Request: Option for private API URL

[JustJarethB]

The CLI and API options are convenient often but there are use cases where the CLI is not feasible and the user may not wish to use the MJML API. Perhaps we could provide our own endpoint with optional key/appId, allowing a custom/private server instead of the public server. This can:

• lighten the load on MJML servers
• allow for faster response if the MJML servers are busy
• have a fallback should something happen to the API service

[sjelfull]

This is a good suggestion, but you would need to implement a endpoint that matches the signature of the official API - which is non-trivial for most users.

I'm open to someone making a PR for this, but I won't touch this for now.

[jamesmacwhite]

@sjelfull Revisiting this due to the open API not having any formal SLA for production usage. While it works, this is a bit of a concern, in addition you may not be able to run the CLI on a production environment if its cloud based or PaaS. There are self hosted options out there that implement the same API with the render endpoint.

Would you be open to allowing the API endpoint to be config variable to switch out. I don't think there would be anything major to change, as the idea if any third party API implements the render endpoint the same.

E.g. https://github.com/danihodovic/mjml-server