Pseudopedia/Hearts of Iron IV modding

A Hearts of Iron IV mod (modification), or HOI4 mod for short, is an independent, user-made modification to the World War II grand strategy game Hearts of Iron IV. Mods have existed since the earliest Paradox games, and Hearts of Iron IV is integrated with the Steam Workshop for easy sharing, downloading and updating of mods. The game is, by design, very moddable and can be changed with a simple text editor.

Mods range from total overhauls, which typically change the setting of the game and introduce a large amount of new content, to smaller content-based mods, which add or rework content for the playable countries, down to utility mods, which may fix bugs, change graphics or localisation, add cheats, etc. Mods which change anything except for graphics and localisation alter the game's checksum, disabling the player's ability to earn achievements while the mods are enabled and preventing them from playing online multiplayer with people without the same mods enabled.