Poor response times office 365 REST API

I'm using the new office REST APIs in order to access Exchange data, the APIs are behaving as expected however the response times of the requests are hugely variable.

Below are the times recorder over 30 requests with a 10 second interval between each (all requests return the same data):

I: Polling request time: 33428ms
I: Polling request time: 35979ms
I: Polling request time: 5247ms
I: Polling request time: 28293ms
I: Polling request time: 5362ms
I: Polling request time: 5556ms
I: Polling request time: 5495ms
I: Polling request time: 27744ms
I: Polling request time: 1161ms
I: Polling request time: 34227ms
I: Polling request time: 865ms
I: Polling request time: 32169ms
I: Polling request time: 542ms
I: Polling request time: 5872ms
I: Polling request time: 641ms
I: Polling request time: 29248ms
I: Polling request time: 4756ms
I: Polling request time: 27813ms
I: Polling request time: 8048ms
I: Polling request time: 28107ms
I: Polling request time: 934ms
I: Polling request time: 29112ms
I: Polling request time: 29216ms
I: Polling request time: 5511ms
I: Polling request time: 1805ms
I: Polling request time: 33739ms
I: Polling request time: 8836ms
I: Polling request time: 1466ms
I: Polling request time: 31531ms
I: Polling request time: 30088ms
I: Polling request time: 333ms
I: Polling request time: 6271ms
I: Polling request time: 1670ms

Average time: 16.4 seconds - Maximum time: 35.9 seconds

Occasionally the requests time out.

Is this a known issue and are the response times expected to improve? Has anyone else experienced poor response times?

Thanks, Nick

Thanks for your mail and the detailed test results! This is a known issue impacting our REST API endpoint https://outlook.office365.com/api/v1.0 and a fix is on its way by end of year. A temporary workaround is to use our Preview endpoint https://outlook.office365.com/EWS/ODATA/ as this preview endpoint isn't impacted by the same issue.

Sorry again for the inconvenience and please let me know if you see the latency spikes with https://outlook.office365.com/EWS/ODATA/ as well.

Thanks, Venkat