Monolithic Architecture: Diagram, Components, and Working

Monolithic architecture is one of the oldest and most commonly used approaches to building software applications. It is well known for its simplicity, as it allows all the parts of the application to be developed and deployed as a single unit. It works well for small projects, but can become complex as the application scales. In this blog, let us explore monolithic architecture. Its features, components, and working process in detail

Table of Contents:

• What Is Monolithic Architecture?
• How Does Monolithic Architecture Work?
• Key Characteristics of Monolithic Architecture
• Key Components of Monolithic Systems
• Advantages and Disadvantages of Monolithic Architecture
• Deployment and Scaling in Monolithic Architecture
• Use Cases of Monolithic Architecture
• When to Choose Monolithic Architecture
• Challenges in Monolithic Architecture
• Best Practices for Monolithic Development
• Conclusion

What Is Monolithic Architecture?

Monolithic architecture means your whole application is developed and deployed as a single unit. All of the features, functions, and components of the app are built together in a single codebase. This structure is like a big building because everything happens under one roof.

Monolithic Architecture Example: Let’s say you have a programming platform. In a monolithic architecture, the Edtech dashboard, courses library, shopping cart, payment, and progress tracker are built together in one file or one application. If you want to change the payment system, you could possibly change and redeploy the entire app.

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How Does Monolithic Architecture Work?

Monolithic architecture is an approach where all the parts of an application are created and executed together as one big program. The front-end (user interface), back-end (logic), and database access are all tightly coupled and packaged together. When you have to make changes, you have to update the whole application, not just a small part, because all parts are dependent on each other

Monolithic Architecture Example: Let’s take an example of a mobile banking application where all features like login, balance of an account, transfer of money, and notification related to transactions are part of one big file, and if you just want to improve the money transfer feature, you still need to redeploy the entire application again.

Let’s explore the working process:

Step 1: Combined Coding for All Features

In a monolithic setup, all features are written together as a single project. Things like logging in, searching, and customer payment are just additional features added to a single project in the same codebase. If we need to add a new feature, or add to or change an existing feature, it is all done in one project.

Step 2: Building the Entire Codebase

Once everything is developed and all of our features are done, all of the code is compiled into one executable file (.exe, .jar, WAR, etc.) and deployed, which contains everything the app needs to run and perform its functions.

Step 3: Packaging Up to Deploy Whole Applications

The entire application is deployed to our server, including dependent code, database schemas, and other features. Individual features cannot be deployed independently.

Step 4: Each user interacts with a single application

Once the application is published (website, mobile app, etc.), users have access to some features in our application that have a structure running lots of functions, and our structure automates the process behind the scenes. 

Step 5: All Components Work Together

Interface, business logic, and database (or repositories) work together within the same application. When an end-user performs operations like a login, the functionality relies on method calls, not API calls with external services.

Step 6: Updates and Changes

If you want to change something (i.e., you have a bug to fix or new functionality), developers would go back into the codebase to make changes, rebuild everything, and then redeploy the entire application (or system) again.

Key Characteristics of Monolithic Architecture

• Single Codebase: All of the code is in one large file or project.
• Unified Deployment: The full app is deployed in a single action.
• Tightly Coupled: All modules are tightly connected and dependent.
• Shared Resources: Uses one database and shared libraries.
• Simple Communication: The modules communicate via internal method calls rather than external APIs.

Key Components of Monolithic Systems

A monolithic system will generally consist of the following components: 

• User Interface: The part of the application that the user can see or interact with.
• Business Logic Layer: This deals with the rules and procedures of the application, including calculations, decisions, and data processing.
• Data Access Layer: This is the connection from the app to the database, sending and retrieving data like customer data and lists of products.
• Database: This is where all of the application data is stored in one place. Most commonly, these are relational databases, such as MySQL or PostgreSQL. 

All of these components are part of the same software package, while working together very closely.

Monolithic Architecture Diagram

Advantages and Disadvantages of Monolithic Architecture

Monolithic Architecture has many benefits, especially when it is used for small teams and simple applications. But as your app grows, it comes with some disadvantages as well.

Advantages

1. Simple to Develop: It is easier to develop an app in a monolithic form. You don’t have to worry about splitting features or figuring out where to put separate services. 

