Where's the source code?

The source code will be released at the end of 2023.

Note: there was never any source code for the original txt2re.com and I wrote this site in PHP, basing it on Shaun Patterson's code (which was written in Perl with Public Domain license). I have made numerous fixes as well as added Unicode support to the original code. Compared to Shaun's code, it's more or less 60% total rewrite.