INTRO
Multi-tenant MongoDB mistakes are expensive: missing `tenantId` on a query is a data leak. This is how I keep isolation boring and enforceable — complementary to QuikPOS-style product lessons.
Indexes that match access patterns
Compound indexes starting with `tenantId` then time or status fields. Unbounded arrays per tenant still hurt — see operational schema notes.
Test with multiple tenants in staging; single-tenant demos hide scan bugs.
When DB-per-tenant appears
Strict isolation, noisy neighbors, or enterprise contracts can justify heavier tenancy. It raises ops cost — do not choose it for aesthetics.
Document the model in handover so the next engineer does not “simplify” into a leak.
KEY TAKEAWAYS
“tenantId on every read/write path.”
- 02
Compound indexes with tenant first.
- 03
Staging must include multiple tenants.
CONCLUSION
Closing thought
Designing tenancy for a Mongo SaaS? Bring your schema sketch to Contact for a review before you paint UI.
CONTINUE
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