In a computer-implemented method of contract execution, data about contracts is stored in a computer storage accessible to a processor of a computer along with data about a procurement plan and data about a purchase request that includes information about a first quantity of at least one good or service. The processor determines a second quantity of the one good or service and a second contract against which to complete the purchase request based on the procurement plan, the data about the contracts, at least one purchase made against one of the contracts, a trigger condition and associated effect, and the quantity of at least one good or service. In response to the second contract and the second quantity being approved, the processor causes a purchase order for the second quantity of the one good or service to be placed to the supplier associated with the second contract.