Yes, it's our Parse API. You can find a complete guide on how to use it here: http://dev.mailjet.com/guides/parse-api-guide/

Any question, don't hesitate!

Hi,

I'm working at Mailjet.

You can find our API documentation and our existing wrappers on https://dev.mailjet.com.
For you need, you might be interested by our NodeJS wrapper: https://github.com/mailjet/Mailjet-sendemail
Also, we would more than happy to help you write one for NodeBB.
Feel free to contact us at [email protected].

Best,
Arnaud.