ORCID provides two core functions: (1) a registry to obtain a unique identifier and manage a record of activities, and (2) APIs that support system-to-system communication and authentication. ORCID makes its code available under an open source license, and will post an annual public data file under a CC0 waiver for free download.   The ORCID Registry is available free of charge to individuals, who may obtain an ORCID identifier, manage their record of activities, and search for others in the Registry. Organizations may become members to link their records to ORCID identifiers, to update ORCID records, to receive updates from ORCID, and to register their employees and students for ORCID identifiers.