Pokémon Showdown

Pokémon Showdown, also often formatted as Pokémon Showdown!, is a popular Pokémon battle simulator, currently peaking close to 10,600 users. As of July 2, 2012, it was adopted by Smogon and became one of the first battle simulators to support the changes brought about by Black 2 and White 2. In addition to standard modes of play, Pokémon Showdown! includes unique features such as the emerging tiers “Hackmons” and “Balanced Hackmons,” which encompass Pokémon of normally illegal movesets and abilities and are not supported by any other popular simulator.

Pokémon Showdown is web-based and works on all major browsers. It is written in JavaScript and Node.js, and it is free and open source.