API for the Exchange of Medicinal Product Information (APIX), published by HL7 International / Biomedical Research and Regulation. This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/APIX---API-Exchange-for-Medicinal-Products/ and changes regularly. See the Directory of published versions

Subscription

Page standards status: Informative

Subscription

In APIX, the Subscription resource is the mechanism that delivers real‑time notifications when regulatory events occur. A Subscription becomes active when:

1. The event matches the trigger defined in the SubscriptionTopic, and
2. The resource involved satisfies the Subscription.filterBy constraints.

When both conditions are met, the server sends a notification bundle to the subscriber’s configured Subscription.endpoint.

APIX uses Subscriptions for two primary regulatory event types:

• Task Status Change — filtered by Task.identifier
  Notifies the requester when the regulator updates the status of a Task (e.g., received → accepted, in‑progress → on‑hold, completed).

• Task Creation — filtered by Task.owner
  Notifies an Organization when the regulator creates a new Task for them (e.g., questions, decision letters, follow‑up actions).

These two patterns allow APIX participants to receive immediate, event‑driven updates without polling.

Example Subscription

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Key Elements of the APIX Subscription Resource

Element	Cardinality (APIX)	Value / Example	Purpose / Notes
Subscription.filterBy	0..*	• filterParameter = identifier or owner • value = e.g. Organization/1001	Defines the subset of events the subscriber is interested in (e.g., Tasks for a specific organization or Tasks with a specific identifier)
Subscription.topic	1..1	Canonical URL of the SubscriptionTopic e.g. http://myfhir/fhir/SubscriptionTopic/TaskStatusChangeWithIdentifierFilter	Must exactly match the SubscriptionTopic.url that governs the event type and trigger logic
Subscription.endpoint	1..1	REST‑hook endpoint URL e.g. https://hapi.requestcatcher.com/	Destination where event notifications are delivered
Subscription.reason	1..1	Human‑readable explanation e.g. “Notify Organization when a new Task is assigned”	Describes the business purpose for auditability and transparency
Subscription.managingEntity	0..1	Reference(Organization) e.g. Organization/1001	Identifies the organization responsible for maintaining the subscription