A playtest is the process by which a game designer tests a new game for bugs and flaws before bringing it to market. Playtests can be run "open", "closed", "beta", or otherwise.
Playtests are very common with computer games, board games and role-playing games, where they have become an established part of the quality control process.
In the computer games industry, playtesting refers specifically to the process of exposing a game in development (or some specific parts of it) to its intended audience, to identify potential design flaws and gather suggestions. It should not be confused with Quality Assurance (QA) testing, which is the process in which professional testers look for and report specific software bugs to be fixed by the development team.
An open playtest could be considered open to anyone who wishes to join, or it may refer to a game company's recruiting testers from outside. Closed is an internal testing process not available to the public. Beta testing normally refers to the final stages of testing just prior to going to market with a product and is usually run semi-open with a limited form of the game in order to find any last-minute problems.
The playtest concept has even carried over into a full-fledged sport. Jim Foster, inventor and founder of the Arena Football League, tested his concept of indoor football in a special one-time game in 1986. The Rockford Metros and the Chicago Politicians, played the game in Rockford, Illinois. The test proved successful, and four teams began the league's first season the following year.