CDISC USDM (DDF) Study Definitions API
CDISC-published OpenAPI for the USDM (Unified Study Definitions Model) study-definitions interface from the Digital Data Flow programme — create, update, read and version a study definition and search study designs. The repository describes it as a DDF emulation: a reference contract and implementation for the community rather than a CDISC-operated production service, so no baseURL is recorded.