Multi-tenant AI SaaS fails catastrophically if retrieval or tools leak across customers. Isolation, quotas, and boundaries are product requirements, not polish.
1. Data isolation checklist
- Every DB query scoped by tenant_id
- Vector search filtered by tenant before ranking
- Object storage prefixes per tenant
- No shared prompt cache across tenants for private content
2. Quotas and budgets
Map subscription plans to token credits or request caps. Check balance before calling the model. Soft warnings and hard stops both matter. Track spend per tenant and per feature.
3. Model and feature boundaries
Not every plan should get the most expensive model or agent tools. Gate capabilities behind plan flags. Keep audit logs of privileged actions.
4. Failure modes
If the provider is down, degrade gracefully. If a tenant hits quota, show upgrade paths, not silent failures. If retrieval returns empty, say so instead of hallucinating.
Summary
Multi-tenant AI is tenancy engineering plus LLM wiring. Isolation bugs are security incidents. Quotas protect margins.
Related: AI SaaS Development, RAG Development, Hire AI Developer.