<b>Abstract</b>— <p>The architecture and capabilities of a computer system being developed for analyzing the weldability of steels, the demonstration version of which is available at weldability.ru, are presented. This system consists of modules for inputting and verifying user-provided initial data, analyzing the main physical and metallurgical processes, optimizing technological parameters according to specified criteria, as well as modules for interaction with external software and output of final results. The system enables calculations of key weldability indicators for typical and geometrically unique welded structures and joints, significantly simplifying the design and technological preparation of welding of critical components.</p>