
- Mid GPU
- Quant
- FP16
Actually FreeNo SignupOpen SourceWatermark-Free
Diffusers
Hugging Face's go-to library for every diffusion model.
Open Source 4–12 GB VRAMRuns locally
Actually FreeNo SignupOpen SourceWatermark-FreeHobbyist-FriendlyAPI
Visit DiffusersUpdated 2026-05-20 · Direct link
Hardware requirements
Runs locally · Entry GPU (6–8 GB)
Min VRAM
4 GB
Rec. VRAM
12 GB
Min RAM
8 GB
Rec. RAM
16 GB
Disk
15 GB
GPU class
Entry GPU
11.8+Apple Silicon ✓CPU-CapableQuant: FP16, BF16, FP8 +1
Hardware scales with the model you load.
Screenshot placeholder · Diffusers
What is Diffusers?
Diffusers is the Python library every diffusion model ships its first reference implementation against. SD, SDXL, SD3, Flux, AnimateDiff, Stable Video Diffusion — load any of them in 3 lines. Less polished than ComfyUI for end users, but the canonical way to call diffusion models from your own code.
Pros & cons
Pros
- Every new diffusion model lands here first
- Unified API across image, video, audio, 3D diffusion
- First-class quantization & memory-saving (offload, slicing, attention)
- Hub integration — `from_pretrained()` any model
Cons
- Library, not an app — you write the code
- Less optimized than a tuned ComfyUI workflow at the same VRAM
What's actually free?
Apache 2.0 from Hugging Face.
✓ Actually FreeNo SignupOpen SourceWatermark-Free
Alternatives
AUTOMATIC1111 (stable-diffusion-webui)
The original SD power-user webUI.
Open Source 4–12 GB VRAM
- Min VRAM
- 4 GB
- GPU class
- Mid GPU
- Quant
- FP16
Actually FreeNo SignupOpen SourceWatermark-Free
InvokeAI
Production-leaning SD studio with canvas & batch.
Open Source 8–16 GB VRAM
- Min VRAM
- 8 GB
- GPU class
- Mid GPU
- Quant
- FP16
Actually FreeNo SignupOpen SourceWatermark-Free