Load From JSON File

The other JSON nodes in this pack are precise instruments - get this key, pull that index. Load From JSON File is the blunt one: it reads a whole JSON file and hands you the entire thing as a string, in whatever formatting you want. It's the fastest way to get a config file or a saved result set back into your graph when you don't care about cherry-picking fields yet.

It's part of JasonHoku's Lite Text to File Tools pack, and it complements the write side perfectly: Save Text Into JSON and the array builders put data on disk, this node drags it back out as one blob you can dump into a Show Text node, an LLM, or a text-processing chain.

How it works

Two inputs. file_prefix is the path relative to ComfyUI/output/ (default text/lite-text.json). output_format is the dropdown that makes this node interesting, with three choices:

• pretty (default) - json.dumps with 2-space indentation. What you actually want for reading.
• compact - the whole file on one line, no whitespace. Good if the string is going into a parser or a JSON-valued prompt that hates stray whitespace.
• array_items - only meaningful when the file holds a JSON array: each item becomes a line in the output, so a 50-item array becomes a 50-line string. For non-array data it just stringifies the value.

The single json_content output is a plain STRING, ready to wire anywhere. Note this node is not an output node, which just means it's a data source - wire its output onward and it participates normally.

The usual gotchas

• Invalid JSON in the file → you get an error string out: Error: Invalid JSON - .... As with the rest of the pack, that error flows downstream as a string instead of failing the graph, so an unreadable file quietly pollutes whatever you feed the result into.
• Missing file → Error: File not found at ... as the output, same soft-failure pattern.
• array_items on an object - it just prints the object. Fine, but if you were expecting per-value lines, you grabbed the wrong format.

Installing it

It ships in the Lite Text to File Tools pack:

cd ComfyUI/custom_nodes/
git clone https://github.com/JasonHoku/comfyui-lite-text-to-file-tools
# restart ComfyUI

Or use ComfyUI Manager and search "Lite Text to File Tools". Pure standard library - no pip deps, no models.

Where it fits

Load a settings file into a Show Text node to eyeball it mid-run, or pull a saved array into a text-processing node to parse. If you need one field out of a key-value file, the pack's Load Text From JSON From Key is the sharper tool; this one is for when "give me the whole file" is exactly what you mean.