The Genealogie Online Data API allows third-parties to access genealogical data from Genealogie Online publications.
The Genealogie Online Data API provides several methods which are described in Open API Specification (Swagger 2.0) format which can be downloaded (YAML) or viewed (and interacted with) online (Swagger-UI).
The Genealogie Online Data API can only be used by known third-parties, which have to get permission from the Genealogie Online user. Authentication is handled using OAuth2, which is described in detail on the Oauth2 page.