The operations guy is here. I'm probably biased. If I were you, I would use free monitoring services like uptimerobot. There are some other options available.

The operations guy is here. I'm probably biased. If I were you, I would use free monitoring services like uptimerobot. There are some other options available. Typically these services provide some basic functionality for free, it would be enough for a small enterprise. On AWS it is quite easy to create your own external probes for a reasonable price. However, it would require some basic programming skills.