TOPFARM is an optimization platform, which takes the investors perspective and performs an economical optimization of the wind farm layout throughout the lifetime of the wind farm. The economical optimization approach differs significantly from the traditional power output optimization. The major differences are highlighted, and the TOPFARM platform is described in some detail. The capability of the platform is illustrated in two demonstration examples. In the first example we perform a sanity check of basic features of the TOPFARM objective function. The second example demonstrates the capability of economical layout optimization, when applied on the Danish Middelgrunden offshore wind farm.