Abstract: A method of dynamically performing data transformations on information that is transmitted between a user device and a web service may include receiving interface code from the web service, receiving an input from the user device that identifies a data type, and a data transformation to be applied to data instances matching the data type. The method may also include causing a definition file to be stored with the data type, the data transformation, and a resource locator. The method may additionally include, in a second communication session, intercepting a transmission, accessing the definition file using the resource locator, determining whether the data instance matches the data type, causing the data transformation to be performed on the data instance to generate transformed data, and inserting the transformed data into the transmission if the data instance matches the data type.