eCommerce Architecture for Websites and Marketplaces: Definition, Examples, and Best Practices

Every ecommerce venture hinges on a robust online platform. However, what’s often overlooked is the underlying ecommerce architecture that supports and propels this platform. The right architectural foundation determines the future success of your business.

In this comprehensive guide, we explore the various ecommerce architectures that can drive your website, delve into the multiple layers that construct them, and provide invaluable insights into choosing the most effective model for your needs.

Whether you’re selecting a new vendor for an ecommerce project or considering replatforming to a more scalable solution, you'll find expert advice on how to approach this critical decision.

eCommerce architecture is an underlying foundation of an online ecommerce platform. It encompasses the platform’s architectural design, technical details, and components that facilitate selling and buying goods online. The term embraces everything, from the frontend user interface to the backend server infrastructure.

eCommerce architecture is the way all the technical components and structures are organized to provide the needed layers, subsystems, and components of an ecommerce platform and interact between them.

More often than not, when we talk about ecommerce architecture types, we think about the following components:

🔘 eCommerce architecture framework (e.g., two-layer, three-layer, five-layer) that represents architecture layers as a structural organization of an ecommerce system.

🔘 eCommerce architecture approach (e.g., monolithic, headless) that defines how all the components of a system interact and communicate with each other.

🔘 eCommerce architecture model (e.g., SaaS, PaaS) that defines how the system is deployed, implemented, and managed.

eCommerce architecture can be a unique combination of the different attributes described above. For example, a Software-as-a-Service (SaaS) ecommerce platform can be monolithic or headless, with a two-layer or three-layer structure that we will explain in detail further.

While ‘ecommerce architecture’ is a broader term, web-based commerce architecture refers specifically to ecommerce systems that operate through web technologies, typically hosted on the cloud or web servers. In other words, all web-based commerce architectures are ecommerce architectures, but not all ecommerce architectures are strictly web-based.

The idea behind a web-based commerce architecture is that such architecture is closely bonded with the web interface of the ecommerce website and can be split into two basic layers—client-side (frontend) and server-side (backend).

The common rule is that an ecommerce framework has at least two layers or tiers, the two essential components of an ecommerce software architecture—frontend and backend parts. However, such a simple architecture framework is somewhat outdated as it cannot support modern API-driven omnichannel capabilities. Today, a three-layer architecture framework is considered a basic standard for an ecommerce platform.

The three layers of an ecommerce architecture framework are as follows:

1. Presentation layer

This user-facing layer includes the website, layout, user interface, personal account portal, and any other part of the system end users can reach.

2. Application layer 

An application layer usually handles the business logic and all the internal processes, including product catalog management, shopping carts, payment processing systems, and order tools that make the system work.

3. Data layer

At this tier, all the data related to the ecommerce platform is stored. It includes product information, customer data, order history, and other details the system may need. 

While a three-layer framework is used in the majority of monolithic and SaaS platforms, the most advanced ecommerce solutions usually utilize a five-layer framework in ecommerce platforms.

To put it simply, the five-layer framework is more modular, separating UI, business logic, data, integration, and infrastructure. We use the example of Virto’s Commerce Innovation Platform architecture to describe each layer.

This layer consists of all frontend applications that interact with end users—such as websites, mobile apps, customer portals, and IoT interfaces. It doesn’t contain business logic or unnecessary backend data, ensuring a lightweight, flexible, and customizable frontend that can adapt to unique business needs.

This level contains business logic and processes requests from the frontend, controls commerce modules, and organizes data and integrations. Structured into independent logic blocks for different industries, it is accessible only to developers and serves as the foundation of ecommerce operations.

Built with the Atomic Architecture™ concept in mind, this layer consists of independent commerce modules with a separate block of features and capabilities that work for one particular goal (e.g., catalog module, pricing module, marketing module, inventory, and more). Ech of the modules is independent and linked to other modules and tiers through API. They can be seamlessly changed, upgraded, scaled up and down without affecting any other functionality.

