====== Integration framework Open API endpoint and documentation ======

To enable and foster external integrations with the addressing database from third party applications the national addressing system will offer a dedicated API for integrations.

===== Technical Requirements  =====

  * Database Integration
  * The API may either:
  * Reuse the existing addressing database by adding a new schema, or
  * Operate on a dedicated database instance populated from the production data model.
  * An ETL (Extract, Transform, Load) procedure must be designed and implemented to populate the integration database and keep it continuously updated with changes from the production system.
  * Technology Stack
  * The API shall be implemented in either Python (FastAPI) or .NET Core, at the vendor’s discretion.
  * The design should prioritize modularity, maintainability, and alignment with modern development best practices (e.g., OpenAPI specification, REST principles, containerization readiness).
  * Performance and Scalability
  * The API must be dimensioned to handle high traffic volumes and frequent large queries without degradation of service.
  * Performance optimization measures (e.g., indexing, caching, query tuning, load balancing) should be included.
  * The solution should support horizontal scaling if required.
  * Security and Access Control
  * Authentication and authorization must be integrated with the existing OIDC identity provider.
  * The API should support self-registration workflows, either by directly consuming the OIDC registration API or by proxying it via a custom UI.
  * Data access must comply with agreed policies on privacy, data protection, and auditability.

===== Functional Requirements  =====

The API must expose endpoints covering the following key use cases:

  * Bulk Data Access
      * Download the complete set of addressing data in structured formats suitable for third-party consumption.
  * Incremental Data Updates
      * Retrieve change sets for addressing data since a user-specified date/time.
      * Support for high-frequency incremental updates for near real-time synchronization.
  * Database Synchronization
      * Provide services to synchronize and mirror the central addressing database into decentralized instances.
      * Include retry and recovery mechanisms to ensure data consistency.
  * Search and Query Services
      * Free-text search across addressing records with relevance ranking.
      * Structured queries using address components (e.g., region, street, building).
  * Reference Data Access
      * Expose relevant code lists (e.g., administrative units, street types, address statuses) as web services.
  * Documentation and Developer Resources
      * Provide comprehensive API documentation following the Open API/Swagger standard.
      * Include tutorials, examples, and best practices for integration.
      * Contribute content for the Addressing Wiki, offering guidance for developers and integrators on how to use the API.

===== To be included in delivery  =====

  * Fully functional and tested Integration Framework API.
  * ETL scripts/procedures to maintain synchronization between production and integration databases.
  * Open API specification file and interactive API documentation (Swagger UI or equivalent).
  * Developer documentation, tutorials, and content for the Addressing Wiki.
  * Deployment guidelines and system administration documentation.
  * Security and performance testing reports.
  * An addressing integration 101 example that describes all the steps involved to create an integration with the system