Websites loading from app.birdie.so

Questions

Which websites load from app.birdie.so?

The 975 sites listed on this page. A site is listed when its stored HTML has a script, iframe or stylesheet from the host, or one of its own scripts names the host in an absolute URL.

Is app.birdie.so a third party for every site listed?

Yes: a host under a site's own registrable domain is never recorded for that site, so every site here loads from app.birdie.so as a dependency outside its own domain.