Building sustainable, community-led infrastructure for scholarly communication is a key priority in the Netherlands. Within the framework of the Open Science NL funding programme, three complementary projects have been awarded to jointly develop a shared national infrastructure for scholarly publishing. In addition, a fourth project has been funded to establish a formal alliance of University Presses in the Netherlands (NUPs). Together, these initiatives aim to strengthen non-profit, Diamond Open Access publishing and to improve coordination, interoperability and efficiency across the Dutch scholarly publishing landscape. The project Scaling Small focuses on supporting the Netherlands University Presses by developing a national catalogue and a shared metadata management system for book publishing. This provides a scalable technical foundation that enables presses to professionalise workflows while retaining their local identity and autonomy. Enabling and Strengthening Open Institutional Publishing complements this technical work by reinforcing the NUPs network as a sustainable, inclusive and collaborative ecosystem for Diamond Open Access publishing. It does so by expanding partnerships, fostering knowledge exchange and increasing efficiency through shared editorial services, metadata practices and innovation support. At the same time, the Openjournals publication platform is expanding its activities with book publishing by building an installation of Open Monographs Press. Finally, the four-year project Infrastructures for Diamond Open Access in the Netherlands brings together universities, the Royal Netherlands Academy of Arts and Sciences (KNAW), and SURF. This collaboration aims to integrate a range of existing publication platforms into a high-quality, flexible national infrastructure. The resulting infrastructure will be made available to university presses, research institutes, and other research organisations that wish to publish their own articles, journals, and (text)books. It will be embedded within the broader Dutch Open Research Information ecosystem. This poster showcases how these projects are technically and strategically connected, how they collectively contribute to a shared national infrastructure, and how their activities align with current national policy developments, including the Dutch National Open Access Strategy and the Strategic Plan for an Integrated Infrastructure for Open Science.