MAPP – A web-based decision support system for the mould industry. This paper describes the MAPP, “Mould: Assistant Production Planner”, a web-based decision support system developed for the mould industry. MAPP addresses two subsystems considered fundamental by the managers of a case study company: (1) production planning and control and (2) information and document management. The production planning methodology implemented is based on the workload control concept developed at Lancaster University, adapted to the context of the moulds industry, under a Rapid Prototyping case study. The main objectives of this paper are to present a discussion of the system functions at the service of the planning methodology, and to explain the development decisions in the socio-technical context of the case study company. We conclude with a brief overview of issues raised in lab and field testing, along with some proposals for further research.