The Mailgun email management API uses RESTful calls and responses are formatted in JSON. The API authenticates with an API Key over HTTP Basic Auth. Use Mailgun to do things like: send email, automate email services, and receive real-time notifications in app. Mailgun also offers email tracking and analytics. Note that the default version of this API is now v3. V3 is backward compatible with v2, but some endpoint behaviors have been modified. See the documentation for full details on the latest Mailgun API version.