title: fragment/analytics/app_identifiers
description: >
  Standard identifiers for Wikimedia product/feature analytics in mobile apps
  which use an implementation of the Event Platform Client (EPC) specification.
$id: /fragment/analytics/app_identifiers/1.0.0
$schema: 'https://json-schema.org/draft-07/schema#'
type: object
properties:
  app_install_id:
    description: >
      Identifies an install of the app and persists across all sessions. When
      the user uninstalls the app and re-installs it, a new app install ID is
      randomly generated.

      This UUIDv4 identifier is assigned automatically by the EPC library in the
      the Wikipedia app for Android and iOS.
    type: string
    maxLength: 36
    minLength: 36
    pattern: >-
      ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$
  app_session_id:
    description: >
      Identifies an app session: a cluster of actions taken by the user in the
      app within a limited period of time. A session ID is generated the first
      time it is requested by the instrumentation code, which will usually be
      soon after the user launches the app. A new session ID is generated
      anytime the app has been inactive (that is, in the background state) for
      at least 15 minutes or has been forcibly stopped by the OS or the user.

      This identifier is managed and assigned automatically by the EPC library
      in the Wikipedia app for Android and iOS.
    type: string
    maxLength: 20
    minLength: 20
    pattern: '^[0-9a-z]{20}$'
examples:
  - app_install_id: 33333333-3333-3333-3333-333333333333
    app_session_id: '55555555555555555555'