Abstract With growing demands for sustainability and circularity in the construction sector, enhancing the reusability of steel components has become a key priority. The European CONNECT4C project addresses this challenge by developing innovative, adaptable steel components that enable flexible and reusable structural systems. This paper investigates newly developed moment‐resisting double‐sided beam‐to‐beam steel joints, focusing on the preparation of the experimental campaign and a preliminary numerical study. The aim is to assess the joint's moment resistance, rotational stiffness, ductility, deformation capacity, and failure mechanisms.