back4app have nice support
Well, I’m not yet finished with migration, but so far I’m convinced that back4app have great support.
I tried another service first, also mentioned in this post. Good service, but I stumbled upon certain problem while trying to enable webhook. Their support answered with some canned “have you read our tutorial?” and ignored my replies (maybe something broke with their support system, I don’t know). Only then I tried another service “back4app”, didn’t even enabled paid plan (I was on paid plan, although cheap, on first one), asked about same issue — had skype chat with two guys, trying to resolve it during two days, and finally managed to do it (and hopefully they will send PR to parse-open-server to handle this issue for everyone). So, point goes to back4app.