Multi-tenant shares infrastructure between customers (cheaper and easier to scale), but isolation and noisy-neighbor risks are harder. Single-tenant gives stronger isolation and simpler “per customer” limits, but costs more and is operationally heavier. Many systems use a hybrid approach.
Expanding on the short answer — what usually matters in practice:
A tiny example (an explanation template):
// Example: discuss trade-offs for "multi-tenant-vs-single-tenant-saas:-what's-the-t"
function explain() {
// Start from the core idea:
// Multi-tenant shares infrastructure between customers (cheaper and easier to scale), but is
}