Upscaler Downloader

The name overpromises. UpscalerDownloader doesn't upscale anything, and it isn't a catalog of models you can browse. It's a file manager for upscaler weights: it takes a URL, downloads the model file into ComfyUI's upscale_models folder, and lists what's already sitting there. That's the whole job, and it does it with almost no moving parts.

Why would you care? If you've ever hand-rolled an upscale workflow, you know the drill: find 4x-UltraSharp or a RealESRGAN anime model on HuggingFace, wget it, then hunt for where ComfyUI actually looks for it. The ESRGAN family is still the right answer for the "more pixels" rung of upscaling - instant, no hallucination risk, tiny VRAM - and this node just removes the terminal step from grabbing those files.

First, the honest part: the node does nothing

Add UpscalerDownloader to your canvas, type in the two inputs, run the graph - nothing downloads. The node's own function is a stub that returns an empty tuple, with a comment in the source that says "Real download handled via HTTP endpoint." Don't feel dumb; the README doesn't warn you.

The real interface is a web page at http://localhost:8188/upscaler_downloader, plus a button ComfyUI adds to its menu (the same one that opens the page). That's where downloads actually happen.

What the web page does

The form asks for two things, which are the same two inputs the node exposes:

• upscaler_name - the filename to save as, like 4x-UltraSharp.pth. Include a subfolder if you want one; it's created automatically.
• download_url - where to fetch it from.

The file lands in ComfyUI/models/upscale_models, which is exactly where the built-in UpscaleModelLoader node looks. So the flow is: download here, then wire UpscaleModelLoader → ImageUpscaleWithModel in your graph like normal. After a download, refresh the loader's dropdown.

Two behaviors worth knowing. Files that already exist are skipped with a "already exists" message, not overwritten - great when a model is a few hundred MB and you re-run the form by accident, mildly annoying if you downloaded a corrupt copy (delete it first). And there's a "download to local" / "download all" feature that serves your model files back through the browser. If you run ComfyUI on a rented GPU box, this is quietly the best part of the pack: it's the only built-in way to pull a model you downloaded on the server back onto your own machine.

Install

ComfyUI Manager, searching "Upscaler Downloader for ComfyUI", or manually:

cd ComfyUI/custom_nodes
git clone https://github.com/huihuihuiz/upscaler_downloader

Then restart ComfyUI. Dependencies are a single requests line - nothing heavy, no bundled model downloads. This is the rare custom node that installs instantly.

The catches

The interface is entirely in Chinese - menu button and all. It's simple enough to navigate blind: the big green button is "download", the blue buttons are "refresh list" and "download all". If it bothers you, your browser's translate is fine.

The bigger one is trust. This tool downloads whatever URL you hand it and drops it in a folder ComfyUI will happily load as a torch model - and loading a model is executing code. Same rule as downloading by hand: only pull from HuggingFace, Civitai, or official repos. The author does ship a safe_join check that blocks path-traversal writes outside upscale_models, which is more than most such tools bother with.

Fair warning: this is an obscure pack - no community footprint to speak of. You might be its only user. For a one-job utility that saves you a wget and a folder hunt, that's okay.