List of Microsoft codenames

Microsoft codenames are given by Microsoft to products it has in development before these products are given the names by which they appear on store shelves. Many of these products (new versions of Windows in particular) are of major significance to the IT community, and so the terms are often widely used in discussions before the official release. Microsoft usually does not announce a final name until shortly before the product is publicly available. It is not uncommon for Microsoft to reuse codenames a few years after a previous usage has been abandoned.

There has been some suggestion that Microsoft may move towards defining the real name of their upcoming products earlier in the product development lifecycle to avoid needing product codenames.

Windows platform engineering milestones
The following are code names used for internal development cycle iterations of the Windows core, although they are not necessarily the code names of any of the resulting releases. With some exceptions, the semester designations usually matches the Windows version number.