MVC

MVC stands for Model–View–Controller. It is a way to organize an application by separating responsibilities into three parts.

        User
         ↓
    Controller
      ↙     ↘
 Model       View
  ↓           ↓
Database    User sees UI

1. Model

The Model handles the application’s data and business rules.

For example:

User
- id
- name
- email

It might communicate with the database:

Model → PostgreSQL

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2. View

The View is what the user sees.

For a web application:

HTML
CSS
UI components

For example:

┌─────────────────────┐
│ Welcome, Reyhaneh   │
│                     │
│ [ View Profile ]    │
└─────────────────────┘

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3. Controller

The Controller handles the request/action and coordinates the other parts.

For example:

GET /users/123

The controller might:

Request
  ↓
UserController
  ↓
UserModel
  ↓
Database
  ↓
UserController
  ↓
Response

Example:

async function getUser(req, res) {
    const user = await User.findById(req.params.id);
 
    res.json(user);
}

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In a backend application

You might have:

src/
├── controllers/
│   └── userController.js
├── models/
│   └── userModel.js
├── routes/
│   └── userRoutes.js
└── app.js

The flow could be:

HTTP Request
     ↓
   Route
     ↓
 Controller
     ↓
   Model
     ↓
 Database
     ↓
 Controller
     ↓
 HTTP Response

Important distinction

MVC is mainly about separation of responsibilities.

Instead of putting everything here:

app.get("/users/:id", async (req, res) => {
    // validation
    // business logic
    // database query
    // formatting response
    // ...
});

you separate those responsibilities into appropriate parts.

Also, MVC is an architectural pattern, not a requirement for REST APIs. You can build a REST API using MVC, but REST itself doesn’t require MVC.

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Back-End My-Journey-In-Codeless