GSA and OPT IN PAGES works?

The bottom line here is - don’t use any automated link-building “service”. It’s against Google’s ToS and may lead to your site being penalised. https://support.google.com/webmasters/answer/66356?hl=en Bing likewise will penalise your site for Spammy tactics like this. https://www.bing.com/webmaster/help/webmaster-guidelines-30fba23a