Custom Software Developer (CSD) is a business

Business

A business is an organization engaged in the trade of goods, services, or both to consumers. Businesses are predominant in capitalist economies, where most of them are privately owned and administered to earn profit to increase the wealth of their owners. Businesses may also be not-for-profit...

 term for companies or individuals specializing in creating made-to-order software for specific customers and applications. The resultant software is not usually a product in the conventional sense of being marketed and sold to a general audience. Rather, it is provided under contract solely to a specific buyer and often cannot be sold or otherwise provided to other buyers.

Custom software is supposed to deliver specialized and/or unique user interface

User interface

The user interface, in the industrial design field of human–machine interaction, is the space where interaction between humans and machines occurs. The goal of interaction between a human and a machine at the user interface is effective operation and control of the machine, and feedback from the...

s, workflow

Workflow

A workflow consists of a sequence of connected steps. It is a depiction of a sequence of operations, declared as work of a person, a group of persons, an organization of staff, or one or more simple or complex mechanisms. Workflow may be seen as any abstraction of real work...

, and system interconnects that provide the buyer with more benefits and resultant value than off-the-shelf applications offer.