cloudflare_ns_change.sh

#!/bin/bash

# This POC uses the API's "registrar" endpoint to change NS delegation of a Cloudflare registrar domain to NS outside of Cloudflare

# export account e-mail address and Global API key. 
# Untested: New style APO token with appropriate perms may also work. 
export CF_API_EMAIL=user@server.com
export CF_API_KEY=changeme

# replace "changeme" below with your actual account ID and "domain.com" with the domain to be changed
curl -X PUT "https://api.cloudflare.com/client/v4/accounts/"changeme"/registrar/domains/"domain.com" \
     -H "X-Auth-Email: $CF_API_EMAIL" \
     -H "X-Auth-Key: $CF_API_KEY" \
     -H "Content-Type: application/json" \
     --data '{"name_servers":["ns1.namecheap.com","ns2.namecheap.com"],"privacy":true,"locked":true,"auto_renew":true}'
     
# Result should be something like: 
# {"result":{"message":"Domain updates complete!"},"success":true,"errors":[],"messages":[]}
# whois the domain to confirm 

Verification: