1. A computer-implemented method performed by one or more processors for modifying user interfaces (UIs), the method comprising the following operations: identifying an instance of a UI text element within a UI associated with a software application for modification, wherein the UI is displayed to at least one user; retrieving a first set of metadata associated with the identified instance of the UI text element, where each instance in a plurality of instances of the UI text element is associated with the retrieved first set of metadata based on each instance's instantiation from a single UI text model common to each of the plurality of instances, each of the plurality of instances of the UI text element used in different locations, and wherein at least a portion of the retrieved first set of metadata defines the text presented in the identified instance of the UI text element and each of the others of the plurality of instances of the UI text element, where the retrieved first set of metadata associated with each of the plurality of instances of the UI text element is stored in the single UI text model; receiving at least one modification to the retrieved first set of metadata associated with the identified instance of the UI text element, the at least one modification representing a modification to the defined text presented in the identified instance of the UI text element; and persisting the modified first set of metadata associated with the identified instance by associating the modified first set of metadata with the single UI text model, wherein the text presented in each of the plurality of instances of the UI text element is updated based on the modified first set of metadata associated with the single UI text model common to each of the plurality of instances, wherein persisting includes updating the single UI text model with the modified first set of metadata and invalidating at least one local memory cache storing a runtime version of the first set of metadata associated with the identified instance of the UI text element after persisting the modified first set of metadata associated with the UI text element.