Sometimes for your work you need to be reactive for specific customer even if they contact you during non-work-hours. That is why "e-mess" API has been created, an API between gmail and facebook messenger so as to receive directly urgent emails on messenger app.
The aim of this API si to be directly in the known and then be more reactive. With this API, when you're not available on you professionnal email address, you can still receive the text emails from important customer on your Messenger App. It allows people to be ready for urgent problems or requests.
E-mess is useful for every workers at least if they use a professional address but also messenger app from facebook. But the specific target is people who are working in digital on different projects and connected with people from all over the world and who need to be off sometimes but still stay connected with specific professional people.
This video describes you the general steps to create an API with Zapier. This video may help you to follow the steps mentionned above about the "e-mess" API.