FF Text

Let's get the naming out of the way: "FF Text" sounds like a general-purpose text node, and it is not one. It takes a format string, reads the current date and time, and spits out a formatted string. That's the whole job. There are no static labels, no concatenation, no prompt templating here. What it is genuinely good for is one very common ComfyUI need: stamping the moment of generation onto something, so a filename never silently overwrites your previous output.

How it works

You give it one input, format_string (a multiline text box, default %yyyy-MM-dd HH:mm:ss%), using FF-Text's own %token% syntax:

• %yyyy% → 4-digit year, %yy% → 2-digit year
• %MM% → month, %dd% → day
• %HH% → 24-hour, %mm% → minutes, %ss% → seconds

The node scans for %...% blocks, converts them to Python's strftime codes, then formats the current time. Default input gives you something like 2026-08-16 14:23:45. The important implementation detail: it returns NaN from IS_CHANGED, so it always re-executes on every run. You get the time at generation, never a cached value from an earlier queue - which is exactly what you want from a timestamp.

What you wire it into

One output: text (STRING). Feed it into any string input on the canvas - the obvious one is Save Image's filename_prefix, so your outputs carry a unique timestamp and you never clobber yesterday's file. It also works as a run-time note into a display/text node, or as part of a dynamic prompt if you like your prompts timestamped. For filename stamping, that's basically the whole use case, and it does it with zero extra dependencies.

Gotchas

• It can't emit arbitrary text. Need a node that just holds "Hello world" or pastes a paragraph? Use a plain text/ShowText node. This one formats time, period.
• Case matters and it's easy to flip. %MM% is the month, %mm% is minutes - the opposite of what your muscle memory from other tools might guess. And %yyyy% vs %yy% is 4-digit vs 2-digit year.
• Watch your literal percent signs. Only %...% blocks get converted; everything else passes straight to strftime, and an unpaired % in ordinary text (say, "50% off") raises a ValueError that turns the node red. Keep stray percents out of the format.
• It's 24-hour with no AM/PM token. Fine for filenames, worth knowing if you wanted a 12-hour clock.
• Colons vs Windows. The default %HH:%mm:%ss% embeds : in the output - ComfyUI's prefix field is fine with that, but Windows filenames are not. If you're stamping filenames on Windows, use %yyyy-MM-dd HH-mm-ss% (dashes for the time part) or saving will fail.

Install

Part of fredhopp/comfyui-flipflopnodes - ComfyUI Manager (search "comfyui-flipflopnodes") or:

cd ComfyUI/custom_nodes
git clone https://github.com/fredhopp/comfyui-flipflopnodes.git

Restart ComfyUI. No models, and the declared requirements.txt deps (pillow/numpy/torch/piexif) are either already in ComfyUI or unused - this node only needs the Python standard library's datetime.

It's a tiny utility from a tiny pack, and "one light trick done well" is the right way to think about it. If you save files without timestamps and keep overwriting them, this is a five-second fix. If you needed a real text node, this isn't it - and knowing the difference is half the battle.