---
title: 'Backend folder structure'
---

```
├── scripts
├── e2e-test
└── src/
    ├── @types/
    │   ├── knex.d.ts
    │   └── fastify.d.ts
    ├── db/
    │   ├── migrations
    │   ├── schemas
    │   └── seed
    ├── lib/
    │   ├── fn
    │   ├── date
    │   └── config
    ├── queue
    ├── server/
    │   ├── routes/
    │   │   ├── v1
    │   │   └── v2
    │   ├── plugins
    │   └── config
    ├── services/
    │   ├── auth
    │   ├── org
    │   └── project/
    │       ├── project-service.ts
    │       ├── project-types.ts
    │       └── project-dal.ts
    └── ee/
        ├── routes
        └── services
```

### `backend/scripts` 
Contains reusable scripts for backend automation, like running migrations and generating SQL schemas.

### `backend/e2e-test` 
Integration tests for the APIs.

### `backend/src`
The source code of the backend.

- `@types`: Type definitions for libraries like Fastify and Knex.
- `db`: Knex.js configuration for the database, including migration, seed files, and SQL type schemas.
- `lib`: Stateless, reusable functions used across the codebase.
- `queue`: Infisical's queue system based on BullMQ.

### `src/server`

- Scope anything related to Fastify/service here.
- Includes routes, Fastify plugins, and server configurations.
- The routes folder contains various versions of routes separated into v1, v2, etc.

### `src/services`

- Handles the core business logic for all operations.
- Follows the co-location principle: related components should be kept together.
- Each service component typically contains:

  1. **dal**: Database Access Layer functions for database operations
  2. **service**: The service layer containing business logic.
  3. **type**: Type definitions used within the service component.
  4. **fns**: An optional component for sharing reusable functions related to the service.
  5. **queue**: An optional component for queue-specific logic, like `secret-queue.ts`.

### `src/ee`

Follows the same pattern as above, with the exception of a license change from MIT to Infisical Proprietary License.

### Guidelines and Best Practices

- All services are interconnected at `/src/server/routes/index.ts`, following the principle of simple dependency injection.
- Files should be named in dash-case.
- Avoid using classes in the codebase; opt for simple functions instead.
- All committed code must be properly linted using `npm run lint:fix` and type-checked with `npm run type:check`.
- Minimize shared logic between services as much as possible.
- Controllers within a router component should ideally call only one service layer, with exceptions for services like `audit-log` that require access to request object data.