🧳 Show Data

This is a debug node, plain and simple. You feed it something - a string, a number, whatever a wire is carrying - and it prints that value as text right on the node's face after the graph runs. No output, no processing, just "show me what's actually flowing through this link." Every graph reaches a point where you're squinting at a connection wondering what is that value, and this is the node that answers.

It ships in the RealESRGAN Upscaler pack for a specific reason: the upscaler emits a couple of STRING outputs - config_str (your local GPU/install details) and error_str (the readable message when something like a netscale mismatch goes wrong) - and those are useless dangling in the air. Wire them into Show Data and you can actually read them. That's the pairing the pack is built around: the upscaler does the work, Show Data lets you inspect what it reported.

How it works

It's an output node with no outputs - a terminal you hang off the end of a wire. ComfyUI treats it as a leaf that must execute, so it forces the value to resolve and then writes it into the node's text widget for you to see. Same idea as rgthree's Display Any, which "shows backend values after execution," or any of the various Show Text nodes floating around the ecosystem. If you've used one, you've used all of them.

The inputs

There are only two, and only one you interact with:

• input (type *) - the wildcard. That asterisk means it accepts any type, which is the whole point: you don't need a matching converter, just drag a wire from whatever you're curious about.
• data (STRING, multiline) - this is the display field. It's where the incoming value gets rendered as text after a run. You can leave it empty; it fills itself in.

There are no outputs - this is the end of the line. You can't chain anything after it, because there's nothing to chain. That's expected for a display node, not a bug.

Installing it

It comes with the whole pack, so there's nothing separate to install. ComfyUI Manager, search ComfyUI-RealESRGAN_Upscaler or the author zentrocdot, install, restart. Or by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/zentrocdot/ComfyUI-RealESRGAN_Upscaler

then restart ComfyUI.

One shared caveat that applies to everything in this pack: it leans on basicsr, which on recent TorchVision throws ModuleNotFoundError: torchvision.transforms.functional_tensor on load. If the pack's nodes red-box on first run, that's why - the fix is a one-line edit in basicsr/data/degradations.py (change the functional_tensor import to functional), or run the pack's scripts/fix.bash. It's documented in the pack README and worth doing once up front.

When it's not showing anything

If Show Data comes up blank, the usual cause is upstream, not the node itself: whatever feeds it never executed, or the value it's carrying is genuinely empty. Remember it only updates after a run completes - it reads backend values post-execution, so you won't see anything until the queue finishes. And because it's a terminal node, if it's not connected to a live branch of the graph, ComfyUI may skip executing it entirely. Give it a real, resolved input and it'll faithfully print whatever's there.