RapidSpike - RapidSpike is an uptime and performance monitoring service for websites and web applications.
Healthchecks.io - Monitor your cron jobs and scheduled tasks, get notified when they fail.
Monitis - Monitis specializes in IT monitoring, covering server, website, app monitoring and more within an all-in-one monitoring platform.
Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.
Raygun - Raygun gives developers meaningful insights into problems affecting their applications. Discover issues - Understand the problem - Fix things faster.
PushMon - PushMon is a new kind of cloud-based monitoring system.