Send transactional emails with Mailgun.
The username is the text string "api" and password is your private api key.

Mailgun provides two types of API keys for authenticating against the API: Primary account keys and Domain sending keys.

1. You'll need to insert your private api key. This is never shared with the plugin. The username is the text string "api" and password is your private api key.


Domain Sending Keys:
"Domain Sending Keys are API keys that only allow sending messages via a POST call on /messages and /messages.mime endpoints for the domain in which they are created for."
To create a sending API key:

1. Go to the Mailgun Dashboard
2. Click the Sending tabon the left-hand side of the Mailgun dashboard
3. Click the Domains tab and select the domain in which you wish to add a sending key to
Click the Domain Settings and navigate to the Sending API keys tab
4. Click on Add Sending Key