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6. Tracking



Experimentation is a primary use case for feature flags. In practice, this often means flag variants are assigned to users at random or in accordance with a business rule, while the impact of the assigned variant on some business objective is measured. Vendors and custom solutions often support a tracking or goal measuring API to facilitate the measurement of these business objectives.


  • Develop official terminology to support consistent implementation
  • Specify a flexible API widely compatible with basic vendor functionality
    • Define tracking event payload
    • Define tracking event identifier
    • Support A/B testing and experimentation use-cases
    • Support client and server paradigms
    • Provide recommendations around:
      • Async vs sync
      • Flushing mechanisms
      • Event batching


  • Creating an experimentation platform
  • Covering every user-tracking use case
    • We will not define any data aggregation mechanisms
    • We will not focus on "metrics", but instead, "facts"

Design Principles

We value the following:

  • Adherence to, and compatibility with OpenFeature semantics
  • Maximum compatibility and ease-of-adoption for existing solutions
  • Minimum traffic and payload size
  • Ease-of-use for application authors, integrators, and provider authors (in that order)