An assessment of consistency in URI format and response data across eight RESTful APIs providing data for taxa, using criteria commonly used in API design and the Darwin Core standard for data sharing. A: URIs should indicate that they are part of an API either via a subdomain or a URL segment. B: APIs should be versioned as functionality evolves and the version indicated in the URI. C: API endpoints can be nouns or verbs, but nouns are typically recommended. D: If an endpoint is a noun, is it a Darwin Core class (in this case Taxon)? E: APIs typically provide access to individual data records via a URI that includes the record identifier as a URL segment, and not using a query string. F: GET requests for a single data resource should return a single object, and not an array. Conversely, queries should return an array, as in H. G: Some APIs require the response format be included in the URI. This is better achieved using request headers. H: When querying a collection, the response object includes a property for the array of search results. The name of that property is not standardized. I: Darwin Core provides a standard for data sharing between systems that have differing internal data schemas, facilitating use and understanding of data by third parties as well as easier integration and use of APIs. Darwin Core terms are not widely applied in APIs however. J: Related to I, we assessed the terms used for full taxon name in API response data, or the equivalent dwc:scientificName. K: The formal definition of dwc:scientificName is that it must include the taxon authority. It seldom does. L: Darwin Core also provides an atomic term for the taxon authority, dwc:scientificNameAuthorship. A range of different terms are currently used to represent this concept in API response data.

  Part of: Engelbrecht I, Steyn HM (2021) Does TDWG Need an API Design Guideline? Biodiversity Information Science and Standards 5: e75372.