PagerDuty's Events API V2 lets you push events from your monitoring systems to PagerDuty. You can push such events when there is a triggered, updated, or resolved incident.
Why should you monitor your third-party Cloud and SaaS vendors if you are in SRE/Ops? As part of an SRE team, your primary responsibility is ensuring the reliability of your applications. What makes you responsible for monitoring services that you don't even manage? Third-party services are just like yours - with SLAs. And outages happen, affecting you as well as many others who depend on them.
How many monitoring tools do you have? Chances are at least 2-3. One tool usually does not cover all cases, and it’s usually a combination of self-managed and managed tools. Self-managed gives you more control over custom configurations and cost. Managed ones take away the headache of running it yourself. Prometheus is the de-facto standard for monitoring these days if you have a modern application stack and you want to manage your own monitoring.
If you have a software-based business, you are using at least a few cloud based tools. It does not matter if you are a solo developer, or part of a 50-member team in a large organization. Take this random list and chances are you are using at least half of them: Your entire business - irrespective of org or market size - including your development tools, collaboration/communication tools, infrastructure and hosting, monitoring, even email - is dependent on services that you don’t control.