Monolithic architecture structures an application as a single, unified codebase. All the components—including the user interface, business logic, and data access—are combined into one program that runs as a single process. This approach keeps everything tightly integrated and straightforward to manage.

Monolithic architecture is especially common in early-stage or small projects because it is simple to set up and deploy. You only need to manage one codebase and one deployment process, which can speed up development and reduce initial complexity. This makes it a practical choice when you are building a new application from scratch or working with a small team.

Main Advantages of Monolithic Architecture

• Simple deployment; you package the entire application into a single file or directory, making it easy to launch and manage;
• Shared codebase; all your code lives in one place, so it is easier to find, edit, and reuse functions or logic;
• Straightforward development; you can build, test, and run everything together without worrying about splitting features across services.

Limitations of Monolithic Architecture

• Scalability issues; it is hard to scale just one part of the application because every component runs together as a single unit;
• Tight coupling; different features and modules depend heavily on each other, so changes in one area can affect the whole system;
• Slower updates; any small update requires you to rebuild and redeploy the entire application, which slows down the release process.

Monolithic Architecture Diagram

A monolithic architecture is a single, unified application where all features and components are combined into one codebase and deployed as a single unit.

+------------------------------------------------+
|                Monolithic App                  |
|  +----------+  +-----------+  +-------------+ |
|  |  UI      |  | Business  |  |   Database  | |
|  | Layer    |  | Logic     |  |   Access    | |
|  +----------+  +-----------+  +-------------+ |
+------------------------------------------------+

All modules, such as the user interface, business logic, and database access, are tightly integrated and run together as one process.

Practical Example: Monolithic Architecture in a Startup

Suppose you are building an online bookstore as a startup. Your team is small, and you need to launch quickly with a basic set of features: user registration, book catalog, shopping cart, and order processing. In this situation, a monolithic architecture is appropriate because:

• All features can be developed and deployed together as a single application;
• You can manage the codebase easily with a small team;
• There are fewer operational complexities compared to managing multiple services;
• Deployments are simple, as you only need to update one application at a time.

A monolithic approach helps you focus on building and releasing your product quickly without worrying about the overhead of managing a distributed system. Later, as your bookstore grows and requires more scalability or independent feature updates, you can consider moving to a different architecture.