Methods, systems, and computer program products for generating a data stream for broadcast to one or more client systems. A source identifier identifies where the data for the data stream may be obtained. Scheduling information associated with the identifier determines when the data should be added to the data stream for broadcast. The data is requested and received from the data source using the identifier and added to the data stream to arrive at the one or more client systems in accordance with the scheduling information. The generated data stream may comprise one or more sub-streams. The scheduling information may be checked or validated to assure consistency and accuracy. Client systems may simultaneously receive data, including real-time data, from multiple sources.