Monorepo in GitHub

Introduction

Have you ever worked on multiple projects and thought:

“Why am I managing 5 different repositories for things that are connected?”

That’s exactly the problem a monorepo solves.

Companies like Google, Facebook (Meta), and Microsoft use monorepos to manage massive codebases efficiently.

In this article, you’ll learn:

• What a monorepo is
• Why developers use it
• How to create one in GitHub
• Real-world examples
• Pros & cons

What is a Monorepo?

A monorepo (monolithic repository) is:

A single GitHub repository that contains multiple projects.

🆚 Traditional Approach (Multi-repo)

project-frontend/
project-backend/
project-mobile/

Each project = separate repo

✅ Monorepo Approach

my-app/
 ├── frontend/
 ├── backend/
 ├── mobile/
 └── shared/

Everything = ONE repo

🤔 Why Use a Monorepo?

1. 🔄 Easier Code Sharing

Instead of copying code between repos:

shared/
  └── utils.js

All projects can reuse it.

2. 🚀 Atomic Changes

You can update frontend + backend in one commit.

Example:

• Update API
• Update UI
• Push together ✅

3. 🧩 Better Collaboration

No version mismatch issues between repos.

4. 📦 Centralized Dependency Management

Tools like:

• npm
• Yarn
• pnpm

help manage dependencies in one place.

🛠️ How to Create a Monorepo in GitHub

Step 1: Create a Repo

Go to GitHub → Create new repository

Step 2: Structure Your Project

my-monorepo/
 ├── apps/
 │    ├── frontend/
 │    └── backend/
 ├── packages/
 │    └── shared/
 ├── package.json
 └── README.md

Step 3: Use Workspaces (Important!)

Example using npm workspaces:

{
  "name": "my-monorepo",
  "private": true,
  "workspaces": [
    "apps/*",
    "packages/*"
  ]

Step 4: Install Dependencies

npm install

⚡ Popular Monorepo Tools

• Nx → powerful for large apps
• Turborepo → fast builds (by Vercel)
• Lerna → classic monorepo manager

🌍 Real-World Example

Imagine you’re building:

• Web App (React)
• Mobile App (React Native)
• Backend API (Node.js)

Instead of 3 repos:

👉 Put everything in ONE monorepo and share:

• UI components
• API types
• Utility functions

⚠️ Monorepo — Pros & Cons

✅ Pros

• Easier code sharing
• Single source of truth
• Simplified versioning
• Better team collaboration

❌ Cons

• Repo can get VERY large
• Slower CI/CD if not optimized
• Requires proper structure

🧠 When Should You Use It?

Use monorepo if:

• Projects are closely related
• You share code frequently
• You want tight integration

Avoid if:

• Projects are completely independent
• Teams are totally separate