Certain aspects of the disclosure are directed to customization of alerts using telecommunications services. A data-communications server is configured to provide a database with a set of virtual office features including client-specific call routing functions available to remotely-situated client entities based on a subscription. The server is configured to provide to the client entities, a set of instructions written in a first programming language, and to receive from each respective client entity, client-specific sets of control data written in a second programming language. The client-specific sets of control data may specify particular alerts and/or reminders to be provided to end-users of the respective client entity.