NIX_StringMatch

NIX_StringMatch is the node you use when you care that 7 sorts before 12 in a filename. It takes an integer and pads it with leading zeros to a fixed width, outputting the result as a string. That's the entire job: serial_number and figure in, text out. It's a formatting utility, not a matcher - the name is a little generous, but the behavior is unambiguous.

This is a genuinely thin node, and that's fine. Padding numbers is a recurring annoyance in batch workflows, and having a one-input-one-dial node for it beats hand-rolling the logic every time you hit it.

How it works

• serial_number (required, INT, min 0) - the number to pad.
• figure (required, INT, min 1) - the total width. Default 5.

The output text is serial_number zero-filled to figure digits. Examples with default figure of 5:

• 7 → 00007
• 42 → 00042
• 100000 → 100000 (already wider than 5, so no padding happens)

Numbers wider than the width are left alone - it never truncates, only pads.

Where it slots in

The classic use is filenames. If you're saving a batch of frames or variants, 00007.png sorts before 00010.png everywhere that matters - your OS, your video encoder, downstream batch loaders (like NIX_PathLoading, which has a natural sort anyway, but external tools usually don't). Wire text into a save node's filename_prefix alongside the counter that drives your loop.

It's also the natural companion to NIX_XYGridMapper's name output if you want zero-padded grid-sweep names, or any iterator that hands you an index and you need a string.

Getting it installed

One install covers the whole NIX pack - no models, no heavy deps:

• ComfyUI Manager: search "NIX" / "NIX ComfyUI Plugin", or Install Custom Nodes → Git URL → https://github.com/J-ChenX/ComfyUI-NIX. Restart after.
• By hand:

  cd ComfyUI/custom_nodes
  git clone https://github.com/J-ChenX/ComfyUI-NIX
  

  Restart ComfyUI. Under the "NIX" category.

Gotchas

• It only pads. Feed it a float and you'll want a cast upstream - the input is INT.
• No truncation. figure: 3 with serial_number: 12345 returns 12345, not 345. If you need a fixed-length trimmed number, look elsewhere.
• Quiet pack. No community discussion around NIX as of mid-2026, so this is a "read the source if unsure" situation - and the source is four lines, which is exactly as reassuring as it sounds.