This article is incomplete and waiting on someone to expand it.

Mod for mod

Mod for mod (also known as M4M) is a term that describes a trade between two or more creators. It requires each creator to mod the other's beatmap.

This term is usually found on the forums where users review each other's maps, but may also be found on user profiles and external sites.

Mod for mods have historically been favoured over regular mods since both parties benefit from this deal, though have become less common in recent years.