Cloud Computing Architectures

A merchant choosing a hosting plan is also choosing a cloud architecture, even if the sales page never uses that word. The architecture decides how a store’s servers are arranged, who controls them, and how the store behaves when things go wrong. This post covers the main architecture types used in ecommerce, what each one actually looks like day to day, and where a merchant tends to run into them.

Public Cloud

Public cloud means a store runs on shared infrastructure owned by a provider like AWS, Google Cloud, or Azure, alongside thousands of other customers.

Shopify and BigCommerce both run on public cloud infrastructure behind the scenes, which is why neither platform asks a merchant to think about servers at all. A self-hosted WooCommerce store on a host like Cloudways or Kinsta also sits on public cloud, just with a managed layer on top handling the setup. The resources are shared, but each store’s data stays separate, and the provider adds capacity automatically as traffic grows. For most small and mid-sized merchants, this is the default setup, since it costs less than owning dedicated hardware and scales without extra planning.

Private Cloud

Private cloud means the infrastructure is reserved for one company, either on hardware it owns or on a dedicated slice of a provider’s data center.

This setup shows up mostly with large retailers who have specific data handling rules, like a company storing payment data in a way that goes beyond standard PCI compliance, or a retailer with contractual requirements about where customer data physically sits. Private cloud costs more than public cloud because none of the hardware is shared, and someone still has to manage it. A small ecommerce store rarely needs this. It becomes relevant once a business has legal, security, or compliance requirements that public cloud can’t meet on its own.

Hybrid Cloud

Hybrid cloud combines public and private infrastructure, with different parts of the business running on each.

A retailer might keep its core storefront on public cloud for everyday traffic, while running its financial systems or customer database on private infrastructure with stricter access controls. The two environments connect, but they’re managed separately, which means a change on one side doesn’t automatically affect the other. This setup fits a business that has grown past a single cloud environment but still has specific systems it doesn’t want mixed in with general storefront traffic. It’s more common in retail chains with both an online store and older in-house systems than in a store built from scratch.

Multi-Cloud

Multi-cloud means a business uses more than one public cloud provider at the same time, rather than relying on a single one for everything.

A store might host its main site on Google Cloud but store backups on AWS, or run its email marketing platform on a provider that sits on Azure while everything else runs elsewhere. The reasoning is usually risk reduction: if one provider has an outage, not everything goes down at once. Multi-cloud adds real complexity, since each provider has its own tools, pricing, and setup process, so it tends to show up in larger operations with a dedicated technical team rather than in a single-store business.

Serverless and Composable Architecture

Serverless architecture runs code only when it’s needed, without a merchant renting a server that sits idle between requests. Composable, or headless, architecture separates the storefront design from the backend commerce system entirely.

A checkout function built with serverless computing only uses resources during an actual purchase, not while the store is sitting quiet overnight. Composable setups take this further: a brand might use Shopify’s backend to handle orders and inventory, while building a custom front end in React that calls Shopify’s API for data. This gives more control over design and page speed than a standard theme allows, at the cost of needing developers who can build and maintain that connection. Nike and other larger brands use this approach specifically to cut load times and customize the shopping experience beyond what a template supports.

Choosing the Right Architecture

Most merchants don’t choose an architecture directly. They choose a platform, and the platform comes with an architecture attached. A store on Shopify or BigCommerce is on public cloud by default, with no decision required. The choice becomes real once a business considers a self-hosted platform, adds a second cloud provider for backups, or wants a custom front end connected to its commerce backend. At that point, the right setup depends on what problem it’s solving: cost control points toward public cloud, compliance points toward private or hybrid, redundancy points toward multi-cloud, and speed or design control points toward composable.

Takeaway

Cloud architecture isn’t a single decision made once. It’s a layer that sits under every other choice a merchant makes about hosting, platform, and design. Public cloud covers most stores without any extra thought. Private and hybrid setups solve specific compliance or legacy problems. Multi-cloud protects against outages at the cost of added complexity. Composable architecture trades simplicity for control over speed and design. Knowing which one a store is actually running on makes it easier to tell whether a performance or cost problem comes from the architecture itself or from something built on top of it.