API Date Ranges: start_date, end_date and UTC | Genezio

This page explains how the Genezio API reads a date range. Each report reads one range of dates, with start_date and end_date.

The rules of a date range

A date is YYYY-MM-DD, or a datetime of ISO 8601 such as 2026-09-01T08:00:00Z.
A date is a day in UTC.
Both ends are inclusive. An end_date of 2026-09-30 covers that whole day, up to 23:59:59.999999 UTC.
A datetime with no time zone is in UTC.
With no start_date, the range starts 30 days before its end.
With no end_date, the range ends now.
A range holds at most 366 days.

Examples of date ranges

You send	The API reads
`start_date=2026-09-01&end_date=2026-09-30`	The whole of September, in UTC.
`start_date=2026-09-01T08:00:00&end_date=2026-09-01T17:00:00`	From 08:00 to 17:00 UTC on 1 September.
`start_date=2026-09-01T08:00:00+02:00`	From 06:00 UTC.
No dates	The last 30 days.

info.query gives the range that the API read, with each end as a full datetime:

"query": {
  "start_date": "2026-09-01T00:00:00+00:00",
  "end_date": "2026-09-30T23:59:59.999999+00:00"
}

Periods and granularity

A report with granularity divides the range into periods:

Granularity	A period starts on
`day`	Each day.
`week`	Each Monday.
`month`	The first day of each month.

The date of a row is the first day of its period. The first and the last period can be partial: a range that starts on a Wednesday gives a first week that starts on the Monday before it.

A range that ends now gives a last period that is not complete. Compare the last period with care, or end the range at the last complete period.