Monolithic vs. Microservices Architecture: Which Is the Best for the Modern eCommerce Business?

Any modern eCommerce business sooner or later faces a crucial decision for their development strategy: Should their software use monolithic or microservices architecture at its core? This foundational choice eventually shapes how businesses build, run, and scale their online platforms, influencing virtually every aspect of digital operations. Each approach offers distinct benefits and challenges from both a developer’s and a business’s perspective. 

The choice between monolithic and microservices architectures isn’t just a technical decision—it’s more of a strategic choice, just like in the case of selecting a reliable front-end development services provider. In practice, this architectural choice shapes a company’s capacity to evolve, adapt to shifting markets, and stay ahead of rivals. 

So what do we have? On the one hand, we have monoliths, unified systems that can streamline early development and oversight. On the other hand, we have microservices that break operations into smaller, independent components, providing flexibility to grow. But what do these architectural solutions mean in practice? What is the difference between monolithic and microservices architectures? How do these architectures impact scalability, development speed, and maintenance, in real-world eCommerce scenarios? To truly understand the implications of this architectural decision, let’s explore these questions together!

What is monolithic architecture?

Let’s begin with the all-in-one approach of monolithic architecture. This system design makes the software function as a single yet cohesive unit. Every component—whether handling purchases or processing payments—operates in sync within a single integrated system. Elements within this system share common code, data storage, and assets. Essentially, the monolithic approach involves building, deploying, and scaling the entire application as one entity.

In a typical monolith-based eCommerce application, changes in code in one part of the system affect the entire system. While this factor can simplify initial development and testing, it may pose challenges as the platform grows. Besides this, in a monolithic setup, scaling specific functions independently is difficult and updates often require redeploying the entire application. Speaking in general terms, this architecture suits smaller businesses or those with stable, predictable growth patterns.

Here is a diagram illustrating a simple example of monolithic architecture.

Monolith architecture for eCommerce business

As mentioned earlier, in eCommerce, a monolithic architecture typically integrates all core functions—product catalog, shopping cart, payment processing, and order management—into a single, tightly-knit system. This unified approach contrasts sharply with microservices, where each function operates independently. For online stores, especially smaller ones or those just starting out, monoliths offer a straightforward path to launching a complete platform that has everything you need to start your operations.

The monolithic structure reflects the very interconnected nature of online shopping. Every customer interaction, from browsing products to completing a purchase, flows through a single, unified system. In some ways, it mirrors the traditional in-store experience, where all departments work together seamlessly. For instance, when a customer adds an item to their cart, the monolith simultaneously updates inventory, prepares shipping calculations, and adjusts promotional offers—all within the same code base.

Monolithic architecture pros

• Simplified development: A single code base makes it easier for developers to build and maintain the software system;
• Faster initial deployment: The all-in-one nature of the monolithic approach allows for quicker setup of a complete eCommerce platform;
• Easier testing: Integrated components enable more straightforward end-to-end testing processes;
• Lower initial costs due to a streamlined development process;
• Streamlined performance: Tightly coupled components often lead to faster response times in simpler systems;
• Unified data model: A single database simplifies data management and reduces redundancy.

Monolithic architecture cons

• Limited scalability: In monolithic applications, the entire system must be scaled together, even if only one particular component needs additional resources;
• Difficult updates: Changes to one part of the system can affect the whole, making updates riskier;
• Technology lock-in: Switching to new frameworks or technologies be it backend or frontend technologies becomes challenging once the system is established;
• Slower innovation: The interconnected nature of monolithic applications can significantly slow down the implementation of new features;
• Reduced flexibility: However, it’s not only about new software features. Adapting to changing market needs or integrating new third-party tools can also be cumbersome in the monolithic ecosystem;
• Harder to understand: As the system grows, the code base can become complex and difficult for new developers to grasp;
• Single point of failure: Issues in one part of the system can potentially bring down the entire platform, stopping all your business operations.

Examples of monolithic architectures

Let’s check how monolithic architecture works in practice.

Shopify

Shopify, a giant of eCommerce, embraces a “Majestic Monolith” approach for its core platform, using a single application to handle most user-facing functions. Although their architecture is internally organized into components focused on different business domains (it’s often called a modular monolith, which we will return to a bit later), their particular case still shares more similarities with typical monolithic structures. Considering that Shopify’s code base consists of more than 2.8 million lines of code, some level of modularization is expected anyway.

Despite handling massive traffic during events like Black Friday, Shopify’s architecture remains robust due to the pragmatic use of common technologies like MySQL, Redis, and Elasticsearch, scaled horizontally. The company’s focus on simplicity and expert management of key components enables the monolith to scale effectively, challenging the notion that microservices are the only way for high-performance eCommerce platforms.

