[{"data":1,"prerenderedAt":98},["ShallowReactive",2],{"tool-guide:cron-builder":3},{"overview":4,"whatIs":5,"useCases":6,"steps":12,"commonMistakes":17,"relatedStandards":23,"comparison":36,"example":75,"limitations":79,"faq":82},"Cron Schedule Builder assembles and validates conventional five-field Unix cron expressions and translates them into a readable schedule summary.","A cron expression is a compact string that defines a recurring schedule. It originated in Unix cron, the time-based job scheduler present on every Linux and macOS system since the 1970s. The standard format uses five fields separated by spaces: minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC), and day of week (0-6 or SUN-SAT, where 0 is Sunday). Each field can be a specific value, a range (1-5), a list (1,3,5), a step (*\u002F15 means every 15th value), or an asterisk (every value). Cron expressions are now used far beyond Unix: Kubernetes CronJobs, GitHub Actions schedules, AWS EventBridge rules, Airflow DAGs, and CI\u002FCD pipelines all use cron syntax to trigger jobs. Despite its ubiquity, cron syntax is notoriously easy to get wrong — a misplaced field can schedule a job hourly instead of daily, or fire on the wrong day of the week. A cron builder tool lets you construct the expression visually and immediately see the human-readable schedule it produces, catching mistakes before they reach production.",[7,8,9,10,11],"Scheduling CI\u002FCD pipelines — build the cron expression for a nightly build, weekly dependency audit, or end-of-month report before pasting it into your GitHub Actions or GitLab CI config.","Configuring Kubernetes CronJobs — write the schedule for a database backup, log rotation, or health check that runs at specific business hours or maintenance windows.","Setting up monitoring alerts — define when periodic checks should run (e.g., every 5 minutes during business hours, hourly on weekends).","Planning batch processing — schedule ETL jobs, data syncs, or email digests at times that avoid peak traffic.","Debugging existing schedules — paste a cron expression from an existing config file to verify that it fires when you expect it to.",[13,14,15,16],"Use the visual picker to select values for each field: minute, hour, day of month, month, and day of week.","Alternatively, type a raw cron expression directly and the builder parses and validates it.","Read the human-readable schedule summary to confirm the expression matches your intent.","Copy the expression into your scheduler config. Remember that the timezone is determined by the scheduler, not the expression.",[18,19,20,21,22],"Confusing field order — the five fields are minute, hour, day, month, weekday. A common mistake is putting the hour first (as in everyday language) instead of the minute.","Forgetting that 0 is Sunday — in standard Unix cron, day-of-week 0 is Sunday and 6 is Saturday. Some systems (like Quartz) use 1 for Sunday.","Using Quartz syntax in Unix cron — Quartz adds a seconds field (6-7 fields total) and uses different day-of-week numbering. A Quartz expression will misfire in Unix cron.","Ignoring timezone — cron expressions have no timezone. The scheduler (crontab, Kubernetes, AWS) determines which timezone the schedule runs in. Always verify the timezone setting.","Overlapping day-of-month and day-of-week — in standard cron, if both fields are set (not *), the job runs when either condition matches (OR logic), not both (AND logic). This surprises most users.",[24,27,30,33],{"title":25,"url":26},"crontab(5) — Linux man page","https:\u002F\u002Fman7.org\u002Flinux\u002Fman-pages\u002Fman5\u002Fcrontab.5.html",{"title":28,"url":29},"Kubernetes CronJob documentation","https:\u002F\u002Fkubernetes.io\u002Fdocs\u002Fconcepts\u002Fworkloads\u002Fcontrollers\u002Fcron-jobs\u002F",{"title":31,"url":32},"GitHub Actions — on.schedule syntax","https:\u002F\u002Fdocs.github.com\u002Fen\u002Factions\u002Fusing-workflows\u002Fevents-that-trigger-workflows#schedule",{"title":34,"url":35},"AWS EventBridge — Cron expressions","https:\u002F\u002Fdocs.aws.amazon.com\u002Feventbridge\u002Flatest\u002Fuserguide\u002Feb-cron-expressions.html",{"heading":37,"columns":38,"rows":43},"Cron syntax across platforms",[39,40,41,42],"Unix cron","Kubernetes","GitHub Actions","AWS EventBridge",[44,49,53,57,62,69],{"label":45,"values":46},"Fields",[47,47,47,48],"5 (min-wday)","6 (min-year)",{"label":50,"values":51},"Seconds field",[52,52,52,52],"No",{"label":54,"values":55},"Year field",[52,52,52,56],"Yes (optional)",{"label":58,"values":59},"Sunday",[60,60,60,61],"0 or 7","1",{"label":63,"values":64},"Timezone",[65,66,67,68],"System TZ","Pod TZ (UTC default)","UTC only","UTC (configurable)",{"label":70,"values":71},"Day logic",[72,73,73,74],"OR (day\u002Fwday)","OR","AND",{"label":76,"input":77,"output":78},"Weekdays at 08:30","30 8 * * 1-5","At 08:30 on every weekday.",[80,81],"The tool targets five-field Unix cron, not Quartz seconds\u002Fyear extensions.","Timezone and daylight-saving behavior belong to the scheduler that executes the expression.",[83,86,89,92,95],{"question":84,"answer":85},"What are the five fields in a cron expression?","Minute (0-59), hour (0-23), day of month (1-31), month (1-12), and day of week (0-6, Sunday=0). Asterisks mean \"every value.\"",{"question":87,"answer":88},"Does this support Quartz or AWS cron syntax?","No. This tool targets the standard five-field Unix cron format. Quartz (six or seven fields with seconds and years) and AWS (six fields) are not supported.",{"question":90,"answer":91},"What timezone does the schedule use?","The tool shows the expression and its meaning but does not determine the timezone. The scheduler that runs the job (crontab, Kubernetes, GitHub Actions) controls the timezone.",{"question":93,"answer":94},"What does *\u002F5 mean?","The step syntax *\u002F5 means \"every 5th value.\" In the minute field, *\u002F5 fires at minutes 0, 5, 10, 15, ..., 55.",{"question":96,"answer":97},"How do I schedule a job for the last day of the month?","Standard cron has no \"last day\" syntax. Common workarounds include scheduling on the 28th (misses some months), using a wrapper script that checks the date, or using a scheduler that supports L syntax (like Quartz).",1788868140178]