Memo Bank, established in 2017 to cater to Small and Medium Businesses (SMBs), has carved a niche by offering a tech-driven banking experience tailored to the unique requirements of these enterprises. Under the leadership of Jérémie Martinez, the engineering team has developed a sophisticated Core Banking System (CBS) and a robust API ecosystem that includes both public and partner APIs, adhering to regulations like PSD2. Their code-first approach, leveraging OpenAPI 3.0 and tools such as JaxRS and RestEasy, ensures automated and elegant documentation, crucial for their clients who need seamless banking operations. The bank's use of event-driven APIs with technologies like Kafka and ActiveMQ enhances traceability and auditing capabilities. With support from Bump.sh, Memo Bank has streamlined its API documentation process, integrating it with GitLab to facilitate efficient change management. The bank's journey from acquiring a banking license from the Banque de France in 2020 to launching their service showcases their commitment to redefining banking for SMBs, standing apart from traditional banks and FinTechs focused on larger businesses or individuals.