How to monitor cron jobs so they don’t fail silently

I have a few scheduled jobs that run in the background. Some of them update data. Some clean things up. Some call external APIs. They are not very exciting, but when one of them stops running, it can create a surprisingly annoying problem. The worst part is that you often do not notice immediately. The job may have failed yesterday, but you only find out today because some data is missing, a report was not generated, or something looks stale. That is the kind of failure I wanted to make more vis