Save String List To JSON JK🐉

ComfyUI workflows are great at using data and terrible at keeping it. Generate a camera trajectory, a prompt list, or a set of per-scene settings, and the moment you close the session it's gone - unless you save it somewhere. Save String List To JSON JK writes a string (or a parsed JSON list) to a file on disk, so your presets survive the restart. It's the write half of the pack's save/load JSON pair, and Jake built it for a very concrete reason: ATI trajectory presets for Wan video workflows.

What it does

Four inputs:

• string_input - the text to save. This can be a plain string or a JSON-formatted list.
• file_path - the full filesystem path to write to. No path, no save - it prints an error and bails.
• overwrite (default True) - if False and the file already exists, it skips writing and leaves the existing file alone. This is your "don't clobber my presets" guard.
• save_as (default True) - if True, it tries to parse string_input as JSON and writes it out pretty-printed (formatted with indentation). If False, it writes the raw string. If parsing fails, it falls back to string mode with a warning rather than crashing.

It also creates parent directories automatically, which is a small mercy - you don't need to pre-make the folder.

The output

string_output echoes back what you gave it. It's a pass-through for convenience (so you can chain a save into the rest of the graph without breaking the wire), not a result you should expect to be different.

When it's worth it

The canonical use: generate something expensive or finicky once - a camera path, a beat list, a curated prompt set - and save it. Next session, load it back with the pack's Load String List From JSON JK and skip the regeneration. It's also great for editing presets outside ComfyUI: save a list, tweak the JSON in a text editor, reload, and your workflow picks up the changes without a rebuild.

Note the v2.7.2 change: it now saves as a list by default rather than a raw string - so if you're passing a list-like string, save_as on is the behavior you want for round-tripping with the loader.

Install

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

No models, pure file I/O. Gotchas are the usual filesystem ones: give it an absolute path (relative paths resolve against the ComfyUI working directory, which is rarely where you think it is), and remember overwrite = False will silently skip - if you save, see no error, and the file looks stale, check whether overwrite got flipped off.