The problem
Cron syntax is notoriously hard to verify — developers copy expressions from Stack Overflow or write their own, then paste them into random online parsers to check them, often without offline access or confidence in edge-case handling.
If you've hit this before, you know how it goes — you fire up a browser tab, paste the expression into crontab.guru, and hope it interprets edge cases the same way your cron daemon does.
As a solution, I created croncheck
Parse and preview cron expressions interactively — see the next 10 run times before you deploy
