MJML sending via API
In addition to the "text" and "html" parameters of the "messages" API endpoint, add another "mjml" parameter. Mailgun should automatically generate the HTML from the MJML and send the email.
Currently, an intermediary trip to the MJML API (https://mjml.io/api) is required (which is still in beta, so that it might be unsuitable for use in production) in conjunction with the Mailgun API or a custom Node.js service for parsing the MJML before sending it to Mailgun has to be set up.
Seeing as Mailgun and Mailjet/MJML are owned by the same entity, it would be good if this integration were natively built to the Mailgun API so that the above workarounds can be avoided.