I use NextDNS, but found managing allow-/denylists through the UI tedious, especially since I like to sync lists between profiles and keep them in version control.
So Claude and I built nextdnsctl, a small Python CLI that lets you manage lists via the official API.
pip install nextdnsctl
# get your key from https://my.nextdns.io/account
nextdnsctl auth <api-key> # or set NEXTDNS_API_KEY
nextdnsctl profile-list
nextdnsctl denylist import "Router Profile" ./blocklist.txt