Timestamps

Read and send UDX timestamps in RFC 3339 form, with UTC responses and microsecond precision.

Every UDX timestamp is an RFC 3339 string. Fields that hold an instant end in _at; query parameters that bound an instant end in _after or _before, and both bounds are exclusive.

Responses

Responses use UTC with exactly six fractional digits:

2026-06-21T00:00:00.000000Z

Requests

A timestamp in a request must carry an explicit UTC offset and may use zero to six fractional digits. These are all accepted and name the same instant:

2026-01-01T00:00:00Z
2026-01-01T00:00:00.5Z
2025-12-31T19:00:00.000000-05:00

A value without an offset, or with more than six fractional digits, returns 400.

Request signing uses a different clock format: the timestamp header must be Unix time in milliseconds.