Cron

Parse and validate cron expressions, get human-readable explanations, compute upcoming run times, or generate expressions from natural descriptions.

POST /api/cron

Parameters

Field	Type	Required	Description
action	string	Yes	parse, explain, next_runs, or generate
expression	string	No	Cron expression — required for parse, explain, next_runs
count	integer	No	Number of next runs to compute (default 5, max 25)
timezone	string	No	IANA timezone for next_runs (e.g. America/Chicago)
every	string	No	Interval for generate: minute, hour, day, week, month
at	string	No	Time in HH:MM format (for generate with day/week/month)
weekday	string	No	Day of week (for generate with week)
day_of_month	integer	No	Day 1–31 (for generate with month)

Response

Field	Type	Description
valid	boolean	Whether the expression is valid
expression	string	The cron expression (returned by generate)
explanation	string	Human-readable description
fields	object	Parsed cron fields
fields.minute	string	Minute field
fields.hour	string	Hour field
fields.day_of_month	string	Day of month field
fields.month	string	Month field
fields.day_of_week	string	Day of week field
next_runs	array	Upcoming run times as RFC 3339 strings

Examples

Explain a cron expression

curl -X POST https://morso.dev/api/cron \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"action": "explain", "expression": "0 9 * * 1-5"}'

{
  "valid": true,
  "explanation": "At 09:00 on every day-of-week from Monday through Friday",
  "fields": {
    "minute": "0",
    "hour": "9",
    "day_of_month": "*",
    "month": "*",
    "day_of_week": "1-5"
  }
}

Get next runs

curl -X POST https://morso.dev/api/cron \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"action": "next_runs", "expression": "*/15 * * * *", "count": 3, "timezone": "Europe/London"}'

{
  "valid": true,
  "next_runs": [
    "2026-05-06T15:00:00+01:00",
    "2026-05-06T15:15:00+01:00",
    "2026-05-06T15:30:00+01:00"
  ]
}

Generate an expression

curl -X POST https://morso.dev/api/cron \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"action": "generate", "every": "week", "weekday": "monday", "at": "09:00"}'

{
  "valid": true,
  "expression": "0 9 * * 1",
  "explanation": "At 09:00 on Monday"
}

Errors

• 400 — Invalid cron expression, unknown timezone, or unsupported interval.

See Errors for the standard error shape.