An API, in simple terms, is a method by which two software components can communicate with each other, and provides the software developer with a set of routines and tools they can use to build new software on.
Prior to PCRecruiter 8.5, the API was only available for use by Main Sequence’s own development team, most prominently as the basis for allowing the PCRecruiter Portal for Microsoft Outlook product to ‘talk’ to the PCRecruiter servers. With the public release, Main Sequence clients may now contract independent developers to write custom software that links to the PCRecruiter database, such as job boards, import/export tools, mobile applications, data integrations, and so on.
It should be noted that the API is a tool with which a qualified programmer may build new, custom software integrated with the PCRecruiter database, but cannot be used for altering the PCRecruiter software itself, which remains solely under the control of Main Sequence.
The documentation for the REST API can be found at https://www.pcrecruiter.net/apidocs_v2/