What is monorepo? (and should you use it?)

A monorepo, a version-controlled repository containing multiple projects, offers several advantages such as enhanced visibility, simplified dependency management, and improved collaboration across teams, but it also presents challenges like scalability issues and steep learning curves. Companies like Google, Microsoft, and Facebook have adopted monorepos to foster rapid development workflows, benefiting from a unified code base that simplifies enforcing quality standards and managing dependencies. However, as monorepos grow, they may suffer from performance issues, broken masters affecting all users, and increased complexity, which can lead some companies to switch to multirepos or adopt hybrid approaches. Experiences from companies like Segment, Airbnb, Uber, and Pinterest highlight the importance of investing in tooling, such as advanced build systems and version control enhancements, to mitigate these challenges. Ultimately, the decision between monorepo and multirepo strategies is not purely technical but also depends on organizational communication and culture, with the choice reflecting the desired workflow and collaboration style.