Since sendgrid is down (https://status.sendgrid.com/) ... again, does anyone have a recommendation on a service that will abstract sending emails.

We'd like a service that would present a single mail sending API, and automatically distribute outgoing emails between different providers (that we have accounts with individually).

It doesn't need to send the email itself, just act as a 'load balancer' for outgoing emails and detect when a given provider is having issues.

Bonus points if it can detect deliverabilty issues and adjust accordingly.