Monorepos

Introduction

🔧 Problems with Polyrepos:

Dependency mismatches (e.g., API version conflicts).
Complicated CI/CD workflows (multiple pipelines).
Difficult code sharing (shared code across services).

💡 Solution: Monorepos

Single Git repository for multiple projects.
Centralized dependency management and code sharing.
Efficient CI/CD with optimized builds.

Full-stack applications often consist of multiple interconnected projects, such as the front end, back end, and shared libraries. Managing them separately in multiple repositories can lead to ...

... version mismatches, where front-end and back-end use different versions of a shared API library

... complex deployments, where each repository needs separate CI/CD pipelines

... and code duplication, where code reuse across services is cumbersome

A monorepo (short for monolithic repository) is a single Git repository that ...

... stores multiple projects within it.

Instead of managing multiple repositories for different parts of a full-stack application, everything is stored in one place, making development, collaboration, and maintenance easier.

Moreover, your CI/CD pipelines can be optimised running only when dependent packages have changed.

Monorepos

Example

A React-based front end (customer UI).
A Python API (backend services).
A shared authentication library used by both.
A documentation site
A shared UI library
E2E (System) Tests

Monorepos

Tools

Tool	Language	Use Case
Nx	JavaScript/TypeScript	Optimized for large-scale apps, caching, and task execution
Turborepo	JavaScript/TypeScript	Performance-focused, great for Next.js/React projects
Lerna	JavaScript	Works with npm/yarn workspaces for package management
Bazel	Multiple languages	Scalable for large enterprises like Google
pnpm Workspaces	JavaScript/TypeScript	Fast package management

Monorepos

Examples of Benefits

Code Sharing & Reusability
Simplified Dependency Management
Easier Refactoring
Improved CI/CD Pipelines
Stronger Collaboration & Visibility

Let's review the key benefits of Monorepos with some examples.

In monorepos, teams can easily reuse code across projects. Shared libraries (e.g., authentication, UI components) stay in sync without extra work. For example a React component library can be shared between the front end and an admin dashboard without publishing it as an npm package.

Since everything exists in one repository, dependencies remain consistent. If the back end and front end rely on the same API contracts, changes are synchronized.

With a monorepo, refactoring is safer. Developers can update all affected projects at once, avoiding breaking changes across repositories. For example, if the API changes from /v1/users to /v2/users, the front-end and back-end updates can be made in a single commit.

CI/CD systems (like GitHub Actions, GitLab CI, or Jenkins) can optimize workflows by running only the affected parts of the code. For example, if a developer updates only the front end, tests and deployments run only for the front end, not the entire stack.

Teams working on different aspects of the application (UI, API, DevOps) can see and contribute to changes in one place, improving teamwork.

Monorepos

Tools

✅ Use Monorepos When...	❌ Avoid Monorepos When...
You have multiple interconnected services	You have completely independent projects
Teams frequently share code/libraries	Teams work on separate, unrelated products
You need strict version control across projects	Your team prefers independent deployment cycles
You want a unified CI/CD pipeline	You have slow Git performance due to a large repo

TurboRepo and pnpm

Full Stack Development

Monorepos

Monorepos

Introduction

Monorepos

Example

Monorepos

Tools

Monorepos

Examples of Benefits

Monorepos

Tools