I still work on it two hours per workday, before my day job starts, but it now supports uptime monitoring for websites, APIs and JavaScript apps, as well as cron job/scheduled task monitoring, and has built-in status pages (https://hackernews.onlineornot.com for example).
It's been funny working in a "red ocean" (as MBA-types call it), competitors will enter the market with such enthusiasm, and close up shop a few months later when they haven't made nearly enough money to justify the effort.
Anyway, I'm a big fan of the "outlast" strategy as described by Justin Duke (of Buttondown): https://www.applied-cartography.com/goon-squad - my aim is to ship high quality code over a very long time, and the business seems to be growing faster and faster each year, so it seems to be working.