Date API

Any date format in. ISO, weekday, and week number out.

Pass a date the way a spreadsheet, a form, or a log wrote it. 2026-03-29, March 29, 2026, 29 Aug 2026, 3/29/2026, and 20260829 all come back as one clean answer: ISO date, weekday, ISO week, day of year, quarter, leap year, and unix time. A leading weekday and an ISO time tail are ignored.

Junk answers valid: false as a 200, never a 404. Bare GET /date answers today in UTC.

Parse

GET

api.parseapi.com/date/{date}

ISO date, weekday, ISO week, day of year, quarter, leap, unix

curl "https://api.parseapi.com/date/March%2029,%202026" \
  -H "X-API-Key: YOUR_API_KEY"

{
  "date": "2026-03-29",
  "valid": true,
  "year": 2026,
  "month": 3,
  "month_name": "March",
  "day": 29,
  "weekday": 7,
  "weekday_name": "Sunday",
  "week": 13,
  "week_year": 2026,
  "day_of_year": 88,
  "quarter": 1,
  "leap": false,
  "days_in_month": 31,
  "unix": 1774742400
}

curl "https://api.parseapi.com/date/3/29/2026" \
  -H "X-API-Key: YOUR_API_KEY"

{
  "date": "2026-03-29",
  "valid": true,
  "year": 2026,
  "month": 3,
  "month_name": "March",
  "day": 29,
  "weekday": 7,
  "weekday_name": "Sunday",
  "week": 13,
  "week_year": 2026,
  "day_of_year": 88,
  "quarter": 1,
  "leap": false,
  "days_in_month": 31,
  "unix": 1774742400
}

Response fields

date: The date as ISO YYYY-MM-DD, or the input echoed when it does not parse
valid: Resolves to one real calendar day. Ambiguous numeric dates answer false without ?format=
year: Year
month: Month, 1 to 12
month_name: English month name
day: Day of month
weekday: ISO weekday, Monday 1 to Sunday 7
weekday_name: English weekday name
week: ISO 8601 week number
week_year: The year that ISO week belongs to. Differs from year around January 1
day_of_year: Day of year, 1 to 366
quarter: Quarter, 1 to 4
leap: Whether the year is a leap year
days_in_month: Days in that month
unix: Unix time at midnight UTC of that date, seconds
to: With ?to= only: the other date, normalized ISO
days: With ?to= only: signed days from the date to ?to=. Future positive, past negative

Never a guess

3/29/2026 resolves on its own, 29 cannot be a month. 03/04/2026 could be March 4th or April 3rd, so it answers valid: false until ?format=mdy or ?format=dmy asserts a reading. Two-digit years never resolve.

curl "https://api.parseapi.com/date/03/04/2026" \
  -H "X-API-Key: YOUR_API_KEY"

{
  "date": "03/04/2026",
  "valid": false,
  "year": null,
  "month": null,
  "month_name": null,
  "day": null,
  "weekday": null,
  "weekday_name": null,
  "week": null,
  "week_year": null,
  "day_of_year": null,
  "quarter": null,
  "leap": null,
  "days_in_month": null,
  "unix": null
}

Days between

Add ?to= with another date. The response appends to, normalized ISO, and days, signed, so a past date goes negative. Bare /date?to=2026-12-25 is days until Christmas.

curl "https://api.parseapi.com/date/2026-08-29?to=2026-12-25" \
  -H "X-API-Key: YOUR_API_KEY"

{
  "date": "2026-08-29",
  "valid": true,
  "year": 2026,
  "month": 8,
  "month_name": "August",
  "day": 29,
  "weekday": 6,
  "weekday_name": "Saturday",
  "week": 35,
  "week_year": 2026,
  "day_of_year": 241,
  "quarter": 3,
  "leap": false,
  "days_in_month": 31,
  "unix": 1787961600,
  "to": "2026-12-25",
  "days": 118
}

Questions? Email