Glossary
Modular monolith
An application that ships as one unit but has clearly separated modules with real boundaries inside.
The modular monolith answers the experience that distributed systems carry their own cost: network failures, distributed transactions, operational effort per service. Draw the boundaries cleanly but deploy together, and you get clarity without that bill.
The practical benefit comes later: if a module really has to become its own service, the seam already exists. Going from module to service is short work. Going from tangle to service is a project.
How you notice it
- Boundaries need to be clear, operations simple.
- The team is too small for many services.
- A later split should stay possible.
Frequently asked
What keeps modules from leaking into each other?
A rule the build enforces. Discipline alone fails within a quarter. Import checks or module boundaries that fail the build are what make the difference between a modular monolith and a monolith with folders.