The simultaneous feasibility test (SFT) performs the network sensitivity analysis under the base case and contingency cases in power systems. This paper presents the practical implementation of the simultaneous feasibility test in the energy market. SFT calculation includes loss sensitivities and constraint shift factors either for E-nodes or P-nodes and the used reference is the distributed load reference. Several SFT modes are discussed in the paper. The schematic of data flow between SFT and other market system applications in a day-ahead market clearing process is also analyzed. Especially, the dead bus logic is proposed to compute the sensitivities for the open/dead node such as open unit. The calculating results based on PJM system are shown in the paper.