2. Faster Development in the Beginning: All the code is together in one place, which makes it easier to test them together.

3. Simple Testing: Tests can be done over the whole app easily, just by running the test on the whole unit. 

4. Easy Deployment: You only have to deploy one package when you update your code, and the process is generally faster than microservices. 

5. Good Performance: These internal function calls (calls to functions within the same system) are generally quicker than external calls made in microservices. 

Disadvantages

1. Hard to Maintain: The application code will become large and difficult to maintain over time. Simply changing something small could force you to test the entire application. 

2. Not Scalable: You are unable to scale one feature at a time. You must scale the entire application, which includes more resource usage. 

3. Slow Deployment: Even a small bug fix requires you to rebuild and redeploy your entire application. 

4. Risk of Full Failure: If one of your components crashes, the entire application may fail since everything is tied together. 

5. Tight Coupling: Since all modules are tied together, a change in one part may impact another, which increases the risk of bugs.

Deployment and Scaling in Monolithic Architecture

In monolithic architecture, the deployment process is simple but not the most efficient, since the entire application is packaged and released as one unit. A small change like fixing a minor bug or adding a feature requires rebuilding and deploying an entire application. Thus, this can slow down the development for some teams as it may also introduce more errors during this deployment phase.

Scaling is also a major challenge for monolithic systems. It is impossible to scale one portion of the application that is under high demand, for example, a checkout process that is processing many more transactions than other services requires scaling the entire application. This leads to unnecessary and unwanted use of infrastructure (increased costs) for this scaling need. 

Use Cases of Monolithic Architecture

Let’s explore some real-world applications where this architecture is used:

• Simple or small applications: It can be used where the number of applications is limited and has less number of users.
• Startups or new projects: Monolithic architecture is suitable for startups and new team members, which helps to get the product ready quickly without worrying about initial setup.
• Single team development: If it is only one small team building the application, it is easier to coordinate the work inside a single code base.
• Internal tools: Many companies build internal software tools using a monolithic architecture since they have low user load and limited features.

When to Choose Monolithic Architecture

You should choose this architecture when:

1. You are creating a small or medium-sized application.
2. Your team is small, and communication is straightforward.
3. You are looking to build and launch rapidly.
4. You are early in a product’s life cycle.
5. You do not require updates that are used at different intervals or parts of your application.
6. You are looking for something cost-effective and less tool-wrangling.

Challenges in Monolithic Architecture

While building a monolithic application is relatively easy and comfortable at first, maintaining and managing it allows for several operational challenges as the application grows. These challenges can hamper your development speed, performance, and flexibility.

• Difficult to Maintain Large Codebase: When features are added, the code base becomes more complicated and larger. Therefore, developers can have difficulty maintaining or understanding the full code. A mistake in a particular line of code can affect the entire application.
• Slow Development over time: At first, development is fast. But as the app grows, it slows down due to the fact that every tiny bug fix or feature requires the developer to test and debug against the entire system.
• Difficult to Scale: Monolithic applications cannot scale other features individually. If the search feature or payment process requires more resources, you will have to scale the whole application, which becomes costly and inefficient.
• Risk of Total System Failure: Since the parts are closely coupled together, failure in any part of the application can affect the entire system. If the login system fails, the user cannot access the application. This negatively affects user experience and the reliability of the system as a whole.

Best Practices for Monolithic Development

1. Keep Your Code Organized: Maintain structure in your code using folders, modules, and naming conventions to keep your code readable and organized.

2. Follow the MVC Pattern: Model-View-Controller (MVC) helps separate business logic, data logic, and the logic for UI.

3. Think Reusability: Try to avoid writing duplicate code, and use functions and classes to make your code reusable.

4. Use Version Control: Version control tools like Git help in tracking the changes and make code manageable.

5. Automated Testing: Automate tests so that it is easier to detect bugs early without reviewing the code manually.

Conclusion

Monolithic architecture can be a good option for small and simple applications due to the easy setup process and fast development of the products. But as the application grows, it becomes harder to maintain, scale, and update. Initially starts with simplicity, but can become inflexible and slow down in the long term. Whether you choose monolithic or microservices will depend on the size of your project, your team, and what your future needs may be. Planning and following best practices are key to making sure that you have long-term success.

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Monolithic Architecture – FAQs