A microfluidics system for mixing at least two starting materials having a prescribed number of parallel and identical mixing or reaction branches, in which a number of supply ducts corresponding to the number of starting materials open into a mixing or reaction channel. Each of the supply ducts includes an intake line for each starting material, an injection pump for each supply duct and a valve circuit between each intake line for a starting material, where the supply ducts for a respective starting material and a respective injection pump are provided to each respective supply duct. The valve circuit is configured to connect the injection pumps to the suction line in a first valve position, shut off the injection pumps in a second valve position, and to connect the injection pumps to the associated inlet channels in a third valve position. Each of the injection pumps, which are connected to each valve circuit, have a common drive. All mixing or reaction branches connected in parallel can thus be supplied with the same volumetric flow of starting material.