What is monolithic architecture (monolithic architecture)?

Monolith characteristics

The main feature of a monolith is its unified structure. All application code is usually contained in a single code base (codebase) and is built and deployed as a single artifact (e.g., WAR/JAR file in Java, .NET executable). Although internally the monolith may be divided into layers (e.g., presentation, logic, data layers) or modules, these divisions are logical, not physical – all parts operate within the same process.

Advantages of monolithic architecture

The monolithic approach has some advantages, especially for smaller and less complex applications:

• Simplicity of development (at the beginning): Getting started with a monolith is usually simpler. Everything is in one place, and developers can easily follow the flow of data and logic throughout the application.
• Easier deployment (initially): Deploying a single application is often simpler than managing the deployment of multiple independent services.
• Easier End-to-End Testing: Testing an entire application as a single entity can be simpler than testing interactions between multiple distributed services.
• Performance (in some cases): Intra-process communication (method calls) is usually faster than network communication between services.

Disadvantages and challenges of monolithic architecture

As the complexity and size of applications increase, the monolithic architecture begins to reveal its flaws:

• Scaling difficulties: Scaling a monolith typically requires replication of the entire application, even if only one part of it is heavily loaded. This is less cost- and resource-efficient than scaling individual services.
• Low fault tolerance: an error in one module can cause the entire application to fail.
• Development and maintenance problems: A large, monolithic code base becomes difficult to understand, modify and maintain. Changes to one part of the system can unexpectedly affect others. Time to build and deploy the entire application increases.
• Technology barriers: the entire application is usually built on a single technology stack. Introducing a new technology or programming language is difficult or impossible without rewriting much of the system.
• Difficulties in teamwork: Multiple teams working on one large code base can get in each other’s way, and the process of integrating changes becomes complicated.

Alternative: Microservices architecture

In response to the challenges of monoliths, microservices architecture, which involves dividing applications into small, independent services, has gained popularity. However, the choice between monolith and microservices depends on the specific case – for smaller projects or early stage development, a well-designed monolith may still be the right choice.

Summary

Monolithic architecture is the traditional approach to building applications as a single, cohesive whole. While simple at first, as the system grows in scale and complexity, it can lead to problems with scalability, maintenance, technological flexibility and teamwork. Understanding its advantages and disadvantages is crucial when making architectural decisions.