api: YAML JSON TOON Database
version: 1.0.0
format: json
dataset:
  id: 1012
  slug: date-time-interchange
  title: Date and Time Interchange Patterns
  description: "Representing instants, civil dates, time zones, recurring schedules, and intervals without hidden assumptions."
  summary: "Representing instants, civil dates, time zones, recurring schedules, and intervals without hidden assumptions. Each row includes a practical application and a failure to check before using it."
  use_when[2]: Design time fields for an API or dataset.,Make a schedule keep its intended local time.
  caveats[2]: Examples do not describe leap-second support in every runtime.,Time-zone databases and runtime parsing behavior must be kept current.
  related[2]: unicode-text-handling,json-schema-keywords
  category: Programming Languages
  category_slug: programming-languages
  tags: "programming-languages,date time interchange,reference,engineering"
  view_count: 0
  created_at: 1791798640
  updated_at: 1791798640
  reviewed_at: 2026-10-12
  sources[2]{title,url}:
    RFC 3339 timestamps,"https://www.rfc-editor.org/rfc/rfc3339.html"
    IANA time-zone database,"https://www.iana.org/time-zones"
  reading[1]: timestamps-time-zones-and-half-open-intervals
  provenance: "Original editorial reference notes by YJTOON, informed by the linked primary documentation. External specifications retain their own licenses."
  entry_count: 10
  fields[4]{section,field,type,example}:
    data,case,string,UTC instant
    data,example,string,"2026-10-12T09:00:00Z"
    data,representation,string,RFC 3339 timestamp with an explicit UTC offset.
    data,trap,string,A local-looking timestamp without an offset is …
data[10]{case,example,representation,trap}:
  UTC instant,"2026-10-12T09:00:00Z",RFC 3339 timestamp with an explicit UTC offset.,A local-looking timestamp without an offset is ambiguous.
  Offset instant,"2026-10-12T12:00:00+03:00",Timestamp identifying the same instant with a numeric offset.,An offset is not a geographic time-zone rule set.
  Civil date,2026-10-12,Calendar date without a time.,Converting a birthday to UTC can change the displayed date.
  Named time zone,Europe/Istanbul,IANA time-zone identifier for local scheduling.,Government rules can change; update the time-zone database.
  Recurring appointment,"09:00 every Monday in Europe/Istanbul",Local rule plus named zone and recurrence.,A fixed UTC time may shift the intended local hour.
  Unix seconds,"1791795600",Integer count of seconds from the Unix epoch.,Do not confuse seconds with milliseconds.
  Unix milliseconds,"1791795600000",Integer count at millisecond scale.,Declare the unit in the field name or schema.
  Fractional precision,"2026-10-12T09:00:00.123Z",Explicit fraction of a second.,Consumers may round or truncate to lower precision.
  Half-open interval,start <= event_time AND event_time < end,Include the start and exclude the end.,Adjacent windows double-count a shared end if both are closed.
  Monotonic elapsed time,performance.now() difference in a browser,Measure durations with a monotonic clock.,Wall-clock adjustments can distort elapsed-time measurements.