Preview Any

ComfyUI is a black box until you add previews, and the standard preview node only knows how to render images. So what do you do when you want to know what's actually coming out of a math node, a string builder, or a latent utility? Preview Any is the debug node that shows you the value of almost anything, inline, as text - up to 16 values at once.

What it is

A utility node with a single autogrowing inputs socket (labeled inputs) that you can connect one or many values to - up to 16. It has no outputs; it's a terminal node whose entire purpose is to display. It's marked experimental in the pack, and it's the lighter sibling of the pack's Debug Any node, which focuses on one value at a time.

How it behaves

The display logic is deliberately simple and practical:

• Primitives - strings, ints, floats, booleans - show as-is.
• Complex types - anything structured is serialized (to JSON where possible) so you can actually read it.
• Image tensors get a summary rather than a rendering: N images, WxH. That's the smart choice for a debug node - rendering 30 frames of video just to check a dimension is wasteful; the summary tells you what you need.

So it's the node you drop mid-graph when a downstream node is erroring on a value you can't see. Instead of guessing what's on a wire, connect it here, run, and read the result below the node.

Why you'd reach for it

• Debugging an error - something upstream is producing the wrong type or a None; Preview Any shows you the truth.
• Verifying math/logic - check that your Nifty Math expression or Number Compare actually outputs what you expect before it feeds a critical switch.
• Inspecting batch shapes - before a merge or a VAE encode, confirm the frame count and dimensions of an image batch with one glance.

It pairs well with the rest of the pack's logic and number nodes: build the condition, preview it here, then wire it onward with confidence.

Installing it

Part of the Nifty Nodes pack:

cd ComfyUI/custom_nodes
git clone https://github.com/Stibo/comfyui-nifty-nodes

or search "Nifty Nodes" in ComfyUI Manager, then restart. No models or dependencies.

Gotchas

It's experimental, so don't be surprised if it's a bit rough around the edges - its job is inspection, not production. And remember it's a text summary node, not an image preview: if you actually want to see frames, this isn't the node (the core PreviewImage is). For everything else - the values that were invisible before - this is the fastest way to make them visible. Keep ComfyUI updated, as the whole pack targets the newer V3 API.