The process of designing, building, deploying, and supporting software specifically for a group of users, tasks, or organizations is known as custom software development. Custom software development, as opposed to commercial off-the-shelf (COTS) software, focuses on meeting a specific set of needs. Because COTS addresses a wide range of criteria, it can be packaged, professionally advertised, and delivered. 

On the other hand, custom software is created to meet a specific set of requirements, such as:

• a manufacturer’s field service equipment maintenance program or an online
• banking application created specifically to meet the needs of the bank and its clients.

Either in-house development teams or outside contractors typically create custom software. The same approaches and procedures used for other types of software development also apply to the creation of custom software. The same processes, such as Agile, DevOps, or Rapid Application Development, would be used for a custom project as they would for any other software project: gathering requirements, writing code, testing, and deploying. 

Application administration, application modernization, and application customization are tasks related to the creation of custom software. Application customization is the process of altering commercial off-the-shelf (COTS) software to accommodate unique needs. Application modernization is essential for ensuring that a company’s proprietary software will continue to be functional and satisfy changing customer and market expectations. By enabling operations including installation, upgrading, performance and availability optimization, and service desk duties, application management increases the effectiveness of the software.