What is a Monorepo?

A monorepo (short for monolithic repository) is a single version control repository that contains multiple distinct projects.

Think of it as one big folder where all your team's related (or even unrelated) codebases live together.

Traditionally, teams use a polyrepo setup, where each project has its own separate repository.

In a monorepo, everything is under one roof. For example, your front-end app, back-end API, and shared UI library could all be in the same Git repository.

A monorepo creates a unified workspace for developers. This means:

• Everyone works from the same repository.
• Dependencies between projects are often local file paths.
• It fosters a sense of shared ownership and consistency.

One major advantage is easy code sharing. If you have common components, utilities, or design systems, they can live once in the monorepo.

All projects can then easily import and use them directly, ensuring consistency and reducing duplication.

Managing dependencies between internal projects becomes simpler. Instead of publishing and consuming packages from registries, projects can directly reference code within the monorepo.

This reduces versioning headaches and makes updates straightforward.

Imagine changing an API and needing to update the UI that consumes it. In a monorepo, you can make both changes in a single commit.

This ensures that all related parts are updated synchronously and tested together, preventing broken builds.

As a monorepo grows, its size can become a concern. The repository history accumulates, making cloning and fetching slower over time.

Tools and strategies are often needed to mitigate this, such as sparse checkouts or shallow clones.

Without careful planning, building and testing a large monorepo can be slow. A change in one small file might trigger a full rebuild of everything.

This requires sophisticated build systems and tools that understand project dependencies to optimize build times.

While Git itself supports monorepos, managing them efficiently often requires specialized monorepo tools.

These tools help with tasks like running commands across specific projects, managing dependencies, and optimizing builds. We'll explore these later!

Let's check your understanding of monorepos.

Great job! You've learned the core concept of a monorepo.

• It's a single repository for multiple projects.
• Benefits include easier code sharing, simplified internal dependencies, and atomic changes.
• Drawbacks involve potential for large size, complex builds, and the need for specialized tooling.

Next, we'll dive into how to structure these unified workspaces!