What’s the Difference Between Monolithic and Microservices Architecture?

What's the difference between monolithic and microservices architecture?

A monolithic architecture is a traditional software development model that uses one code base to perform multiple business functions. All the software components in a monolithic system are interdependent due to the data exchange mechanisms within the system. It’s restrictive and time-consuming to modify monolithic architecture as small changes impact large areas of the code base. In contrast, microservices are an architectural approach that composes software into small independent components or services. Each service performs a single function and communicates with other services through a well-defined interface. Because they run independently, you can update, modify, deploy, or scale each service as required.

Read about microservices »

Key differences: monolithic vs. microservices

Monolithic applications typically consist of a client-side UI, a database, and a server-side application. Developers build all of these modules on a single code base.

On the other hand, in a distributed architecture, each microservice works to accomplish a single feature or business logic. Instead of exchanging data within the same code base, microservices communicate with an API.

Next, we discuss more differences between the two.

Read about APIs »

Development process

Monolithic applications are easier to start with, as not much up-front planning is required. You can get started and keep adding code modules as needed. However, the application can become complex and challenging to update or change over time.

A microservice architecture requires more planning and design before starting. Developers must identify different functions that can work independently and plan consistent APIs. However, the initial coordination makes code maintenance much more efficient. You can make changes and find bugs faster. Code reusability also increases over time.


Deploying monolithic applications is more straightforward than deploying microservices. Developers install the entire application code base and dependencies in a single environment. 

In contrast, deploying microservice-based applications is more complex, as each microservice is an independently deployable software package. Developers usually containerize microservices before deploying them. Containers package the code and related dependencies of the microservice for platform independence.

Read about containerization »


Debugging is a software process to identify coding errors that cause the application to behave erratically. When debugging monolith architecture, the developer can trace data movement or examine code behavior within the same programming environment. Meanwhile, identifying coding issues in a microservice architecture requires looking at multiple loosely coupled individual services. 

It can be more challenging to debug microservice applications because several developers might be responsible for many microservices. For instance, debugging may require coordinated tests, discussions, and feedback amongst team members, which takes more time and resources. 


A small change in one part of a monolithic application affects multiple software functions because of the tightly coupled coding. In addition, when developers introduce new changes to a monolithic application, they must retest and redeploy the entire system on the server.

In contrast, the microservices approach allows flexibility. It’s easier to make changes to the application. Instead of modifying all the services, developers only change specific functions. They can also deploy particular services independently. Such an approach is helpful in the continuous deployment workflow where developers make frequent small changes without affecting the system's stability. 


Monolithic applications face several challenges as they scale. The monolithic architecture contains all functionalities within a single code base, so the entire application must be scaled as requirements change. For example, if the application's performance degrades because the communication function experiences a traffic surge, you must increase the compute resources to accommodate the entire monolithic application. This results in resource wastage because not all parts of the application are at peak capacity.

Meanwhile, the microservices architecture supports distributed systems. Each software component receives its own computing resources in a distributed system. These resources can be scaled independently based on current capacities and predicted demands. So, for example, you can allocate more resources to a geographic location service instead of the whole system.

Operational impact: monolithic vs. microservices architecture

Microservices help you innovate faster, reduce risk, accelerate time to market, and decrease your total cost of ownership. Here’s a summary of operational benefits of microservice architecture.

Innovate faster

Monolithic architecture limits an organization's ability to introduce new business capabilities and technologies in existing applications. Developers cannot rebuild certain parts of the code base with new technological frameworks, which delays your organization in adopting modern technological trends.

Meanwhile, microservices are independent software components that developers can build with different frameworks and software technologies. The loose coupling between microservices allows businesses to innovate certain components more quickly. 

Reduce risks

Both monolithic and microservices applications experience code conflict, bugs, and unsuccessful updates. However, a monolithic application carries a more significant risk when developers release new updates, as the entire application presents a single point of failure. A minor error in the code base can cause the whole application to fail. Such incidents have the potential to cause severe service outages and affect all active users.

As such, developers prefer building microservices applications to mitigate deployment risks. If a microservice fails, other microservices remain operational, which limits the impact on the application. Developers also use tools to preempt and fix issues impacting microservices to improve the application's recoverability. 

Accelerate time to market

Software development effort for monolithic applications increases exponentially as code complexity grows. Eventually, developers have to spend more time to manage and cross-reference code files and libraries at the cost of building new features. When you develop with a rigid infrastructure, it creates delays to the anticipated timeline. 

Conversely, organizations with microservices expertise can build and release digital products faster. In a distributed software architecture, each developer focuses on a smaller chunk of code instead of a large one. When developers create a specific microservice, they don't need to understand how other microservices work. They only need to use the appropriate APIs, which are faster and easier to learn. 

