Thank you for your post. I run ImprovMX and it's with pleasure that you liked using it :)

We are on the verge to release a sending feature and the decision from Mailgun to drop this came at a great surprise for us.

I always thought of Mailgun like the "unreachable competitor", kind of like "reach for the moon" type of target. But since they moved their forwarding feature to a costly paid plan, it's just like the moon vanished from our trajectory.

Anyway, I'm open to answer any questions if you have any. I also posted about ImprovMX here on HN today (https://news.ycombinator.com/item?id=22223783) and ready to answer all the questions there too.