BackendDatabasesHigh signal
Multi-Tenancy
Also written as Multi-Tenant, Tenant Isolation
One running system serving many customer organisations at once while keeping each one's data strictly separate — the basis of most B2B SaaS products.
Think of it like
An apartment block: shared building and plumbing, but each flat has its own lock.
Junior or senior?
A strong SaaS-backend signal.
Senior sounds like
Talks about the isolation model they chose (shared tables, separate schemas, separate databases), noisy neighbours, and how they prevented one customer seeing another's data.
Ask them
“How did you guarantee one customer could never see another customer's data?”