One or more techniques and/or systems are provided for facilitating simulation of an application used to access features of a vehicle. For example, an application developer may use an application development environment to develop an application that is used to display information through a vehicle display, obtain telemetry data from the vehicle, and/or modify vehicle features of the vehicle. However, the application development environment may not have real-time access to a vehicle (e.g., while the vehicle is being driven), which significantly reduces the ability to test the application. Accordingly, vehicle parameter signals may be simulated and provided to application code of the application (e.g., the application developer may specify a fan speed as “high”, preprogrammed vehicle speed data may be supplied to the application code, etc.). In this way, the application can be tested as though the application had access to an operational vehicle.