It's likely that unless you can claim status as a library or some other exception to copyright protections, as a commercial entity providing that service without compensating publishers, such a straightforward violation would get a bunch of takedown requests and eventual lawsuits for failure to respond to those requests, along with more suits if publishers have no easy way of opting out.

As a personal tool you built for yourself and your friend(s) nerdy enough to understand it, I wouldn’t worry too much about it, as long as no search engines index your site and no one finds out about it.