Custom software is software that is specially developed

Software development

Software development is the development of a software product...

 for some specific organization or other user. As such, it can be contrasted with the use of software packages developed for the mass market

Mass marketing

Mass marketing is a market coverage strategy in which a firm decides to ignore market segment differences and go after the whole market with one offer. It is type of marketing of a product to a wide audience. The idea is to broadcast a message that will reach the largest number of people possible...

, such as commercial off-the-shelf

Commercial off-the-shelf

In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...

 (COTS) software, or existing free software

Free software

Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...

.

Custom software can be developed by an in-house software development group, or be commissioned from a software house

Software house

A software house is a company whose primary products are software.- Types :There are a number of different types of software houses:*Large and well-known companies such as Microsoft, SAP AG, Oracle Corporation, HP, Adobe Systems, Apple Inc...

 or independent software developer

Software developer

A software developer is a person concerned with facets of the software development process. Their work includes researching, designing, developing, and testing software. A software developer may take part in design, computer programming, or software project management...

.

Since custom software is developed for a single customer it can accommodate that customer's particular preferences and expectations. Custom software may be designed in stage by stage processes, allowing all nuances and possible hidden dangers to be taken into account, including issues which were not mentioned in the specifications. Especially the first phase in the software development process

Software development process

A software development process, also known as a software development life cycle , is a structure imposed on the development of a software product. Similar terms include software life cycle and software process. It is often considered a subset of systems development life cycle...

 may involve many departments, including marketing

Marketing

Marketing is the process used to determine what products or services may be of interest to customers, and the strategy to use in sales, communications and business development. It generates the strategy that underlies sales techniques, business communication, and business developments...

, engineering

Engineering

Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...

, research and development

Research and development

The phrase research and development , according to the Organization for Economic Co-operation and Development, refers to "creative work undertaken on a systematic basis in order to increase the stock of knowledge, including knowledge of man, culture and society, and the use of this stock of...

 and general management

Management

Management in all business and organizational activities is the act of getting people together to accomplish desired goals and objectives using available resources efficiently and effectively...

.

Large companies commonly use custom software for critical functions, including content management

Content management

Content management, or CM, is the set of processes and technologies that support the collection, managing, and publishing of information in any form or medium. In recent times this information is typically referred to as content or, to be precise, digital content...

, inventory management, customer management, human resource management

Human resource management

Human Resource Management is the management of an organization's employees. While human resource management is sometimes referred to as a "soft" management skill, effective practice within an organization requires a strategic focus to ensure that people resources can facilitate the achievement of...

, or otherwise to fill needs that existing software packages cannot. Often such software is legacy software, developed before COTS software packages offering the required functionality became available.

Custom software development is often considered expensive compared to off-the-shelf solutions or products. This can be true if one is speaking of typical challenges and typical solutions. However, this is not always true. Custom software development by a renowned vendor is often a matter of building a house upon a solid foundation. This can be done quickly and with top-notch quality designed to meet every client's needs.