DELAY @ vrch.ai

In a realtime ComfyUI workflow - the kind the ComfyUI Web Viewer pack is built for - everything fires constantly and nothing arrives when you expect it. The DELAY node is the boring, honest tool for that chaos: pass in any value, hold it, hand it back after a set number of milliseconds. That's the entire job, and being boring is the point.

What it is

Here's the whole mechanic. any_input accepts any type - a float, an image, a string, whatever - and the node parks it for delay_ms (0 to 10000 ms, default 0) before pushing it out as ANY_OUTPUT, unchanged except for the timing. Flip debug on and it prints timing info to the console while you're tuning. There are no hidden knobs, no magic. You put it in the wire, you get latency.

Why would you want latency on purpose? Two honest reasons. First, sync: in an interactive setup a control signal almost always arrives faster than whatever it's driving - a LivePortrait pass, a video decode, an upscale. A delay on the input side lines the trigger up with the slow part of the pipeline. Second, debouncing: controllers and key nodes can spam values in instant-queue mode, and a short delay turns a burst into one clean change instead of a flapping one.

The trap is the default. delay_ms starts at 0, which means the node is a pure pass-through - if you drop it into a normal one-shot queue and "nothing happened," that's not a bug. It only earns its keep when the graph re-runs constantly, i.e. ComfyUI's instant auto-queue or a sibling like the Instant Queue Key Control node from the same pack. In that mode the delay staggers when the downstream node sees each new value relative to when it arrived, which is exactly the "keep things in step" behavior you want.

How to install

Installing it is the same story as the rest of the pack. Search "ComfyUI Web Viewer" in ComfyUI Manager and install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/VrchStudio/comfyui-web-viewer
cd comfyui-web-viewer
pip install -r requirements.txt

Then restart ComfyUI. Windows portable users run the pip line with python_embeded\python.exe -m pip install -r ComfyUI\custom_nodes\comfyui-web-viewer\requirements.txt. No model files to download - this node is a few lines of Python, nothing else.

Common issues

One note if you're mixing this into a big graph: it's a * passthrough, so ComfyUI won't type-check what goes in. Feed it a number and you get a number back; feed it an image and you get that image back late. Just make sure whatever's on the other end of the wire is the same type you put in, or you'll get a confusing connection error. If you're still wrapping your head around why a delay matters at all, run a Web Viewer node in instant mode for five minutes - you'll feel the need for it almost immediately.