Embodiments of this application relate to the field of communications technologies, and disclose an application programming interface (API) topology hiding method, a device, and a system, to hide, from an API invoker, an API exposing function (AEF) that provides an API. The method includes: receiving, by a common API framework core function (CCF) from a topology hiding request entity, a request message that includes information about an API and that is used to request to hide an AEF that provides the API; determining, based on the request message, a topology hiding entry point used by an API invoker to invoke the API; and sending, to the topology hiding entry point, an identifier of the API and an identifier of the AEF that provides the API, so that the topology hiding entry point hides the AEF that provides the API.