- US Mailgunhttps://api.mailgun.net/v1/preview/tests/clients
- EU Mailgunhttps://api.eu.mailgun.net/v1/preview/tests/clients
curl -i -X GET \
-u '<username>:<password>' \
https://api.mailgun.net/v1/preview/tests/clientsResponse
{ "clients": { "android10_gmailapp_pixel4_dm": { … } } }