Logging custom or third party application usage

Question

I'm in the process of changing the name of our intranet from https://intranetA to https://intranetB. I already have both names in AAM and functioning, though nobody is using the https://intranetB address.

THere are many custom applications running as scheduled jobs that use https://intranetA, some inside console apps, interacting via API.

I'm asking the developers to update their applications/jobs/etc to use https://intranetB. Before they make changes, I want to set a trace of these jobs to verify that, pre change, they were using https://intranetA, and after change using https://intranetB.

IIS wouldn't contain these, as they're using the API. If they're in ULS, I'm not finding them discernible from oob Timer Jobs.

So how can I trace these?

Thanks!

BTW: I'm aware that I can keep the IIS and AAMs for intranetA and intranetB, and that the APIs /should/work. I do plan to keep both for the time being, but I want to be sure all custom apps are using the new alias before sending users there.