You can use health endpoint as described on API entities page.
For production usage you can use browser or curl HTTP request:
https://his.hidglobal.com/ais/v1/tenant/root/health
or
curl https://his.hidglobal.com/ais/v1/tenant/root/health
Service will return following reply when online: Healthy
This healthcheck can be easily integrated to other health monitoring services.