- Multi-tenancy is a spectrum from fully shared to fully isolated, not a binary choice.
- Shared infrastructure is cheaper to operate but requires careful tenant data isolation.
- Enterprise customers sometimes require isolated infrastructure as a contractual requirement.
- The right model can differ by customer tier rather than being one-size-fits-all.
A spectrum, not a binary choice
Multi-tenancy ranges from a fully shared database with logical separation between tenants, to fully isolated infrastructure per customer, with several reasonable options in between. Treating it as a single yes/no decision oversimplifies what's actually a range of tradeoffs between cost and isolation.
Enterprise customers sometimes require isolation contractually
Larger enterprise customers, particularly in regulated industries, sometimes require dedicated, isolated infrastructure as an explicit contractual or compliance condition — a requirement that a purely shared architecture can't satisfy without a separate isolated offering for that tier.
Different tiers can use different models
A pragmatic approach some SaaS companies use is shared infrastructure for smaller customers, where the cost efficiency matters most, and isolated infrastructure available for enterprise customers willing to pay for it — rather than forcing every customer into the same architectural model.