Aspects of subject technology provide systems and methods for generation and distribution of a stable identifier associated with multiple aliases of a user account. The stable identifier may be provided to various electronic devices by a server, responsive to requests associated with communications to those devices from one of the associated aliases. In this way, messaging applications can utilize the stable identifier to merge conversations from a single user having multiple aliases, and secure access to a secure device can be provided to an authorized user, even if the authorized user attempts access from an unauthorized account alias.