Host is a single application process in your app. Different hosting providers give different names to that. Containers, servos, dynos, drones, hosts are few of those names.
Kadira collects data from every hosts in your app. That's why we charge based on the number of hosts available in your app.
First we get a list of host usage for your app, aggregated for an hour. We take it for your current billing month. That means there are around 720(24 * 30) values for an app. Then, we take the median of those values for each app. We aggregate those medians and that's your monthly host usage.
That means, number of hosts usage stays the same even if your app had a sudden spike in the usage or you load tested your app.
Data Retention indicates the period of time we keep your application data with us.
Of course you can change plans anytime.
You can simply allow other members in your team to use Kadira UI to monitor and optimize your app. You can change the ownership to another user as well.
Collaborators can be added to any app, but there is no way to add account-level collaborators.
Kadira Alerts sends you a notification when something strange happens with your app. You can set alerts for almost every metric available in Kadira.
Kadira tracks both server and client errors for you automatically. You can use Kadira UI to analyze error traces and understand them.
Do you have any other questions? Please ask!
We are happy to help you out.