OTX Builder is an integrated solution for specifying, implementing, and executing OTX (ISO 13209) based diagnostic test sequences by simple drag and drop operation and HMI editor to design UI in very simple WYSIWYG screen layout. Integrated OTX executor performs step by step debugging, monitoring and execution of authored HMI screens and OTX sequences (for proximity, remote and in-vehicle use cases). Data integrity, consistency is ensured by continuous validation based on standard & custom OTX checker rules. It also facilitates integrated report generation for OTX sequence APIs, along with auto generation of requirement specifications from OTX test sequences & HMI.