Gartner defines custom software development (CSD) services as the professional services engaged by organizations to design, build, modernize or iterate custom applications and software products to meet their unique business needs. CSD services entail gathering business requirements and coding applications from inception, building applications on a platform as a service (PaaS), or assembling applications from existing web services or other reusable pieces of code. Services marketed as “software product engineering” or “digital product development” likely fall under the CSD services category as defined by Gartner. These solutions are typically not available as commercial off-the-shelf (COTS) products and require custom development.