Healthchecks.io

A fully-managed, hosted cron job and periodic task monitoring service. When any of your cron jobs or background tasks does not run at the expected time, Healthchecks detects an issue and notifies you. Healthchecks is open-source (the code is BSD licensed and available on GitHub) and can be self-hosted. Our hosted monitoring service has a generous free plan (you can monitor up to 20 jobs for free) and affordable paid plans. We offer a special discount to open-source projects and nonprofits.