A microfluidic device comprising a plurality of microreactors is provided. Each microreactor includes at least a first inlet and a second inlet for supplying a first fluid and a second fluid, respectively, to said microreactor and at least one waste channel for draining fluid from said microreactor. The device further comprises a shared first microfluidic supply system for supplying a first fluid to the first inlets of the plurality of microreactors, a shared second microfluidic supply system for supplying a second fluid to the second inlets of the plurality of microreactors. At least one of said inlets to each microreactor comprises at least one valve-less fluidic resistance element having a fluidic resistance that is substantially larger than the fluidic resistance of the corresponding shared microfluidic supply system. A chemical reaction sequencer apparatus including the microfluidic device and a method for supplying reagents to a plurality of microreactors are also provided.