1. A computer-implemented method for managing access to metadata related to application programming interfaces (APIs), the method comprising: receiving, by a server, a request for metadata related to one or more APIs from an API client; searching, by the server, an API directory based on the request, the API directory having a plurality of APIs each of which have a respective directory entry and a respective discovery document, to find a directory entry corresponding with the request, the directory entry having a link to a location of a discovery document; parsing the directory entry to obtain the link to the location of the discovery document; and retrieving, by the server, the discovery document from the API directory based on the link in the directory entry, that contains machine-readable metadata related to one or more functions of the one or more APIs.