Load Checkpoint (Model Manager)

The name sounds like the next boring loader node, but this one changes where your models live. Instead of picking a checkpoint out of ComfyUI/models/checkpoints, Load Checkpoint (Model Manager) grabs it from a Model Manager REST server - a self-hosted, Civitai-style model library with its own web UI - downloads it on first use, and caches it locally so it only downloads once. If you manage models on a central box (a team, a second PC, a rig where disk is precious), this is how you stop hand-copying 7 GB safetensors between machines.

What it actually does

The node is a drop-in replacement for ComfyUI's core Load Checkpoint node. When the graph runs, it:

1. Parses your dropdown selection into a model_id (and a version_id if the server has multiple local versions of that model - the dropdown entries are formatted modelId@versionId:name).
2. Asks the server to stream the file down (GET /api/v1/models/{id}/download), showing a progress bar in ComfyUI while it does.
3. Saves it to the cache directory (by default ComfyUI/models/model_manager_cache/checkpoints/, named with a {model_id}_{version_id}_ prefix).
4. Loads it with ComfyUI's normal checkpoint loader and hands you the three things every sampler graph needs: model, clip, vae.

So once a checkpoint is cached, runs are just as fast as a local install. The IS_CHANGED hook keys off the connection version, so the node re-resolves your dropdown when the server's model list changes or you reconnect.

The one input you care about

checkpoint is the only input, an enum populated from the server's Checkpoint category. Two states trip beginners up:

• (not connected) - you haven't connected yet, or your API key is bad. Click the Connect to Model Manager button on the node, enter your API URL and key. A wrong key gets a 401 and the dropdown stays dead.
• (error loading models) - the server is reachable but refused the list. Check the URL and that the server's actually up.

A small warning: this tool's "Model Manager" is a self-hosted API server. It is not the popular ComfyUI Model Manager browser (AIGODLIKE's studio) that a lot of r/comfyui posts refer to - that one renders thumbnails and doesn't need a server at all. Same name, completely different job.

Install

Easiest via ComfyUI Manager: search for comfyui-model-manager-nodes and install. Or clone it directly:

cd ComfyUI/custom_nodes
git clone https://github.com/blackpaw-studio/comfyui-model-manager-nodes
cd comfyui-model-manager-nodes
pip install -r requirements.txt

Restart ComfyUI, and the "(Model Manager)" family of loaders shows up under the loaders category. Dependencies are light - just requests and pyyaml - so there's nothing heavy to fight with. (Note the pack's README still points its clone command at an older upstream repo name; the one above is the current, working address.)

You'll need a Model Manager server to point it at. Set the connection in-node (recommended, it saves to config.yaml), via that file, or with MODEL_MANAGER_API_URL / MODEL_MANAGER_API_KEY environment variables - env vars win over the config file.

Troubleshooting

• First load is slow. You're streaming a multi-gigabyte checkpoint over the network. That's the deal; it only happens once per model version.
• Disk keeps growing. Every model you load lands in model_manager_cache. That's what the Clear Cache (Model Manager) node is for - it shows you the total and wipes it when you tell it to.
• (not connected) after a restart. If you used the in-node button, the credentials are persisted to config.yaml and auto-connect runs on boot. If it still shows disconnected, the saved key was rejected - re-connect or fix the file.

If your server organizes things by a separate "Diffusion Model" category instead of "Checkpoints", grab the Load Diffusion Model (Model Manager) node - same outputs, same behavior, different server folder.