The landscape of persistent identifiers, PIDs has expanded considerably in the last years and the information you need to start integrating persistent identifiers depends on your use cases. Some services will be concerned with creating DOIs while others simply need to query the metadata. Likewise, some systems may require authenticated ORCID IDs to aid interoperability, others will want to retrieve metadata or update records. New PID infrastructures open up opportunities for new functionalities and graphing new connections. We have collected here some features for developers that aim to integrate or build on current and new PID infrastructures and their extended services.
Identifiers for research organizations have been consolidated under ROR, which provide organization identifiers that are globally unique, stable, discoverable, and resolvable. In addition, ROR provides an appropriate metadata schema for organizations and resolves interoperability with other identifiers through relationship metadata.
Datacite has expanded its services to include provenance data in form of Prov API (Application Programming Interface). The DataCite GraphQL API provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools. Blog by Martin Fenner on the API.
The Crossref REST API is one of a variety of tools and APIs that allow anybody to search and reuse our members’ metadata in sophisticated ways. Documentation for Crossref’s API is available through [Github](https://github.com/CrossRef/rest-api-doc](https://github.com/CrossRef/rest-api-doc)