Identifier acquisition methods and apparatuses, devices and media are provided. When an identity token carried in an identity authentication request from a master application client is authenticated, an application management terminal transmits a first user identifier registered in the master application client by a target user corresponding to user information carried in the identity authentication request to the master application client. The master application client transmits the first user identifier and the identity token to a micro application client, so that the micro application client transmits an identifier acquisition request carrying the first user identifier and the identity token to the application management terminal. When the identity token in the identifier acquisition request is authenticated, the application management terminal acquires a second user identifier corresponding to the first user identifier in the micro application client, and transmits the second user identifier to the micro application client.