I was wondering if these servers support APIs like this one. It allows new players starter kits etc.

https://survivetheark.com/index.php?/forums/topic/159821-server-plugin-shop-currency-kits-v23/

If so where are the install instructions? It seems to be different than just a mod.

Thanks

Nope.

ARK API is a windows program, these are Linux Servers.

Many of the server Admins on this host use Timmy Carbine's Auto Rewards as an alternative. Well documented, and in most cases able to allow you to reward players for supporting the server.