Custom software is software which is specially developed for a few specific organization or other user. As such, it can be contrasted with the use of software packages developed with the mass market, for example commercial off-the-shelf application, or existing free software. Since custom application is developed to get a single customer it might accommodate that patron’s particular preferences in addition to expectations. Custom software could be designed in level by stage operations, allowing all subtleties and possible concealed dangers to be taken into account, including issues that have been not mentioned inside the specifications.