Hello,
Since WordPress is written in PHP, and Ninja Forms is a non-default placement, users are welcome to implement using our PHP Library on their own. Users can use the PHP Library that is included with the Solve Media WordPress plug-in, or download the library directly from our PHP Help Page.
In the future, as we evaluate possible placements to add as default placements, we will take Ninja Forms into considerations, however, there are no current plans to extend to Ninja Forms. In the mean time, it may be beneficial to contact Ninja Form about adding the Solve Media CAPTCHA as a default SPAM option. You may also try implementing on your own, with our instructions, however, implementation requires some experience with PHP.
It appears that you have incorrect links to the Solve Media help pages. You can find the Implementation overview here:
https://portal.solvemedia.com/portal/help/pub/implement
You can find the PHP Help Page here:
https://portal.solvemedia.com/portal/help/pub/php/
Regards,
Kyle
