Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterised by difficulties in communication and repetitive behaviors. The early detection of ASD is a clinical priority in education centres and medical services. COREAT is a computer adaptation of the Repetitive Behavior Scale-Revised (RBS-R) which has been designed to facilitate the diagnosis of individuals with ASD and intellectual disability. This article describes the development, an initial evaluation of the feasibility and the preliminary outcomes of COREAT. The development of COREAT consists of two phases. Phase 1: Performing a prior analysis of the psychometric properties of the RBS-R scale. Phase 2: Developing the mobile application (pilot tests, testing real cases n = 11, and final feedback). Descriptive data of the pilot study shows that 91.31% of participants indicate that COREAT is very accessible and intuitive. COREAT proves to be a useful diagnostic resource for professionals and families. Cross-cultural differences must be analysed.