RapidSpike - RapidSpike is a reliability, performance and security monitoring service for transactional websites. Using next-generation synthetic monitoring & deeper than ever before data, RapidSpike is for businesses serious about protecting their online revenue
EasyCron - Get frustrated with Cron on your server? Hosting limits your Cron use?
Nodeping - NodePing Server Monitoring and Web Site Monitoring. Simple but powerful Internet service monitoring.
crontab guru - The quick and simple editor for cron schedule expressions by Cronitor
Webcron - Webcron - Website and Server Performance Monitoring and Online Web Cron. Reliable Cron Jobs Service with WebCron interface. The easiest way to set cron jobs.
Cronitor - Monitor cron jobs, micro-services, daemons and almost anything else, no setup required. Easier cron troubleshooting and no more silent failures.