The expansion of renewable energies along with a simultaneous increase in electrification of consumers in the lower voltage levels is increasingly leading to congestions in the electricity grid and to a rising complexity in the operational planning of grid operators. The Altdorfer Flexmarkt - a smart market platform - is a concept for the utilization of flexibility, their efficient use and the assurance of a coordinated call-off. The paper starts with a meta-study of comparable smart market concepts and their basic principles. Combined with today's operational planning processes for grid operators the smart market concept used for the Altdorfer Flexmarkt is derived. Its functionality is afterwards described by an explanation of the basic structure and key modules.