Thanks for this nice tool to create a bitcoin invoice. It looks nice.

It will be difficult for anyone to use this service because the code is on your server. You can replace the address with your own address or makes the QR code different to the displayed address. You can also change the amount on the invoice and "take a cut". You may not do it, but no business can trust you not ever doing it.

Alternatively, you can host the code on github and share it.