Service Architecture Conventions

Every service is three layers, one direction: server.ts → handlers/ → adapters/. Apply while writing, not after.

Versioning

• All routes live under /api/v1/. New endpoints are versioned from the first line. No unversioned routes "for now."

server.ts is thin

• server.ts defines routes and delegates. Nothing else.
• No business logic in server.ts or in a route definition. A route wires the request to a handler and returns its result.

handlers/ hold the logic

• Business logic lives in handlers/, one file per domain.
• A handler owns its domain's rules and orchestration. It calls adapters for anything external. It does not reach outside the process itself.

adapters/ wrap everything external

• Database, external APIs, queues, anything outside the process goes through an adapter in adapters/. Handlers never touch them directly.
• The database adapter uses StrictDB when it's installed, otherwise the native driver. Never Mongoose. A handler that imports a driver or calls an external API inline is wrong, that belongs in an adapter. The data adapter is the one place driver code lives, which is also where the mongodb-rules apply.

Service (package) separation

• A service owns its domain and is reached through its interface. A package does not reach into another package's internals or its data. Call the owning service.
• Code two services both need is hoisted to a shared layer, never imported sideways from a sibling.

The test: routes in server.ts read request-in, handler-call, response-out. Logic sits in handlers/. Anything that leaves the process goes through adapters/, and the data adapter uses StrictDB if installed, the native driver otherwise.