Techniques are described for providing clients with access to functionality for creating, configuring and executing defined workflows that manipulate source data in defined manners, such as under the control of a configurable workflow service that is available to multiple remote clients over one or more public networks. A defined workflow for a client may, for example, include multiple interconnected workflow components that are specified by the client and that each are configured to perform one or more types of data manipulation operations on a specified type of input data. The configurable workflow service may further execute the defined workflow at one or more times and in one or more manners, such as in some situations by provisioning multiple computing nodes provided by the configurable workflow service to each implement at least one of the workflow components for the defined workflow.