The deliverable D3.1 presents the design, development, and preliminary evaluation of the NERO cybersecurity marketplace, addressing SMEs' unique cybersecurity needs. It starts with a state-of-the-art analysis of existing marketplaces, identifying challenges, best practices, and gaps. The document outlines a user-centric approach, incorporating extensive requirements gathering, collaborative design, and iterative development. Key functionalities developed in the first phase include security assessment tools, advisory services, and incident response support. A structured evaluation methodology assesses market readiness, technical feasibility, usability, and impact on cybersecurity resilience. Findings highlight the platform's potential in strengthening SMEs' security posture while identifying areas for improvement. The document discusses technical implementation, integration with existing tools, and scalability considerations. User feedback and pilot testing results provide insights into the platform’s effectiveness and adoption barriers. Identified limitations and challenges will guide the enhancements planned for the next development phase. A second version of the marketplace will address identified gaps and incorporate further refinements. The evolution of the platform will focus on improving automation, intelligence-driven security recommendations, and broader service offerings. Future iterations aim to enhance interoperability with other cybersecurity frameworks and tools. Insights gained from this phase contribute to the strategic roadmap for NERO's long-term impact. These advancements will be reported in D3.2, ensuring continuous improvements aligned with SMEs' evolving needs.