Use metrics APIs for cron-job, API-failure, and business-event charts, then add a separate heartbeat monitor for jobs that never start.
That is the smallest stack I would put on call for a small SaaS. A metrics dashboard can show success and failure counts, duration, backlog size, and error-rate trends; it cannot prove that a scheduler actually invoked a job. Healthchecks-style monitoring closes that specific gap. It still isn't full monitoring coverage, and I wouldn't describe it that way in an SLO review.
The distinction matters because a failed run and a missing run leave different evidence. An API error usually increments something. A business event can be counted. A cron job that never fires may produce nothing at all — no duration, no failure, no final log line. No signal.
How should a backend metrics dashboard combine cron jobs, API failures, and healthchecks?
Start with the questions an operator must answer, not with a vendor menu. For cron jobs, I want a success count, a failure count, duration, and any queue backlog that can delay completion. For API failures, I want error counts and an error-rate trend beside request volume, because a raw count without a denominator can make ordinary traffic growth look like a regression. For business events, I want domain verbs: invoices issued, imports completed, or messages accepted. Those widgets belong on one dashboard because they describe the same service from different angles.
