The Cape Sensor supports two types of Slack service (API) tests, in addition to the HTTP GET, TCP, and ICMP ping tests.
To test actual indicative performance of the Slack chat application we offer the web API and real-time messaging (RTM) API tests.
This is a basic test that doesn't require any additional setup or tokens. This tests if the sensor is able to access the Web API, and it measures the elapsed time from making a request to the API, until receiving a response.
This is the actual test for measuring Slack messaging performance, and it requires additional setup by you. The initial connection timing will be similar to the Web API timing, but once this connection is established, it is maintained (WebSocket) and subsequent communication over it is quicker.
After the connection is established, we measure elapsed time from sending a ping message to receiving a corresponding pong reply. The connection time is not graphed.
Read more here about setting up the RTM API test: https://help.capenetworks.com/testing/creating-a-slack-api-token