About cronhelp.me

cronhelp.me is a free, client-side toolkit for working with cron expressions. It explains an expression in plain language, previews the next runs in your own time zone alongside the schedule's, and — the part no other tool does — lints for the well-known cron foot-guns: the day-of-month / day-of-week OR trap, daylight-saving hazards, impossible dates, step misconceptions and more.

Everything runs in your browser. No expression is sent anywhere, there are no accounts, and the whole site is statically generated, so it works offline once loaded and costs nothing to run. That is deliberate: the goal is a fast, honest reference you can link to in a pull request or paste into a search bar, not a funnel for a paid product.

The linter is open source. It ships as cronlint, a zero-dependency npm package with a command-line interface and a language-neutral conformance suite, so the rules can be ported to other languages without drifting. If you want to run the same checks in CI, that package is the place to start.