CALENDAR
Leap Year API
/leap-yearCheck whether a given year is a Gregorian leap year.
No signup or API key required.
Parameters
yearintegeroptional · query- Gregorian year to check, from 1 to 9999. Defaults to the current UTC year.
formatenumoptional · query- Response format. Defaults to json.
jsontext
No request body. Unknown or repeated query parameters return HTTP 400.
Returns 200 OK
A JSON object with the following fields.
yearinteger- The supplied year or current UTC year.
leapboolean- Whether this is a Gregorian leap year, including century exceptions.
Plain text
With format=text: Only true or false, without the year.
Errors
Validation and service errors always return JSON, including when format=text.
errorstring- A machine-readable error code, such as invalid_parameter or rate_limited.
messagestring- A description of the problem.
400 Invalid parameters.
414 Query string exceeds 2048 characters.
429 Rate limit reached. Wait the seconds in Retry-After before retrying.
Usage notes
Optional year: integer 1..9999, default current UTC year. Gregorian leap-year rule including century exceptions. Text returns the boolean.
Validate a calendar example or explain February’s extra day. Supply year to check a specific year, or omit it to use the current UTC year.
Responses are not cached. Browser requests are supported through open CORS.
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