Microsoft Visio SDK

Microsoft Visio SDK screenshots

It contains tools that you need to develop custom solutions for Visio
Main window
Microsoft Visio SDK 14.0 : Main window

Alternative downloads

Microsoft Office Visio
Create flowcharts, network diagrams, floor plans, and other designs.
16.0.11601.20204
Microsoft Windows SDK for Windows
It's a tool that provides documentation that help you Windows applications.
10.1.17134.12
FREE
Office SharePoint Server 2007 SDK
Designed for solution providers or independent software vendors.
12.0.4518.1144
FREE