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
AUTOMATIC1111 (stable-diffusion-webui)
The original SD power-user webUI.
Open Source 4–12 GB VRAMRuns locally
Actually FreeNo SignupOpen SourceWatermark-FreeHobbyist-FriendlyAPIWorkflow Engine
Visit AUTOMATIC1111 (stable-diffusion-webui)Updated 2026-04-30 · Direct link
Hardware requirements
Runs locally · Mid GPU (12 GB)
Min VRAM
4 GB
Rec. VRAM
12 GB
Min RAM
16 GB
Rec. RAM
32 GB
Disk
30 GB
GPU class
Mid GPU
CUDA 11.8+Apple Silicon ✓GPU RequiredQuant: FP16, --lowvram, --medvram
Runs 4 GB cards with --lowvram, but expect long generations.
Screenshot placeholder · AUTOMATIC1111 (stable-diffusion-webui)
What is AUTOMATIC1111 (stable-diffusion-webui)?
The classic Stable Diffusion WebUI. Less flexible than ComfyUI for novel models, but still the best place to learn parameter-driven SD/SDXL with a huge extension library (ControlNet, Roop, ADetailer, Regional Prompter).
Pros & cons
Pros
- Approachable forms-based UI
- Massive extension ecosystem
- Great for learning core SD params
Cons
- Slower to adopt new models
- Gradio UI feels dated
- Less efficient than ComfyUI on big workflows
What's actually free?
Fully free / open source. Hundreds of community extensions.
✓ Actually FreeNo SignupOpen SourceWatermark-Free
Alternatives
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
Stable Diffusion WebUI Forge
Optimized A1111 fork for low-VRAM cards.
Open Source 4–8 GB VRAM
- Min VRAM
- 4 GB
- GPU class
- Entry GPU
- Quant
- FP16
Actually FreeNo SignupOpen SourceWatermark-Free