Time

Payload timestamps should advance with simulated traffic, not with documentation rendering or connector delay. Time functions use the scenario event clock.

The result

The one-second generator interval advances now() while the fixed promised date stays unchanged:

{"createdAt":"2026-01-02T03:04:05Z","day":"2026-01-02","displayTime":"2026-01-02T03:04:05Z","promisedDate":"2026-01-10"}
{"createdAt":"2026-01-02T03:04:06Z","day":"2026-01-02","displayTime":"2026-01-02T03:04:06Z","promisedDate":"2026-01-10"}

Generate order times

defaults:
  seed: 42
  clock:
    start: 2026-01-02T03:04:05Z
generators:
  - name: orders
    config:
      interval: 1s
      maxEvents: 2
    value:
      createdAt: =now()
      day: =now(format=yyyy-MM-dd)
      displayTime: =formatDateTime(now(), format=RFC3339)
      promisedDate: =date(2026-01-10, 2026-01-10)

With a fixed defaults.clock.start, timestamps are reproducible. Without one, a run starts its scenario clock from the current time.

now(format?, timezone?)

Returns the current scenario event time.

Bare now() returns a timestamp value, which JSON encodes in RFC 3339 form with up to nanosecond precision. Pass format to return a formatted string.

createdAt: =now()
day: =now(format=yyyy-MM-dd)
stamp: =now(format=RFC3339)
millis: =now(format=RFC3339Milli)
hourMinute: =now(format=yyyy-MM-dd:HH-mm)
localDay: =now(format=yyyy-MM-dd, timezone=UTC)

With defaults.clock.start: 2026-01-02T03:04:05Z:

{"createdAt":"2026-01-02T03:04:05Z","day":"2026-01-02","stamp":"2026-01-02T03:04:05Z","millis":"2026-01-02T03:04:05.000Z","hourMinute":"2026-01-02:03-04","localDay":"2026-01-02"}

Named layouts are RFC3339, RFC3339Milli, RFC3339Nano, RFC1123, and RFC1123Z. Pattern tokens include yyyy, MM, dd, HH, mm, ss, and SSS. timezone must be an IANA timezone and is only valid when format is present.

date(start, end)

Returns a yyyy-MM-dd string selected between two inclusive dates.

birthDate: =date(1970-01-01, 2000-12-31)

{"birthDate":"1970-05-29"}

end must be the same as or later than start.

datetime(start, end)

Returns a UTC timestamp selected from the inclusive interval.

occurredAt: =datetime(2026-01-01T00:00:00Z, 2026-01-02T00:00:00Z)

{"occurredAt":"2026-01-01T12:03:03.676623051Z"}

Both arguments must be date-time values, and end must not be earlier than start.

formatDateTime(value, format, timezone?)

Formats an existing date-time value with the same patterns, layouts, and timezone rules as now.

day: =formatDateTime(now(), format=yyyy-MM-dd, timezone=UTC)
stamp: =formatDateTime($createdAt, format=RFC3339Milli)

With createdAt: =now() and defaults.clock.start: 2026-01-02T03:04:05Z:

{"day":"2026-01-02","stamp":"2026-01-02T03:04:05.000Z"}

Use now(format=...) when formatting the current event time directly. Use formatDateTime for a value from a field, variable, or another time function.

Clock start and pacing are explained in Time and pace. For duration strings rather than timestamps, use uniformDuration.

Next: format strings and read environment values.