SaaS Architecture Decisions You Will Live With

SaaS Architecture Decisions You Will Live With

A SaaS product is a business model expressed as software, and a few early technical decisions decide how easily it can grow, be secured and be sold. They are worth making deliberately, because reversing them later means migrating customers.

Tenancy

Separate database per customer gives the strongest isolation and the simplest reasoning about a single client, at the cost of migrations run many times. A shared schema with a customer identifier on every table is cheaper to run and harder to get wrong only if the filtering is enforced in one place, always. Hybrid arrangements are common: shared by default, separated for clients with particular requirements. Whatever is chosen, the rule that access never crosses tenants has to be structural, not remembered.

Provisioning

Decide how a customer comes into existence: who creates the account, what gets stood up, how long it takes, and what happens on the first day. Manual provisioning works for the first customers and becomes a silent tax; automation built too early is wasted effort. The middle path is a single provisioning path used by both the sales process and the sign-up flow.

Billing and entitlements

Features are gated by entitlements recorded in the system, not by plans hardcoded in the interface. When pricing changes, it should be a configuration change rather than a release. Usage metering, if the model needs it, must be recorded as events at the source rather than reconstructed later.

Security and data handling

Authentication, role-based access, audit logging and a clear answer to "which data belongs to whom" belong in the foundation. Backups, export and deletion paths are part of selling to businesses that ask about them before they sign.

How we approach it

SaaS development at Black Origin IT starts in discovery with the business model written down: who pays, for what, and how the product must behave as customers are added. From there it runs through planning, design, development, testing, deployment and support.

Building a SaaS product? Tell us about your project and we will map these decisions with you.