The MUDDL programming language, "Multi User Dungeon Definition Language", is a domain-specific language for creation of text-based multi-user virtual worlds, i.e. MUDs. The first version of it was written by Richard Bartle and Roy Trubshaw in BCPL; it was later ported to C++ by Viktor Toth. It was originally used to implement MUD1, and was later used for a number of other MUDs, such as MIST.

The MUDDL programming language, "Multi User Dungeon Definition Language", is a domain-specific language for creation of text-based multi-user virtual worlds, i.e. MUDs. The first version of it was written by Richard Bartle and Roy Trubshaw in BCPL; it was later ported to C++ by Viktor Toth. It was originally used to implement MUD1, and was later used for a number of other MUDs, such as MIST.