TL;DR Want to monitor your websites or get notified when your cron jobs or scheduled tasks are not running when they are supposed to run? Check out https://allgood.systems.
For quite some time I was planning to build some piece of software that notifies me when a web app goes down, returns unexpected results, or changes content. In addition – since it’s often hard to keep track of all the background jobs that are running – I needed and wanted something that informs me when my services stop (!) doing what they are supposed to do in regular intervals (which is often detected much later and in turns makes recovery/clean-up much harder).
While I was thinking through the problem I also noticed how frequently in the past I received reports about applications that apparently stopped working from one day to the other. Often the reason turned out to be that someone forgot to renew a TLS certificate and no automated renewal was set up (while automation is generally better, often it’s just not done or you are not in control). So getting notifications about upcoming SSL certificate expirations was another thing that fit into the scope of the project.
Finally, I wanted a service which could quickly give me a private HTTP endpoint and alert me instantly whenever it received any request – for example to get informed about rare events, check when some page or file is opened, test for vulnerabilities, etc.
With this concrete need and a desire to learn a couple of new technologies along the way, I built a service that now addresses the above use cases. If you like to try out an early version of it, feel free to head over to https://allgood.systems and sign-up. With some limitations you can use it free of charge. For usage examples, please also see the documentation.