Datadog's Synthetic Monitoring correlates API and browser tests into APM traces, logs and infrastructure metrics, run from managed locations or inside your own network — useful depth if your stack already lives in Datadog, and overkill if it doesn't.
Synthetics is billed by usage — roughly $5 per 10,000 API runs and $12 per 1,000 browser runs — and cost multiplies across tests × locations × frequency. There's no free synthetics tier, no built-in status page (that lives in a separate Incident Management product), and no heartbeat checks for silent cron jobs. 247Monitor prices the opposite way: flat plans from £9, browser journeys and a status page included, every cron job watched.