Alpha software is software that is still in the phase of early detection. It's functional enough to be used, but it is dull and often lack many features that will be included in the final version of the program. The "alpha phase" of software development follows the steps of programming and design at first, but before the "beta" in which the software is much like the final version.
Since the alpha phase is the beginning of a cycle of software development, an alpha version usually includes significant bugs and usability issues. Therefore, any beta software can be provided to the public, an alpha version is only tested internally. The alpha stage is also important for competitive reasons, the developer may not want to disclose the new features of this software until shortly before the release date.
If a developer is to build a small application, it may be the only person who has ever tested the alpha version. Larger programs, however, are often tested in-house by a team of developers in the alpha phase. In some cases, several teams can work together on the alpha version of the software. Once the programmers have built a working version with all the features required, the lead developer may decide to set up a "feature freeze", which means no additional features are planned for the current version of the program. This often indicates the end of the alpha phase and the beginning of the beta phase of development.