1. A system comprising a processor and a non-transitory computer-readable medium, wherein the non-transitory computer-readable medium embodies one or more program components that configure the computing system to carry out acts comprising: accessing, by an application development environment, code of an application; creating a first base model of the application using the code, the base model representing the underlying code of the application; after creating, receiving input defining a change to the code; in response to the change to the code, creating an edited base model of the application representing the underlying code of the application as changed; creating a new stateful model of the application by processing the edited base model using a transform to simulate the edited base model to a state, the new stateful model representing the appearance of the application when in the state; accessing a previous stateful model of the application, the previous stateful model representing a simulation of the first base model to the state and representing the appearance of the application, prior to the change, when in the state; comparing a node of the new stateful model to a corresponding node of the previous stateful model to identify a change between the new stateful model and the previous stateful model; and providing data identifying the change between the new stateful model and the previous stateful model to a client within the application development environment.