❓Ever wondered how YouTube manages such a massive codebase?

When we think about building something like , the first question that comes is:

👉 “Do they keep everything in one project or split it into many?”

The answer is interesting.


🧠 Monorepo Concept (Simple Understanding)

A monorepo means keeping multiple projects or services inside a single repository.

So instead of having:

- one repo for frontend
- one repo for backend
- one repo for ML

Everything lives in one place.


🏗️ How It Looks (Simplified)

Imagine a structure like this:

youtube-monorepo/
│
├── frontend/
├── backend/
├── services/
│   ├── auth-service/
│   ├── video-service/
│   ├── recommendation-service/
│
├── shared/
├── infra/

Each folder is like its own mini project, but all are connected under one repo.


⚙️ Why Companies Use Monorepo

✅ 1. Easy Collaboration
All teams work in the same codebase.
No confusion about versions or dependencies.

✅ 2. Shared Code
Common utilities (like authentication logic, validation, configs) can be reused easily.

✅ 3. Consistency
Same coding standards, same tools, same structure across all services.

✅ 4. Easier Refactoring
If you change something globally, you can update everything in one place.


🔗 How Things Work Together

Even though everything is in one repo:

- Frontend still talks to backend via APIs
- Backend is still split into multiple services
- Each service can use different languages

👉 Monorepo is about code organization, not about merging everything into one app.


⚠️ But Is It Always Good?

Not always.

❌ Challenges:

- Repo can become very large
- Build times can increase
- Requires strong tooling and discipline

That’s why companies use advanced tools like:


💡 Reality Check

Companies like YouTube use a modified version of monorepo with strong tooling, not a simple GitHub repo.

👉 It’s not just about storing code together
👉 It’s about managing complexity at scale


🚀 Final Thought

Monorepo is not about making things simple.
It’s about making large systems manageable.

If you're building small projects, you don’t need this yet.
But understanding it early gives you a big advantage.