{
  "answer": "2026-10-19 is a Monday (ISO week 2026-W43, day 292 of the year). 2026-10-19 plus 90d is Sunday 2027-01-17.",
  "date": "2026-10-19",
  "weekday": "Monday",
  "iso_week": "2026-W43",
  "day_of_year": 292,
  "leap_year": false,
  "days_in_month": 31,
  "add": {
    "duration": "90d",
    "result": {
      "date": "2027-01-17",
      "weekday": "Sunday",
      "iso_week": "2027-W02",
      "day_of_year": 17,
      "leap_year": false,
      "days_in_month": 31
    },
    "month_end_clamped": false
  },
  "calendar": "proleptic Gregorian, UTC dates",
  "deterministic": true,
  "docs": "https://bozos.si/tools/fetch#date"
}