Alpha software is computer software that is still in the early testing phase. It is functional enough to be used, but is unpolished and often lacks many of the features that will be included in the final version of the program. The "alpha phase" of software development follows the early programming and design stages, but precedes the "beta phase" in which the software closely resembles the final version.
Since the alpha phase is an early part of the software development cycle, alpha software typically includes significant bugs and usability issues. Therefore, while beta software may be provided to the public, alpha software is only tested internally. The alpha stage is also important for competitive reasons, as the developer may not want to disclose the new features of a software program until shortly before the release date.
If a developer is building a small application, he may be the only person who ever tests the alpha version. Larger programs, however, are often tested internally by a team of developers during the alpha phase. In some cases, multiple teams may work together on the alpha version of a software program. Once the programmers have built a working version with all the necessary features, the lead developer may decide to implement a "feature freeze," which means no additional features are planned for the current version of the program. This often signals the end of the alpha phase and the beginning of the beta stage of development.