In software development and product management, a user story is a description consisting of one or more sentences in the everyday or business language of the end user or user of a system that captures what a user does or needs to do as part of his or her job function. User stories are used with agile software development methodologies as the basis for defining the functions a business system must provide, and to facilitate requirements management. It captures the "who", "what" and "why" of a requirement in a simple, concise way, often limited in detail by what can be hand-written on a small paper notecard.
A user story encapsulates the action of one function making it possible for software developers to create a vertical slice of their work.
User stories originated with Extreme Programming (XP), whose first written description in 1998 only claimed that customers defined project scope "with user stories, which are like use cases". Rather than offered as a distinct practice, they were described as one of the "game pieces" used in the planning game. However, most of the further literature thrust around all the ways arguing that user stories are "unlike" use cases, in trying to answer in a more practical manner "how requirements are handled" in XP and more generally Agile projects. This drives the emergence, over the years, of a more sophisticated account of user stories.