Cron expression to plain-English + next runs API

Parse a standard 5-field cron expression (or @daily/@hourly aliases) into a plain-English description AND compute the next N fire times in any IANA timezone. Cron semantics (steps, ranges, DOM/DOW-OR) are subtle and LLMs get them wrong; this is deterministic. Answers 'what does 0 9 * * 1-5 mean', 'next 5 runs of this cron', 'explain this crontab', 'when does */15 * * * * fire'.

Price$0.01per request

MethodPOST

Route/v1/data/cron-describe

StatusLive

MIME typeapplication/json

Rate limit60/minute

CacheNo cache

datacroncrontabschedulecron-expressionnext-runtimerscheduler

API URLhttps://x402.hexl.dev/v1/data/cron-describe

Integration docs

Example request

{
  "expression": "0 9 * * 1-5",
  "count": 3,
  "timezone": "UTC",
  "from": "2026-06-01T00:00:00Z"
}

Example response

{
  "expression": "0 9 * * 1-5",
  "normalized": "0 9 * * 1-5",
  "description": "at 09:00 on Monday, Tuesday, Wednesday, Thursday, Friday.",
  "timezone": "UTC",
  "nextRuns": [
    "2026-06-01T09:00:00.000Z",
    "2026-06-02T09:00:00.000Z",
    "2026-06-03T09:00:00.000Z"
  ]
}

Input schema

{
  "type": "object",
  "required": [
    "expression"
  ],
  "properties": {
    "expression": {
      "type": "string",
      "examples": [
        "0 9 * * 1-5",
        "@hourly",
        "*/15 * * * *"
      ]
    },
    "count": {
      "type": "number",
      "examples": [
        5
      ]
    },
    "timezone": {
      "type": "string",
      "examples": [
        "America/New_York",
        "UTC"
      ]
    },
    "from": {
      "type": "string",
      "examples": [
        "2026-06-01T00:00:00Z"
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}