An ARXML file is a configuration file saved in AUTOSAR XML (ARXML) format. It is used by AUTOSAR, an initiative of automotive manufacturers and suppliers formed in 2003 to establish software architecture for automotive electronic control units (ECUs). ARXML files contain configuration and specification information in XML format for an ECU, which is used to control components of an engine to make sure an engine achieves optimal performance.

The ARXML format was developed to standardize data exchange between automotive software development partners. ARXML files are created by the original automobile producer, which means the exact information in each ARXML file may vary. However, the files are typically used to store information about a system description, ECU configuration, or software component description. NOTE: AUTOSAR stands for Automotive Open System Architecture.