Tick

Use when you or the user just wrote a cron expression (GitHub Actions, Vercel cron, Cloudflare Cron Triggers, systemd, an agent schedule) and need the next fire times before claiming it is correct. Pass the expression and an IANA timezone (default UTC). Returns the next N runs as local wall times and UTC ISO, a plain-English field breakdown, and DST gap/fold warnings (spring-forward skips, fall-back double fires). Example: {"expression":"0 9 * * 1-5","timezone":"America/New_York","count":5}. Do not guess next runs yourself — DST rules differ by region and year. Not for converting a meeting time across cities (use Meridian) or for email DNS (use Stamp).

Use when you need a yes/no on whether a cron expression would fire at a specific instant in a timezone — for example before shipping a schedule that crosses a DST transition, or to verify a single expected fire. Example: {"expression":"0 9 * * 1-5","timezone":"America/New_York","at":"2026-11-06T14:00:00Z"}. Returns fires true/false, the local wall time of that instant, and DST notes if the local time is in a gap or fold.