backend-standards

To enforce infrastructure and domain separation in a Node.js backend, apply the CMDO architecture pattern. It strictly defines boundaries for Operator, Config, Controller, Model, and DAL layers, ensuring domain logic remains isolated from infrastructure concerns.

The CMDO architecture pattern in TypeScript is a layered design standard separating backends into Config, Model, DAL, and Operator components. It enforces strict file structures, naming conventions, and one use-case per file to maintain clean backend architecture.

Structure Node.js entry points and telemetry by limiting bootstrapping to src/index.ts while making all other files pure exports. Initialize logging and OpenTelemetry metrics strictly within the Operator layer for centralized observability.

Yes, the CMDO standard requires lowercase_with_underscores file naming and prohibits DAL repositories. Controllers must assemble dependencies for Model use-cases and expose HTTP handlers, while vetted health checks run on a separate port.

The best way to refactor a Node.js backend to layered design is migrating files to CMDO boundaries. Reorganize logic into Operator, Config, Controller, Model, and DAL layers, enforcing one use-case per file and strict dependency controls.

You should not use strict layered architecture like CMDO for small prototypes or scripts where overhead outweighs maintainability benefits. The pattern enforces one use-case per file and explicit module boundaries, which requires significant upfront structural commitment.