@vaporeon_ the HTML5 part of the W3C validator has supurrt fur offline usage; you can clone it from https://github.com/validator/validator/
idk about older versions of HTML. maybe you could hack the perl CGI scripts of the full validator somehow? (https://github.com/w3c/markup-validator/)
@aescling (By the way: Do you know Perl? And if so, maybe you could look over my Perl scripting a few posts below?)
@vaporeon_ not really, sorry
@aescling Alright
(Did I ever ask: which programming languages do you know?)
languages i know but am rusty at:
@aescling Rust-y at C
@aescling Oh, Perl scripts! That certainly would be more appealing that running Java on my tiny server with 512 MB of memory...