I looked through the API reference and didn’t see a method to get the status of the Orchestrator site. However, you could use one of the other methods to check the availability. I thought the Authentication method would be a good place to start. This link will take you to the example for making an authentication request using the Orchestrator API. The other methods are in this reference guide so you could find another method that meets your needs better.
The endpoint you mentioned would just monitor the Orchestrator health.
How could we monitor the state of each robot via a 3rd party application? This should be without using any authentication. If I use authentication, it makes it 2 API calls (version 2018.4) and we need it to be possible via a single API call.
It’s good suggestion, however not helpful in our case. We monitor Health Check from 3rd party application, so it’s the 3rd party application hitting UiPath Orchestrator endpoint, not the other way round.