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
InvokeAI
Production-leaning SD studio with canvas & batch.
Open Source 8–16 GB VRAMRuns locally
Actually FreeNo SignupOpen SourceWatermark-FreeHobbyist-FriendlyAPIWorkflow Engine
Visit InvokeAIUpdated 2026-04-15 · Direct link
Hardware requirements
Runs locally · Mid GPU (12 GB)
Min VRAM
8 GB
Rec. VRAM
16 GB
Min RAM
16 GB
Rec. RAM
32 GB
Disk
40 GB
GPU class
Mid GPU
CUDA 12Apple Silicon ✓GPU RequiredQuant: FP16
SDXL recommended config wants 16 GB VRAM for comfortable use.
Screenshot placeholder · InvokeAI
What is InvokeAI?
InvokeAI is a polished Stable Diffusion studio with a real canvas, layers, and a queue. Better UX than A1111 for actually finishing images, with a cleaner backend for teams.
Pros & cons
Pros
- Best canvas in OSS SD
- Clean queue system
- Good docs
Cons
- Smaller plugin ecosystem than A1111
- Newer-model support lags ComfyUI
What's actually free?
Community edition is free + OSS. Paid Pro tier for teams.
✓ 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