Enables to set up a probe that monitors HTTP request for example. Prometheus itself can't do API endpoint monitoring - it can only ask results from probes.

https://github.com/prometheus/blackbox_exporter

You can just download the binary and run it on your server. It will be available on a configured port. In the blackbox directory is blackbox.yml file with configurations of different monitoring options. The URL's to be monitor can be configured into there, but can also be given by Prometheus in the URL when it pings the probe.

Here is quite an extensive example of different configuration options: https://github.com/prometheus/blackbox_exporter/blob/master/example.yml

Output of the probe is quite extensive, but main parameters to look for: probe_http_status_code probe_success

Links: All Blackbox configuration options: https://github.com/prometheus/blackbox_exporter/blob/master/CONFIGURATION.md https://blog.ruanbekker.com/blog/2019/05/17/install-blackbox-exporter-to-monitor-websites-with-prometheus/ https://www.sethryder.com/blackbox-exporter-accessing-multiple-modules-and-targets-with-a-single-job/