Amazon

You’ve probably heard about the monolith to microservices stories. However, Amazon’s story is slightly more complicated. In some sense, Amazon’s architectural journey reflects the history of software design itself. Initially, they used a monolithic structure, but at some point, like many other eCommerce companies, they shifted to microservices to increase flexibility and speed up the development process. However, this approach led to unexpected challenges, particularly for Amazon Prime Video’s quality analysis tool. The microservices design, while theoretically scalable, proved costly and led to performance bottlenecks.

In a surprising move, Amazon’s Prime Video team recently reverted to a monolithic architecture for their video monitoring tool. This decision was driven by the two basic needs mentioned above. By moving to the monolithic structure, they reduced costs and improved efficiency; by consolidating their system, they eliminated the overhead of multiple network calls and data transfers between microservices. The result of returning to monolithic software was impressive: a 90% reduction in their monthly AWS bill and improved performance. This shift demonstrates that architectural choices should be based on specific needs rather than following trends and that at times, simpler solutions can be more effective for certain tasks.

What is microservices architecture?

Microservices architecture breaks down an application into small, independent services, each focused on a specific business function. Unlike monoliths, where all components are tightly integrated, microservices operate autonomously and communicate through APIs. Each service typically has its own database and can be developed, deployed, and scaled separately. This approach allows teams to work on different parts of the application simultaneously, using various technologies as needed. While microservices offer flexibility and better scalability for specific functions, they also introduce complexity in managing multiple services and their interactions. 

Here’s what a simplest application looks like.

Microservices architecture for eCommerce businesses

Microservices architecture in the eCommerce industry divides the online store into separate, independent components. Each function—product catalog, shopping cart, payment processing, order management—operates as its own service. APIs maintain communication between services, allowing them to work together while remaining autonomous. For instance, when a customer adds an item to their cart, the cart service interacts with the inventory service to check the current stock level, and then with the pricing service for current rates. This structure allows eCommerce businesses to update or scale specific parts of their platforms without affecting the entire system, potentially speeding up new feature rollouts and adaptations to market changes.

Here’s an example of a microservices approach in a simple eCommerce application:

Microservices architecture pros

• Scalability: Individual services can be scaled independently. This allows for efficient resource allocation, especially during peak shopping seasons or flash sales;
• Flexibility in technologies: Different technologies can be used for different services, allowing the use of the best tool for each job;
• Faster updates: Individual services can be updated or replaced without affecting the entire system. New features or improvements can be rolled out quickly, helping keep the store competitive;
• Fault tolerance: If one service fails, it doesn’t necessarily bring down the entire platform due to fault isolation;
• Team autonomy: Development teams can work on different services simultaneously, increasing development speed;
• Easy integration: New features or third-party services can be added more easily as separate microservices if we compare monolithic architecture vs. microservices;
• Improved testing: Smaller, focused services are often easier to test comprehensively.

Microservices architecture cons 

• Complexity: Managing multiple services and their interactions can be more complicated than managing a monolithic system. This can make the entire system more difficult to understand and maintain, potentially leading to longer development cycles and increased training needs for new team members. 
• Data consistency: Keeping information in sync across multiple databases is tricky. Product details or customer data might not match up in different parts of the system, leading to confusion and errors;
• Network delays: Communication between services across a network can introduce latency, potentially impacting performance;
• Higher costs: Running and maintaining architecture with multiple services is typically way more expensive than using a single monolithic application;
• Debugging challenges: Troubleshooting issues across multiple services can be more difficult than in a monolithic system;
• Deployment complexity: Coordinating the deployment of multiple interdependent services requires sophisticated DevOps practices;
• Security concerns: With more services, there are more potential entry points for security threats. Protecting each service is crucial but time-consuming. 

Examples of microservices architecture

eBay

eBay adopted a microservices architecture back in 2011. This shift from monolithic to microservices transformed the entire platform. The change was driven by the need to accelerate decision-making and implementation of new features. By breaking their system into hundreds, if not thousands, of independent services, eBay overcame the bottleneck caused by their architecture review board. This new approach allowed faster reviews of individual services, rather than considering the impact of each change on the entire system. The result was shorter development cycles and more agile responses to market needs. Additionally, eBay created reusable modules for functions like marketing, product reviews, and search, which improved consistency across both web and mobile apps. Such a microservices standardization reduced duplicate work and simplified updates, allowing eBay to innovate faster and maintain a competitive edge.

