The contribution theorises the lex mercatoria ex machina to indicate the trade usages of the merchants of the emerging crypto economy. Firstly, it situates this new manifestation of the creativity of the mercatores in the long doctrinal history of the idea of lex mercatoria. Secondly, it discusses its main characteristics, namely: the promises of a global technology (i.e., efficiency, rapidity, global and transnational trade), contract automation in managing transitions, the transformation of the idea of trust in commerce and, finally, the preference of mercatores for decentralised justice