Applied Behavior Analysis (ABA) showed its efficacy in teaching subjects with autism. We discuss the design and development of a free open source customizable software to support ABA intervention in low-functioning children with autism. The software automates the trial setting while enables the gathering of the children' performance data to monitor the learning. The software relies on a Web architecture: using a laptop, the tutor defines the exercises dynamically activated on the child's tablet. Synchronization between these two devices occurs via an Internet connection, obtaining and inserting data through the database. A real-time summary of the actions performed by the child is available on the tutor’s device, simplifying decisions on the intervention. In order to make the trial accessible to any child, the software adapts the visual prompt to the child’s abilities, i.e. receptive/verbal, using labels in addition to images. A pilot test with some children confirmed the usability of the software.