Starting from RouterOS v7.1beta4, Mikrotik has support for REST API, which can be used by FastNetMon to create or remove routes (typically blackholes) without using BGP.
Before beginning this guide, please read the official Mikrotik guide and enable the www or www-ssl service on Mikrotik.
To enable this capability, please upgrade FastNetMon to version 2.0.359 or more recent.
Then enable this logic in the following way:
sudo fcli set main mikrotik_announce_host true sudo fcli set main mikrotik_announce_host_blackhole true sudo fcli set main mikrotik_rest_api_urls https://admin:admin@192.168.1.131 sudo fcli commit
In addition to plain HTTP mode, we support encrypted HTTPS mode to access Mikrotik REST API, too.
After that, FastNetMon will create / remove routes on Mikrotik side whenever FastNetMon blocks/unblocks hosts:

To test that integration works correctly we recommend manually blocking and then unblocking some test host:
sudo fcli set blackhole 1.2.3.4
Then check the list of blocked hosts and get UUID of it:
sudo fcli show blackhole
To unblock the host, you need to use the UUID from the previous command and issue the following command:
sudo fcli delete blackhole d9b1885f-6d9b-4167-9e3e-0a3198bacee9

