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:
    - Design time fields for an API or dataset.
    - Make a schedule keep its intended local time.
  caveats:
    - Examples do not describe leap-second support in every runtime.
    - Time-zone databases and runtime parsing behavior must be kept current.
  related:
    - 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:
    - title: RFC 3339 timestamps
      url: "https://www.rfc-editor.org/rfc/rfc3339.html"
    - title: IANA time-zone database
      url: "https://www.iana.org/time-zones"
  reading:
    - 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:
    - section: data
      field: case
      type: string
      example: UTC instant
    - section: data
      field: example
      type: string
      example: "2026-10-12T09:00:00Z"
    - section: data
      field: representation
      type: string
      example: RFC 3339 timestamp with an explicit UTC offset.
    - section: data
      field: trap
      type: string
      example: A local-looking timestamp without an offset is …
data:
  - case: UTC instant
    example: "2026-10-12T09:00:00Z"
    representation: RFC 3339 timestamp with an explicit UTC offset.
    trap: A local-looking timestamp without an offset is ambiguous.
  - case: Offset instant
    example: "2026-10-12T12:00:00+03:00"
    representation: Timestamp identifying the same instant with a numeric offset.
    trap: An offset is not a geographic time-zone rule set.
  - case: Civil date
    example: "2026-10-12"
    representation: Calendar date without a time.
    trap: Converting a birthday to UTC can change the displayed date.
  - case: Named time zone
    example: Europe/Istanbul
    representation: IANA time-zone identifier for local scheduling.
    trap: Government rules can change; update the time-zone database.
  - case: Recurring appointment
    example: "09:00 every Monday in Europe/Istanbul"
    representation: Local rule plus named zone and recurrence.
    trap: A fixed UTC time may shift the intended local hour.
  - case: Unix seconds
    example: "1791795600"
    representation: Integer count of seconds from the Unix epoch.
    trap: Do not confuse seconds with milliseconds.
  - case: Unix milliseconds
    example: "1791795600000"
    representation: Integer count at millisecond scale.
    trap: Declare the unit in the field name or schema.
  - case: Fractional precision
    example: "2026-10-12T09:00:00.123Z"
    representation: Explicit fraction of a second.
    trap: Consumers may round or truncate to lower precision.
  - case: Half-open interval
    example: start <= event_time AND event_time < end
    representation: Include the start and exclude the end.
    trap: Adjacent windows double-count a shared end if both are closed.
  - case: Monotonic elapsed time
    example: performance.now() difference in a browser
    representation: Measure durations with a monotonic clock.
    trap: Wall-clock adjustments can distort elapsed-time measurements.