Emittedin

Emittedin is a term used in some discussions of event-driven design to describe the scope or context in which an event is emitted. It is not a formal standard, but a conceptual label intended to help distinguish where and by whom an event originates within a system, such as a module, service boundary, transaction, or user session.

Etymology and concept: The word combines emitted and in to signal the emission context. In practice, emittedin may appear as metadata attached to events, as a trait on the event payload, or as a naming convention within an event schema. The idea is to make the emission origin explicit so downstream components can reason about routing, filtering, and observability.

Usage and patterns: Emittedin is often leveraged to aid event routing, access control, and observability. Consumers can decide whether to react to events based on their emittedin value, enabling localized handling, scoped auditing, or cross-service tracing. It can also help surface scope-related issues during debugging and testing.

Implementation considerations: In code, an event might carry an emittedIn field or tag, such as { type, data, emittedIn: 'inventory-service' }. Some teams prefer a hierarchical or namespaced approach (e.g., 'domain.inventory'). However, adding emittedin data introduces overhead and potential sensitivity of internal boundaries, so privacy and performance implications should be weighed.

Relation to other concepts: Emittedin relates to topics like tracing, correlation IDs, and context propagation, but focuses specifically on the emission scope rather than transfer context alone.

See also: event-driven architecture, event schema, logging and observability, tracing. Note that emittedin remains a community-driven concept rather than a widely standardized term.