SDT is the extension of files related to diagramming software called SmartDraw. SDT are files that are used in the program as templates for graphic designs. Contain a pre-formatted project. They allow you to create documents with a specific structure and layout faster. Projects created on the basis of SDT templates may contain flowcharts, charts or other visualizations used, for example, in business.

SmartDraw is a software working under the control of Windows systems and its documents can be exported to files created in MS Office programs.