Checkbin Submit Bin

What it's for

Checkbin Submit Bin is the finish line. After Start Run opened a run and your Save Image / Save String nodes filled the bin with candidates, this node calls bin.submit() and ships the whole thing to Checkbin for human evaluation. Once it runs, your comparison is live - you get a shareable snapshot link where people vote on which candidate wins, pair by pair.

It's an output node (no outputs, OUTPUT_NODE = True), which is ComfyUI's way of saying "this is a terminal action." It's where the workflow stops doing work and the humans start.

How it works

The entire implementation is one line of substance: bin.submit(). Everything else about the node is plumbing. Because Start Run returns a list of bins and ComfyUI fans lists out to the connected graph, Submit Bin runs once per bin - so a run over ten input images ends in ten submits, one complete comparison per input. No extra wiring needed; you just connect the bin output of your last save node here and let the list machinery do its thing.

There's no local processing, no GPU work, no file writing. This node is purely the "send it" button, and the state it sends lives on Checkbin's servers.

The inputs that matter

One required input: bin. Connect it to the bin output of your final Save Image Bin or Save String Bin. That's the entire input surface - which is refreshingly small, honestly.

And since it has no outputs, it's the natural end of the chain: wire bin from your last save node into Submit Bin and you're done building the comparison.

How it fits a real workflow

Putting it together with the shipped example: Start Run opens a run over a folder of test photos → Get Image Bin pulls each source image out → two parallel paths upscale it (Flux-ControlNet and SUPIR) → each Save Image Bin records its variant under flux_upscale / supir_upscale → Submit Bin fires and posts the pair for voting. The whole thing is the "workflow included" A/B test, and this node is the click that publishes it.

Installing it

One install covers all six nodes in the checkbin-comfy pack:

cd ComfyUI/custom_nodes
git clone https://github.com/checkbins/checkbin-comfy

Restart ComfyUI, or install through ComfyUI Manager by searching "checkbin-comfy". The only dependency is the checkbin package; there are no models to download and nothing heavy to compile. The real requirement is an account at app.checkbin.dev with a valid token in your Start Run node.

Common issues

• Submitting an empty or half-filled bin - if you wired Submit Bin to a bin before the save nodes ran, or a save node failed, you can publish a comparison missing a candidate. The order of the chain matters; make sure every slot is filled before the submit fires.
• Runs re-triggering - because Start Run always executes (its IS_CHANGED returns NaN), the whole chain including this submit runs on every queue. Each generate = another submit. Fine for a real test; surprising if you're just iterating on the workflow and accidentally publish a dozen drafts.
• It's final - once submitted, the data is with the platform, not recoverable from the local graph. Treat the first test as a dry run before you invite an audience.