Stability Remove Background

Remove Background is the pack's most self-explanatory node: image in, cutout out. No prompt, no settings to speak of, one required input. It calls stable-image/edit/remove-background on Stability's servers, and the result comes back as an image with real transparency - an alpha channel, ready to drop onto any other background.

The honest framing up front: background removal is the most commoditized job in this entire ecosystem. The local answer - BiRefNet in core ComfyUI, or rembg - is free, fast, and as of 2026 the community default for anything with difficult edges. "Can it survive flyaway hair" is where these things are judged, and local models are very good at it now. So the case for this node is narrow: no local capability, or you want it inside an all-cloud workflow. It's a cloud node, costs credits, needs a Stability API key, uses zero VRAM - and per the pack's standing reception, "not local, not interested" is what you'll hear from people with a working local setup.

How it works

image in. output_format (png/webp/jpeg) if you care. An IMAGE out. That's it.

The one thing worth actually knowing is the transparency detail: the node returns an RGBA image, and if you save it as anything but PNG the alpha channel quietly dies. Use png for anything where the cutout is going to be composited. The api_key_override field behaves like the rest of the pack - the key comes from SAI_API_KEY, a sai_platform_key.txt file beside the node, or that per-node field (which embeds the key in the workflow, so don't share those files).

It's also synchronous and quick - no polling, no waiting for a background job. You feed, it cuts, you're done.

Installing it

From the "Stability API nodes for ComfyUI" pack - ComfyUI Manager, or:

cd ComfyUI/custom_nodes
git clone https://github.com/Stability-AI/ComfyUI-SAI_API
# restart ComfyUI

No models download; requests is the only dependency beyond ComfyUI's own stack.

Common issues

• Cutout has no transparency - you saved as jpeg/webp, or something downstream flattened the alpha. Check your Save Image node is set to png and your pipeline preserves the alpha channel.
• Hair and semi-transparent edges look rough - the shared curse of every background remover, local or cloud. There's no knob here to fix it; if edge quality is your bottleneck, this node won't beat a local BiRefNet pass.
• "payment_required" - credits ran out.

For a one-click cutout it's genuinely convenient. For serious production work with hair, fur, or glass, the free local models are still the better tool - this node just doesn't need you to have a GPU to get a usable result.