Free tool
Nixie tube maker
Type your words and watch them light up, one tube per character. Pick a look and a display face, set the size and background, tune the glow, then download a PNG or copy a link to what you made. It all runs in your browser, and it’s yours to keep.
The real thing
This is the same renderer that powers Nixietyper: each tube built on its own, composited in linear light, with the glare from all of them laid over the picture at once. Read how it works on the Nixietyper page.