I wrote this little webapp thing some time ago. It’s not exactly what you asked for but is a good example.

All it does is base64 encode a link and adds the server url in front of it. When someone visits that link it will redirect them to the destination. The intent is to bypass simple link tracking / blocking in discord and other platforms.

There are also checks for known bad domains and an attempt to remove known tracking query parameters.

git.tsps-express.xyz/liliumstar/redir