Abstract This paper presents an experimental study of a direct-flame type solid oxide fuel cell (DFFC). The operation principle of this system is based on the combination of a combustion flame with a solid oxide fuel cell (SOFC) in a simple, no-chamber setup. The flame front serves as fuel reformer located a few millimeters from the anode surface while at the same time providing the heat required for SOFC operation. Experiments were performed using 13-mm-diameter planar SOFCs with Ni-based anode, samaria-doped ceria electrolyte and cobaltite cathode. At the anode, a 45-mm-diameter flat-flame burner provided radially homogeneous methane/air, propane/air, and butane/air rich premixed flames. The cell performance reaches power densities of up to 120 mW cm−2, varying systematically with flame conditions. It shows a strong dependence on cell temperature. From thermodynamic calculations, both H2 and CO were identified as species that are available as fuel for the SOFC. The results demonstrate the potential of this system for fuel-flexible power generation using a simple setup.