When a Modular Monolith Is the Right Starting Architecture
Why many products should earn distributed complexity instead of starting with it.
A modular monolith can be the right starting architecture when the product needs fast learning, strong domain boundaries, and simple operations more than independent service scaling.
The key word is modular. The codebase should separate domains, isolate business rules, define stable interfaces, and avoid shared database shortcuts that make future extraction painful.
Teams should consider services when there are clear reasons: independent scaling needs, different deployment ownership, hard security boundaries, or domain maturity that justifies the operational cost.
Starting simpler does not mean ignoring the future. Good observability, automated tests, clean module boundaries, and explicit contracts make later architecture decisions easier.