The External Accounts API is used to manage accounts for Viber Business Messages, Facebook Messenger and Whatsapp for use in the Messages and Dispatch APIs.
curl \ -u "$API_USER:$API_PASS" \ https://api.nexmo.com/beta/chatapp-accounts/
curl \
-u "$API_USER:$API_PASS" \
https://api.nexmo.com/beta/chatapp-accounts/whatsapp/{external_id}curl \
-u "$API_USER:$API_PASS" \
https://api.nexmo.com/beta/chatapp-accounts/messenger/{external_id}