Reduce total cost of ownership

Both microservices and monolithic applications incur expenses during development, deployment, and maintenance. However, the microservice approach is more cost-effective in the long term.

You can scale microservice applications horizontally by adding compute resources on demand. You only have to add resources for the individual service, not the entire application. To scale monolithic systems, companies must upgrade memory and processing power for the application as a whole, which is more expensive. 

Besides infrastructure costs, the expenses of maintaining monolithic applications also increase with evolving requirements. For example, sometimes developers must run legacy monolithic software on newer hardware. This requires custom knowledge, and developers must rebuild the application so that it remains operational. Meanwhile, microservices run independently of specific hardware and platforms, which saves organizations from costly upgrades.

When to use monolithic vs. microservices architecture

Both monolithic and microservices architecture help developers to build applications with different approaches. It's important to understand that microservices don't reduce the complexity of an application. Instead, the microservices structure reveals underlying complexities and allows developers to build, manage, and scale large applications more efficiently.

When you decide between developing a microservices or monolithic architecture, you can consider the following factors.

Application size

The monolithic approach is more suitable when designing a simple application or prototype. Because monolithic applications use a single code base and framework, developers can build the software without integrating multiple services. Microservice applications may require substantial time and design effort, which doesn't justify the cost and benefit of very small projects. 

Meanwhile, microservices architecture is better for building a complex system. It provides a robust programming foundation for your team and supports their ability to add more features flexibly. For example, Netflix uses AWS Lambda to scale its streaming infrastructure and save development time.

Read how Netflix uses Lambda »

Team competency

Despite its flexibility, developing with microservices requires a different knowledge set and design thinking. Unlike monolithic applications, microservices development needs an understanding of cloud architecture, APIs, containerization, and other expertise specific to modern cloud applications. Furthermore, troubleshooting microservices may be challenging for developers new to the distributed architecture. 


A monolithic application runs on a single server, but microservices applications benefit more from the cloud environment. While it's possible to run microservices from a single server, developers typically host microservices with cloud service providers to help ensure scalability, fault tolerance, and high availability.

You need the right infrastructure in place before you can start with microservices. You require more effort to set up the tools and workflow for microservices, but they are preferable for building a complex and scalable application.

How to transition from monolithic to microservices architecture

Migrating monolithic applications to a microservices architecture is possible but requires careful planning and implementation. It's important to pace the steps with consistent feedback from stakeholders. As a general guideline, you can follow these steps.

Make a plan

Develop a migration and deployment strategy that considers operational risks, customer experience, technological capabilities, timeline, and business objectives. 

Find a cloud partner

Partner with a reliable cloud provider and containerize the monolithic application. This is a necessary process that removes the application's dependency on specific hardware and software requirements. Then, your developers can start partitioning the large code base into several microservices. 

Adopt DevOps practices

Adopt the DevOps culture in your organization and use continuous integration and continuous deployment (CI/CD) tools to support the migration effort. DevOps is a software practice that allows a shorter development lifecycle with automation tools. 

Read about DevOps »

Build microservices

Build and deploy the microservices on the cloud infrastructure. Use appropriate tools to monitor the microservices health, traffic, and security and respond to issues promptly. If you’re interested, you can read a tutorial to break a monolithic application into microservices.

Summary of differences: monolithic vs. microservices


Monolithic architecture

Microservices architecture


Single code base with multiple interdependent functions.

Independent software components with autonomous functionality that communicate with each other using APIs.


Requires less planning at the start, but gets increasingly complex to understand and maintain.

Requires more planning and infrastructure at the start, but gets easier to manage and maintain over time.


Entire application deployed as a single entity.

Every microservice is an independent software entity that requires individual containerized deployment.


Trace the code path in the same environment.

Requires advanced debugging tools to trace the data exchange between multiple microservices.


Small changes introduce greater risks as they impact the entire code base.

You can modify individual microservices without impacting the entire application.


You have to scale the entire application, even if only certain functional areas experience an increase in demand.

You can scale individual microservices as required, which saves overall scaling costs. 


Low upfront investment at the cost of increased ongoing and maintenance efforts.

Additional time and cost investment to set up the required infrastructure and build team competency. However, long-term cost savings, maintenance, and adaptability.

How can AWS support your microservices architecture requirements?

You can build modern applications on Amazon Web Services (AWS) with modular architectural patterns, serverless operational models, and agile development processes. We offer a complete platform for building highly available microservices of any scope and scale.

For example, you can use these AWS services to set up and maintain a microservice architecture:

Get started with microservices on AWS by creating an AWS account today.