LPMud, abbreviated LP, is a family of multi-user dungeon (MUD) server software. Its first instance, the original LPMud game driver, was developed in 1989 by Lars Pensjö (the LP in LPMud). LPMud was innovative in its separation of the MUD infrastructure into a virtual machine (termed the driver) and a development framework written in the programming language LPC (termed the mudlib).