Type or paste a 5-field cron expression below, or use a preset — the explanation updates live. Runs entirely in your browser.
* means "every value"; */N means "every N units"; A-B is a range; A-B/N is a stepped range; A,B,C is a list — these can combine, e.g. 1-5,10-15/2.curl -sS "https://devops.majbase.com/cron-builder/api" \
--data-urlencode 'cron=0 9 * * 1-5' \
--data-urlencode 'count=5'
Returns JSON: {"summary": "..."|null, "breakdown": {"minute": "...", "hour": "...", "dayOfMonth": "...", "month": "...", "dayOfWeek": "..."}, "next_runs": ["2026-08-17T09:00:00", ...]}, or {"error": "..."} for a malformed expression. count is optional (default 5, max 20); next_runs times are in the server's local time zone, starting from now.
Want an AI agent (Claude Code, claude.ai, or anything else that supports the Agent Skills format) to use this tool for you on request? Download the skill below and add it:
~/.claude/skills/cron-builder/SKILL.md