ISO, spelled months in both orders (March 29, 2026 and 29 Aug 2026), numeric like 3/29/2026, and compact 20260829. A leading weekday and an ISO time tail are ignored.

What about 03/04/2026?

March 4th or April 3rd, both are real days, so it answers valid: false. Pass format=mdy or format=dmy to assert a reading. 3/29/2026 resolves on its own, since 29 cannot be a month. We never guess.

How do I count days between dates?

Add to=. /date/2026-08-29?to=2026-12-25 appends to and days: 118. Signed, so a past date goes negative. Bare /date?to= counts from today.

What week numbering is this?

ISO 8601. Weeks start Monday, and week_year names the year the week belongs to, which differs from year around January 1.

Anything that does not resolve to one real calendar day, including two-digit years. Junk answers valid: false as a 200, never a 404.

GET /date/{date}

Date API

Pass a date any way it was written. Get one clean answer.

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=

weekday_name

English weekday name

week

ISO 8601 week number

day_of_year

Day of year, 1 to 366

quarter

Quarter, 1 to 4

leap

Whether the year is a leap year

unix

Unix time at midnight UTC of that date, seconds

Pass the mess

March 29, 2026, 3/29/2026, 29 Aug 2026, or 20260829. A weekday and a time tail are ignored.

Get the facts

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

Ambiguity answers false

03/04/2026 is two real days. Without ?format= it answers valid: false, never a guess.

Never a guess.

Days between dates with ?to=. Every plan.

ISO 8601
week numbering: 0
guessed readings

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

We never guess a reading. 3/29/2026 resolves on its own, since 29 cannot be a month. 03/04/2026 could be two real days, so it answers valid: false until you pass ?format=mdy or ?format=dmy. Add ?to= for the signed days between two dates, and bare /date?to= counts from today.

RESPONSE

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

// 200 · ~27ms US · ~122ms worldwide
{
  "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

QUESTIONS

What formats parse?: ISO, spelled months in both orders (March 29, 2026 and 29 Aug 2026), numeric like 3/29/2026, and compact 20260829. A leading weekday and an ISO time tail are ignored.
What about 03/04/2026?: March 4th or April 3rd, both are real days, so it answers valid: false. Pass format=mdy or format=dmy to assert a reading. 3/29/2026 resolves on its own, since 29 cannot be a month. We never guess.
How do I count days between dates?: Add to=. /date/2026-08-29?to=2026-12-25 appends to and days: 118. Signed, so a past date goes negative. Bare /date?to= counts from today.
What week numbering is this?: ISO 8601. Weeks start Monday, and week_year names the year the week belongs to, which differs from year around January 1.
What counts as junk?: Anything that does not resolve to one real calendar day, including two-digit years. Junk answers valid: false as a 200, never a 404.

SPEED

How long a lookup takes.

27ms

50ms

APAC

144ms

LatAm

21ms

122ms

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