Cordra provides three different programmable interfaces in addition to a graphical interface for web browsers.

HTTP REST API, Digital Object Interface Protocol (DOIP), and Identifier/Resolution Protocol (IRP) are the three programmable interfaces. The software distribution includes client libraries for Java, JavaScript, and TypeScript developers.


Cordra provides a RESTful HTTP API for interacting with digital objects. The HTTP REST API reduces the entry barrier and enables users to leverage Cordra’s features using most HTTP client libraries, although the Cordra distribution itself includes client libraries, both a Java version and a JavaScript/TypeScript version.

Digital Object Interface Protocol (DOIP) Interface

DOIP is a communication protocol that specifies how clients may interact with digital objects (DOs) that are managed by DOIP services. The method of such interaction is primarily using identifiers associated with digital objects, including those that represent operations, types, and clients.

DOIP is an appropriate choice for users who are interested in an architectural style focused on invoking identified operations, or who focus on persistence or interoperability benefits.

For details about the Cordra’s implementation of DOIP along with examples, see DOIP and Examples. For information about DOIP client library, see DOIP Client Library - Java Version. See also DOIP API for HTTP Clients.

Identifier/Resolution Protocol (IRP) Interface

IRP is a rapid resolution protocol for retrieving state information, such as location, public keys, and digests, of a digital object from its identifier.

IRP is originally defined under a different name in RFCs 3650, 3651, and 3652. IRP specification, and its evolution, is currently overseen by the DONA Foundation as part of the Handle System.

Cordra provides an IRP interface enabling clients to rapidly resolve digital object identifiers to their state information. You may access IRP client libraries here.

See Identifiers and Handle Integration for more information about configuring Cordra identifiers and its IRP interface.