Simple and effective cron job monitoring tool

I have a simple application which posts to social media sites like facebook on a schedule basis.

I slowly started realizing that all the posts are being posted twice. I initially blamed my code and spent hours figuring out the root cause but of no use.

After further investigation, I found out that the cron job which posts them to social media sites is running on two servers. This extra server is a dummy server which i started to migrate the application. But i left it behind in the middle to focus on it when i have more time. But i did not realize that the cron job is running on this server.

I immediately stopped the cron job from the dummy server. Then i thought,

what if this cron job is processing payments?

what if this cron job is generating shipment labels for e-commerce store?

what if this cron job is doing a very critical task which should not be duplicated?

I thought others might be in the same boat and realized we should start monitoring our cron jobs.

So i built CronBuzz.

CronBuzz monitors your cron jobs and alert you when your cron jobs stopped running, duplicated, or running longer than they are intended.

Are you using any kind of cron job monitoring tool? Please let me know what you think of this tool.