Print String

This is a debugging node, plain and simple, and its shape tells you exactly how it wants to be used: it takes a passthrough pin of type * (meaning literally anything - MODEL, IMAGE, CONDITIONING, whatever you've got), takes a separate in_string to actually print, and outputs that same passthrough value untouched. You splice it into the middle of an existing wire without changing what flows through it, and it prints in_string to the ComfyUI console as a side effect on the way past.

The reason the value you're inspecting and the value you're printing are two different pins is worth noticing: you don't have to be debugging a string. Wire your MODEL or IMAGE into passthrough so the graph keeps working exactly as before, and wire a separate string - a status message, a computed value converted to text, a parameter you pulled out with JNodes_GetParameterFromTable - into in_string so you can see it without adding a dead-end node that would otherwise stop your graph from executing anything downstream.

How it works

in_string gets printed. per_line, when enabled, prints each line of a multiline string separately rather than dumping the whole block as one console entry - handy when you're inspecting something like a wildcard expansion or a batch of file paths and want each item legible on its own line instead of buried in one wall of text. passthrough is returned unchanged as the node's own output, so anything downstream of it behaves exactly as if this node weren't there at all.

The inputs and outputs

• passthrough (*, any type) - the value you actually want to keep flowing through the graph.
• in_string (STRING) - the text to print.
• per_line (BOOLEAN) - print each line of a multiline string separately.
• * output - passthrough, unchanged.

How to install it

Via ComfyUI Manager: Install Custom Nodes, search "JNodes", install, restart. Or by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/JaredTherriault/ComfyUI-JNodes
pip install -r ComfyUI-JNodes/requirements.txt

then restart ComfyUI. No model downloads.

Common issues & troubleshooting

Nothing showing up. Console output means the server console - the terminal window running python main.py (or wherever your ComfyUI process's stdout goes), not the browser's dev console. If you're running ComfyUI in Docker or as a background service, check that container's or service's logs instead.

Wired in_string to the wrong thing and got a type error. in_string wants an actual STRING, not the arbitrary type passthrough accepts - you can't plug a MODEL or IMAGE directly into in_string; if you need to print something that isn't already text, convert it first (JNodes' own JNodes_AnyToString is built for exactly that).

Using it where a real "Show Text" node would be more useful. This node is for glancing at a value in the console mid-run without disturbing the graph - if you want to actually read the text in the UI itself rather than dig through server logs, a text-preview node is the better fit.