Atomic Parameter List

_{Published: 22 April 2025}

Known Use

• CloudEvents: CloudEvents is a vendor-neutral specification for defining the format of event metadata. Since nesting is not recommended, its context attribute envelope serves as an flat Atomic Parameter List. For more details, see CloudEvents in the Dutch Energy Sector.
• Pagination Metadata: In many API implementations, pagination metadata is structured in one of two ways:
  • As an Atomic Parameter List, where individual pagination attributes (e.g., currentPage, pageSize, offset, totalRecords, totalPages) are returned separately;
  • As a Parameter Tree, where a nested structure (e.g., Paging) encapsulates pagination details;

Discussion Input

In REST APIs, using multiple query parameters with a GET request can be considered an Atomic Parameter List. To keep this list compact and manageable —especially for error handling— we have decided to limit GET requests to a maximum of five query parameters.

For more complex queries requiring additional parameters, a POST request with a query payload should be used instead.

While the QUERY method has been proposed as a safe, idempotent alternative to GET (allowing request bodies), it is not yet widely adopted. Until it gains broader support, POST with a request body remains the preferred approach for handling complex queries.