The formats API provides a mapping from Pokémon Showdown "id" to "Display Name" for cases when the display name cannot programmatically deduced. There is a single valid resource which can be fetched: /formats/index.json.

The correct way to determine the name of current formats is to rely on the information from Pokémon Showdown's config/formats.ts, a version of which is included with the @pkmn/sim package.

The data provided here is only required to support legacy formats - i.e., formats that existed at one point in time and have data present on Unless you are building an historical usage stats viewer you probably do not need this information.

The following transformations are required to properly display the data: