Bad app will just brutally fetch it every time with not even a cache on its side. As a quick fix, there are many options for limiting per IP per timespan, e.g.

Bad app will just brutally fetch it every time with not even a cache on its side. As a quick fix, there are many options for limiting per IP per timespan, e.g. fail2ban, you could configure it to punish bad apps without crippling functionality for others. Well, maybe crippling a little bit in some very special use cases, still better than it simply not working.