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Glossary · ComfyUI Basics

What Does Queue Prompt Do in ComfyUI?

By Earngenix Team ·

⚡ Quick Answer

Queue Prompt is the button that actually runs your workflow. Clicking it sends the current node graph to ComfyUI's backend for execution, adding it to a queue behind any generation that's already in progress instead of interrupting it.

Building a workflow just arranges nodes on the canvas — nothing generates until you click this button.

Where You'll See It

The button sits in the top-right corner of the ComfyUI window (labeled Run in some newer interface versions). A progress bar appears underneath it while a job executes, and the node currently being processed gets a highlighted outline on the canvas.

Quick Example

Click Queue Prompt, change the seed on your KSampler, then click it again before the first job finishes. Both generations run in order — you can watch them both waiting in the queue sidebar rather than one overwriting the other.

ComfyUI caches each node's output and only reruns the nodes whose inputs actually changed since the last click, which is why re-queueing after a small tweak often finishes much faster than the first run.

Frequently Asked Questions

This usually means ComfyUI is still starting up, a required model hasn’t finished loading, or a node in the graph is missing a required input. Check the terminal window for the actual error — it prints there even when the interface doesn’t show much.

Yes. The queue sidebar lists every pending and running job, each with its own cancel/remove control, so you can clear a mistaken click without restarting ComfyUI.

ComfyUI caches the output of each node and only recomputes the ones whose inputs actually changed. If you only tweaked, say, the seed on a KSampler, everything upstream of it reuses its cached result instead of rerunning.

See It In Action

New to running workflows?

Our beginner's guide walks through your first generation start to finish.

Published: 2026-09-17 · Last updated: 2026-09-17

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