Platform Architecture

SaaS Commerce

SaaS commerce (Software-as-a-Service ecommerce) refers to platforms that host your store on their own infrastructure, handle platform maintenance and security, and charge you a monthly subscription fee for access. Shopify, BigCommerce, Wix Commerce, and Squarespace Commerce are all SaaS platforms.

The defining characteristic is ownership versus tenancy. On a SaaS platform, you’re renting a storefront. You don’t own the server, the software, or the checkout infrastructure. The platform does — and they’re responsible for keeping it running, secure, and compliant with payment-card industry standards (PCI DSS).

What SaaS commerce gives you

  • Managed infrastructure: No server administration, no PHP version conflicts, no security patching. The platform handles it.
  • Hosted checkout: PCI-compliant payment processing built in. You don’t need to build or maintain a secure checkout; you use the platform’s.
  • Automatic updates: Platform improvements deploy without you initiating anything. A new Shopify feature appears in your admin after the platform update, not after you run a plugin update.
  • Guaranteed uptime SLAs: Shopify’s 99.98% uptime SLA means Black Friday traffic spikes are the platform’s problem to absorb, not yours.

The cost of tenancy

SaaS commerce costs more in ongoing fees than self-hosted alternatives — but it eliminates the maintenance overhead that self-hosted platforms (WooCommerce, Magento) require.

PlatformMonthly SaaS feeWhat you avoid vs self-hosted
Shopify Basic$39/mo~£800–£1,500/yr in hosting + maintenance
BigCommerce Standard$39/mo~£800–£1,500/yr in hosting + maintenance
Wix Commerce Business$29/mo~£500–£1,200/yr in hosting + maintenance
Squarespace Basic Commerce$27/mo~£500–£1,200/yr in hosting + maintenance

The SaaS premium is real. So is the maintenance burden it eliminates.

SaaS commerce vs self-hosted — choosing

The decision framework is simple:

  • Developer access available? Self-hosted (WooCommerce, Magento) is cost-competitive once you account for maintenance.
  • No developer access? SaaS eliminates entire categories of risk — plugin conflicts, security incidents, server-level performance issues — that self-hosted requires active management to prevent.
  • Need full customisation control? Self-hosted is the only option.
  • Need to launch quickly? SaaS wins on setup speed.

See also: Self-hosted commerce · Headless commerce · Hosted checkout · Shopify review · BigCommerce review