1. A computer-implemented method, comprising: transmitting, from a contact center builder system to a content provider system of a content provider, instructions that, when executed, provide a graphic user interface for configuring a contact center for the content provider that includes a contact center telephone number, an agent pool, and an interaction site, the interaction site enabling communications between a user device and a communications system over any of multiple communications channels, including an interactive voice response (IVR) channel, wherein the interaction site specifies a multi-step communication flow between the user device and the communications system, and wherein the multi-step communication flow is determined based on multiple interaction pages configurable by a developer of the content provider system; receiving, at the contact center builder system and from the content provider system, data associated with one or more contact center configuration parameters; assigning the contact center telephone number to the contact center based on the data; assigning one or more agents to the agent pool of the contact center based on the data; determining that the data includes a task to be handled by the communications system without using an agent of the agent pool; and in response to determining that the data includes the task to be handled by the communications system without using an agent of the agent pool, generating multiple interaction pages for the interaction site, wherein at least one interaction page of the multiple interaction pages enables a caller of a user device to communicate with the communications system to reach an agent of the agent pool, and wherein at least one other interaction page of the multiple interaction pages enables a caller of a user device to communicate with the communications system to complete the task using the IVR channel without using an agent of the agent pool.