I used to work with Datadog and pingdom where there is a readily integration between the two that provides uptime and transaction time metrics that I can use in Datadog.

I'm now using Sumologic and Site24x7, but in the absence of a readily integration, I resorted to writing a script that calls Site24x7 APIs to obtain the performance metrics and then ingest them to Sumo. This solution works but doesn't scale up well a large number of monitors (in our case ~5000).

I hope you can look seriously into this feature request.