Monorepo vs polyrepo

How you split your code into repositories seems like a plumbing decision, but it quietly shapes how your team collaborates, ships, and reasons about the system. A monorepo keeps everything in one repository; a polyrepo gives each service or app its own. Neither is universally right, and the loudest opinions online usually ignore your actual stage and team size. Here's how to think about it clearly. What a monorepo buys you A monorepo puts your web app, mobile app, backend, and shared libraries under one roof. The advantages are real, especially for smaller teams: Atomic changes. Update a shared type and every consumer in the same pull request. No cross-repo coordination dance. One source of truth for tooling. A single lint, format, and CI config instead of drift across a dozen repos. Effortless code sharing. Shared TypeScript packages are just imports, not published versions you have to bump and reinstall everywhere. Easy refactoring. You can find and fix every caller of a function because it's all in front of you. Tools like Turborepo and Nx make this practical by caching builds and only running work for the parts that actually changed. What a monorepo costs The trade-offs show up as you grow. Build and CI times can balloon without smart caching. Access control is coarser — it's harder to give a contractor one service without the whole codebase. And a naive setup rebuilds and tests everything on every change, which gets slow fast. Good tooling mitigates all of this, but you have to invest in it deliberately. What a polyrepo buys you Separate repositories give each service hard boundaries . A team owns its repo end to end, deploys on its own schedule, and can't accidentally reach into another team's internals. Access control is naturally granular, CI for each repo is small and fast, and the blast radius of a bad change is contained. The cost is coordination. A change that spans services becomes multiple pull requests across multiple repos that must land in the right