Described are computer-based methods and apparatuses, including computer program products, for allowing a user to switch between interfacing with a service through a network or through short message service (SMS). A chat service is executed through which a first user at a first computer can communicate directly with a second user at a second computer. A request is received from the first computer to enable the first user to interface with the chat service through a mobile device of the first user using SMS instead of through the network using the first computer. The chat service is configured to interface with the mobile device through SMS, including communicating chat information through SMS to the first user's mobile device, and communicating control information through SMS to the first user's mobile device such that the first user can control a full functionality of the chat service using SMS.