Walmart Canada

Walmart Canada initially adopted the microservice architecture to solve critical performance issues during peak shopping events, according to Kevin Webber, who led the platform re-engineering. At that time, Walmart Canada’s outdated systems couldn’t handle 6 million pageviews per minute, leading to website crashes on Black Fridays. By adopting microservices architecture, Walmart achieved near-perfect availability and substantial business gains. The new system increased conversions by 20% overnight and mobile orders by 98% in a short period of time. It also eliminated downtime during major sales events and reduced operational costs by 40%. This shift allowed Walmart to utilize cheaper, more flexible hardware and better meet customer expectations. 

Comparing monolith and microservices for eCommerce

Let’s compare microservices vs. monolithic architecture in nuances:

Aspect	Monolith	Microservices
Cost	Lower initial setup and maintenance costs. Typically it becomes expensive to scale as the system grows.	Higher operational costs due to complex infrastructure. Offers more cost-effective scaling for specific functions.
Performance	Faster for small-scale operations. Can struggle with high traffic loads.	Better at handling peak loads. However, it may introduce latency due to service communication.
Security	Simpler to secure as a single unit. One vulnerability can compromise the entire monolith.	More entry points to protect. Allows for tailored security measures for each service.
Reliability	A single point of failure affects the whole system. Easier to monitor and maintain as one unit.	Failures in one service don’t stop others. Requires more complex monitoring across services.
Team structure	Works well with smaller, generalist teams. This can lead to slower development as the team grows.	Supports larger teams with specialized skills. Supports parallel development across services.
Development workflow	Simpler to develop and deploy initially. Becomes complex and slow as the application grows.	Enables faster, independent updates to services. Requires careful orchestration and integration testing.
Scalability	The entire application must scale together. Difficult to optimize resources for specific functions.	Easy to scale individual services as needed. Allows for more efficient use of resources.
Technology stack	Uses one technology for the entire platform. The monolithic architectural approach limits the ability to adopt new technologies.	Can use different tech for each service. Enables using the best tool for each job.
Time to market	Faster for small, simple applications. Slows down as the application becomes more complex.	Takes longer to set up initially. Enables quicker iterations and feature releases long-term.
Debugging	Easier to trace issues in a unified codebase. Can be overwhelming in large applications.	More challenging to troubleshoot issues across services. Allows for more focused debugging with each service.

Blending monolith and microservices: The hybrid approach

But what if we said that monolithic vs. microservices choice is rather a spectrum than an either/or dilemma? Indeed, several hybrid approaches blend monoliths and microservices. The most popular of these hybrid approaches in eCommerce are so-called modular monoliths. This approach keeps a single code base but divides it into distinct, separate modules for functions like order processing or inventory management. It offers the simplicity of monoliths with the flexibility of microservices by allowing teams to work on different parts of the system without the complexity of completely distributed services.

This hybrid architecture strikes a balance that pure monoliths or microservices might miss. It improves traditional monoliths by making the system easier to understand and change. At the same time, they avoid the operational challenges of full microservices setups. This middle ground lets eCommerce businesses evolve their systems step by step, transitioning to microservices only where needed. Hybrid approaches like modular monoliths may be a practical choice for companies that want more flexibility than a monolith but aren’t ready to handle the full range of transitional monolithic to microservices challenges.

How to choose between monoliths and microservices?

In fact, the microservices vs. monolithic debate often oversimplifies a complex reality. The article’s author researched real-world examples, and many systems labeled as “microservices” or “monoliths” didn’t fit neatly into these categories when examined closely. These discussions often get bogged down in definitions rather than addressing specific needs. The advantages of each approach depend heavily on the context, making broad generalizations unhelpful. So, in our opinion, it’s more productive to focus on the actual structure and requirements of a system instead of debating abstract concepts.

Due to this, choosing the right architecture heavily depends on your specific situation. Generally, monoliths work well for smaller teams and simpler applications that need quick development. Microservices are suited for larger and more complex systems that require independent scaling and frequent updates. A hybrid approach, such as modular monoliths can be a good middle ground, offering some benefits of both approaches. The best monolithic vs. microservices architecture choice always should balance factors like team size, system complexity, future growth plans, and more.

At ELITEX, we know that selecting the right architectural decision for your software solution may be quite a challenging task. That’s why our experts are always here to help you navigate this complex decision. Whether you’re looking for further advice regarding the architecture of your eCommerce platform or seeking a reliable partner with extensive eCommerce software development experience, don’t hesitate to contact ELITEX! The ELITEX team has vast expertise in building scalable and efficient eCommerce solutions using various architectural approaches. Let’s work together to create a system that exceeds your initial expectations!

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