Architectural trends in software development have evolved with technological advances such as virtualization, containers, and cloud computing, leading to the adoption of microservices and Service-Oriented Architecture (SOA). Despite predictions that these innovations would replace traditional monorepos, both approaches coexist, offering distinct advantages in managing codebases, especially in Continuous Integration (CI). Monorepos centralize code management, streamline CI processes, and allow for cross-project visibility, while multi-repos provide isolated management and CI flexibility for individual projects. Leading tech companies like Google, Facebook, and Uber have demonstrated the scalability and benefits of monorepos, though they require significant investments in tooling and infrastructure. The choice between monorepos and multi-repos depends on organizational needs, project interdependencies, and team structures, with some opting for a hybrid approach. Buildkite emerges as a suitable CI tool for monorepos, offering dynamic pipelines, parallelization, and customizable build environments, ultimately bridging technological advancements with strategic monorepo advantages.