Abstract: The invention relates to a process and an apparatus for catalytically reforming hydrocarbons or alcohols to hydrogen in a plurality of partial reactions. The plurality of partial reactions are performed individually and/or in combinations of at least two of the plural partial reactions in a microreactor network comprising microreactors and channels formed between the microreactors, starting substances and/or reaction products of the plural partial reactions being conveyed through at least part of the channels between reactor spaces of the microreactors. Reaction progress of the plural partial reactions in the microreactor network is controlled by way of process control means for controlling process parameters.