While not part of the core ecommerce platform, these tools are critical for performance, scalability, and security. This layer includes essential infrastructure components such as databases (similar to the Data layer in an old-fashioned map, but wider), search modules, storage, cache, MySql tools, and more. The main part of the ecommerce system is connected to this tier via API, which means any of the modules can be easily replaced or exchanged.

This last layer plays a similar role for customers as a presentation layer. It uses API to connect the whole system to the user-visible interfaces (frontend), but this time, these aren’t the apps created by a system, but third-party apps connected to the ecommerce platform and necessary for its functioning. This includes CRMs, ERP systems, different payment systems, and more.

Now that we understand the ecommerce architecture framework better, let’s dive into the two main architecture models.

Monolithic architecture is a legacy approach where all components of a webstore are interconnected, causing any backend modifications to impact the entire solution. As a result, rebuilding the entire ecommerce system becomes the only way to implement any minor changes.

With a headless architecture approach, the frontend is completely decoupled from the backend logic. The communication between backend and frontend is facilitated through APIs. The headless approach enables true omnichannel commerce under a unified platform. It means that businesses can have multiple channels, devices, or frontends while maintaining consistent product presentation and user experience.

A Software-as-a-Service cloud model implies that a platform or software vendor takes over the deployment and maintenance of applications. This is the main reason why small to medium-sized businesses with limited resources choose a SaaS platform to deploy the solution quicker and reach the market faster.

The main difference between SaaS and PaaS platforms (and a major disadvantage of the former) is that SaaS solutions lack customization options to create tailored B2B business scenarios. The SaaS product’s backend is out of reach for platform users and can’t be modified. Take Google Workspace as an example: it is a great set of collaboration tools as is, but it can’t be modified to meet the unique needs of large enterprises. SaaS ecommerce solutions struggle to support complex B2B scenarios and force companies to adapt their business processes to fit platform functionalities.

A Platform-as-a-Service cloud model is somewhat similar to SaaS, but instead of delivering the software, PaaS provides a platform for software creation. This model implies that a platform vendor takes over the hurdles of deployment and software hosting but allows companies to customize and adjust the software for unique business needs. This approach decreases vendor dependency and offers companies more control over the software.

PaaS platforms are designed for headless commerce. In contrast to a SaaS model, leading PaaS platforms like Virto’s Commerce Innovation Platform allow users to make appropriate changes to the software backend. That means that in addition to taking advantage of regular centralized platform upgrades and new features presented by a vendor, enterprises can time- and cost-effectively test and implement unique customer features bypassing a platform vendor.

PaaS platforms offer extensive customization options, making them ideal for medium and large B2B enterprises seeking a future-proof solution that adapts to their business operations instead of requiring the business to conform to the platform.

On-prem implies the company, and not the platform vendor, is responsible for installing and hosting an ecommerce platform on a company’s hardware infrastructure.

The main misconception we see from B2B companies considering on-premises deployment is that they often assume that it is done simply by deploying a platform as is by following simple instructions provided by a vendor. However, modern B2B ecommerce solutions encompass numerous independent software to deliver tailored solutions for business needs. These can include specific search engine software, PIM solutions, CMS or CRM systems, and more.

When deploying on-premises, a company must consider all the software that must be installed independently from a platform and usually at a higher price compared to a packaged deal by a cloud-based platform vendor.

From our experience, on-prem deployment and data hosting is a viable option for very niche markets and companies under strict regulatory compliance requirements. The pharmaceutical and biotechnology industries are a great example of this. Due to very strict data privacy laws, pharma companies can require on-prem software that gives them full control over sensitive information and allows them to determine who and when has access to data.

Pros: 

1. Ready-to-use

Once you install a SaaS solution, you can use its out-of-the-box features right away.

2. Automatic centralized updates

The provider is responsible for centralized platform updates. However, it cannot adapt to your needs.

Cons:

1. Vendor-dependent

To maintain the software and ensure its availability, you need to fully rely on a provider, even if the provider fails to upgrade some parts or takes too long to implement changes.

