Monorepo vs Polyrepo: Which Codebase Strategy Fits You Best?
Engineering teams often debate whether they should maintain a monorepo or a polyrepo structure. Both approaches have their strengths and weaknesses depending on team size, tooling, deployment strategy, and the number of services being managed.
What is a Monorepo?
A monorepo stores all projects, applications, and shared libraries in a single version-controlled repository. Companies like Google, Meta, and Uber famously use monorepos at scale.
Advantages
- Single source of truth: All services and libraries stay consistent.
- Easier code sharing: Shared utilities and modules live in one place.
- Simplified refactoring: Cross-project changes happen atomically.
- Standardized tooling: One CI pipeline, one linting setup, one dependency management system.
Disadvantages
- Scaling issues: Large monorepos become slow without advanced tooling (Bazel, Lerna, Nx).
- Permission complexity: Harder to isolate access for specific teams.
- Heavy CI: Naive pipelines may run more tests than needed.
What is a Polyrepo?
A polyrepo architecture keeps each service, app, or library in its own dedicated repository. This is the traditional approach used by many small and mid-sized teams.
Advantages
- Clear ownership: Each repo maps cleanly to a single team or service.
- Lightweight repositories: Faster cloning and reduced tool complexity.
- Independent versioning: Each project can release on its own schedule.
Disadvantages
- Harder to maintain consistency: Different repos can drift with tooling, dependencies, or lint rules.
- Duplicated code: Shared utilities often get copied instead of centralized.
- Cross-project changes are painful: Updating multiple repos requires careful coordination.
When to choose which?
Choose a Monorepo if:
- You have many interconnected services or shared libraries.
- Your team values unified tooling and cross-project visibility.
- You can invest in build tooling (Nx, Bazel, Turborepo).
Choose a Polyrepo if:
- You want simple, independent deployment pipelines.
- Your organization has clear ownership boundaries.
- You prefer small, focused repositories with minimal tooling.
Final thoughts
There is no universal “best” approach — only the best approach for your team. Small teams often start with polyrepos for simplicity, while growing companies switch to monorepos for consistency and centralized control. The key is choosing the model that aligns with your workflow, deployment strategy, and long-term scaling plans.
