BMAB SD-WebUI API Server

What it is

This one's a bridge, not a generator. BMAB SD-WebUI API Server points ComfyUI at a running Automatic1111-style install and hands you back a connection you can plug into the other three nodes in this family - T2I, I2I, and ControlNet. Instead of generating inside ComfyUI, you're remote-controlling a separate webui instance's REST API from inside your ComfyUI graph.

Why would you want that? Mostly legacy reasons, and they're honest ones. Maybe you've got an A1111 or Forge install with a checkpoint, LoRA, or extension setup you never bothered porting over. Maybe it's running on a different machine with its own GPU. Either way, this node lets you keep using it as a "generation backend" while doing the rest of your pipeline - masking, upscaling, compositing - in ComfyUI. It's a niche use case and it shows: this whole node family barely comes up in ComfyUI discussion online, which tracks with A1111 itself being frozen since mid-2024. If your target is Forge or Forge Neo instead of the original A1111, this should still work fine, since Forge kept the same UI and, as a fork of the same codebase, almost certainly the same /sdapi surface A1111 pioneered.

Inputs and outputs

Three fields, all required:

• server_ip_address - where the webui is running. Defaults to 127.0.0.1, i.e. the same machine.
• server_port - defaults to 7860, A1111/Forge's standard webui port.
• checkpoint - a dropdown of models. This one's populated live by querying the server, not baked into the node - meaning it's empty until BMAB can actually reach your webui instance.

The single output is server, typed API Server. That's the wire you plug into T2I, I2I, and ControlNet downstream.

How to install it

Grab it through ComfyUI Manager - search for comfyui_bmab and it'll offer to install the pack plus its two required dependencies in one go: comfyui_controlnet_aux (Fannovel16's preprocessor pack) and ComfyUI_IPAdapter_plus (cubiq's). Manual route:

cd ComfyUI/custom_nodes
git clone https://github.com/portu-sim/comfyui_bmab.git
cd comfyui_bmab
pip install -r requirements.txt

Then clone and pip install -r requirements.txt for the two dependency packs the same way, and restart ComfyUI. Windows portable users swap pip for python_embeded\python.exe -m pip. Grounding DINO detection, which other BMAB nodes lean on, rides on transformers>=4.40.0 - no separate install needed there.

Common issues

The one that trips people first: nothing shows up in the checkpoint dropdown. That almost always means the webui isn't running yet, or it's running without the API flag enabled - A1111 and its forks need to be launched with --api for this whole node family to have anything to talk to. Start the webui first, then load or refresh the ComfyUI graph.

If the server lives on a different machine, server_ip_address needs to actually be reachable - check firewalls and that the webui was launched listening on something other than localhost (--listen), or the connection will just time out.

And a mismatch worth knowing about upfront: ComfyUI and your webui instance are two completely separate installs with separate model folders. A checkpoint or LoRA you just dropped into ComfyUI's directory won't magically appear in this node's dropdown - it has to live where the webui itself looks for models. Easy to forget when you're used to everything living in one place.