neosdconv-web
This is neosdconv running in a website. So instead of having to install Node and use the command line to convert a ROM to .neo, you can just drag your files onto the website.
Deployed here: https://toneosd.mattgreer.dev/
implementation
neosdconv-web uses neosdconv internally, and it all happens client side. If you were wondering why neosdconv switched from Buffers to Uint8Arrays, this is why.