2. Not adaptable

With a static SaaS platform license, you get a set of ready-to-use features that are the same for all users of this solution. Once you develop unique features, you will have to persuade your SaaS vendor that this feature is essential or simply go through an expensive replatforming.

3. Integration challenges

SaaS solutions can only integrate with the third-party tools they are initially built for. Integration with any other tools can become a real challenge.

Pros: 

1. Flexibility & Adaptability

Modular architecture of a PaaS solution allows for easy customization of both frontend and backend and integration with other systems and software, making it a flexible option for businesses.

2. Cost-effectiveness

Modern PaaS solutions are often order-based or GMV-based with transparent pricing principles. Adaptable PaaS solutions easily adapt to rapidly changing market conditions and business scenarios at predictable costs.

3. Easy integrations

Thanks to an API-first approach of PaaS platforms, every piece of business data and function is accessible via API. A PaaS platform can be integrated with any third-party solution, service, or functionality via API, ensuring smooth data transfer.

Limitations:

1. The complexity of the architecture

Modern ecommerce systems bring many opportunities for your business development and growth. While a PaaS solution requires a capable technical team to bring ideas and innovations to life, today’s leading PaaS platform vendors provide very strong support for complex projects. A platform vendor with an active developer community, comprehensive documentation, and a self-service knowledge base can often indicate much-needed proactive and responsive support.

2. Limited frontend theme variations

With a PaaS platform, businesses can kick-start with a ready-to-use frontend that supports white-labelling, branding, and several precomposed themes or styles. Creating a unique design can require additional development and customization efforts. In contrast, SaaS solutions can offer more precomposed themes but limit the ability to customize them to meet the unique needs of enterprises.

Virto Commerce offers a modern PaaS innovation platform that ensures fast time-to-value with maximum flexibility. The platform is cloud-native, API-first, headless, and adaptable. Here are the main reasons why a solution built on Virto’s Commerce Innovation Platform is the #1 choice for B2B enterprises:

☑️ Virto’s Extensibility Framework

With Atomic Architecture™ at its core, Virto’s Commerce Innovation Platform has a unique extensibility framework. It allows developers of any technical level (including business users, analysts, and QA specialists) to contribute and extend the platform—from quick prototyping and low- or no-code development to advanced-composed solution development.

☑️ Continuous Platform Updates

Customers of the Commerce Innovation Platform can immediately leverage new features and centralized improvements without worrying about compatibility issues, allowing their ecommerce operations to stay ahead of the curve.

☑️ Backend Available in 10 Languages

Virto Commerce Engine, a backend of the platform, is now available in 10 languages (English, German, French, Spanish, Portuguese, Polish, Italian, Chinese, Japanese, and Russian) and allows international teams to operate seamlessly.

☑️ Multi-Regional Support

On the customer side, the platform caters to multi -regional, -lingual, -currency settings, custom pipelines, compliance and verification methods, and permission assignments inherent to multi-vendor marketplaces.

☑️ Vendor-Funded Feature Development

Virto Commerce doesn’t just deliver software—the team actively invests in platform innovation and feature development at our own expense. If a customer needs a feature that could benefit others, the Virto Commerce team is ready to take on its development and fund it at the platform level. This means the feature gets built and tested without affecting the client’s implementation budget.

☑️ Open Contribution Policy

Virto Commerce embraces an open development model, allowing customer developer teams to independently build and contribute new features to Virto’s Commerce Innovation Platform. After internal review and approval, the Virto Commerce team integrates these contributions into the platform, taking full responsibility for their maintenance and support. This ensures that custom-built features and solutions become sustainable, backed by a platform vendor, without additional maintenance costs for the client.

Out of all the ecommerce architecture types, the most suitable architecture for modern large-scale ecommerce websites is a five-layered, headless, API-first PaaS model.

HEINEKEN, Bosch, Cadillac, De Klok Dranken, Standaard Boekhandel, and other world-known brands have already reached market superiority by replatforming to Virto’s Commerce Innovation Platform. To learn more about how Virto Commerce skyrockets business growth, download our updated Architectural Guidelines or reach out to our experts for a personal consultation.