# NestJS Configuration

> Environment variables validation and ConfigModule setup.

- Skill: `majiayu000/nestjs-configuration` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds add majiayu000/nestjs-configuration`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/nestjs-configuration/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: AI & ML
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/majiayu000/nestjs-configuration

---


# NestJS Configuration Standards

## **Priority: P1 (OPERATIONAL)**

Environment configuration and validation patterns for NestJS applications.

## Setup

1. **Library**: Use `@nestjs/config`.
2. **Initialization**: Import `ConfigModule.forRoot({ isGlobal: true })` in `AppModule`.

## Validation

- **Mandatory**: Validate environment variables at startup.
- **Tool**: Use `joi` or a custom validation class.
- **Effect**: The app **must crash** immediately if a required env var (e.g., `DB_URL`) is missing.

```typescript
// app.module.ts
ConfigModule.forRoot({
  validationSchema: Joi.object({
    NODE_ENV: Joi.string()
      .valid('development', 'production')
      .default('development'),
    PORT: Joi.number().default(3000),
    DATABASE_URL: Joi.string().required(),
  }),
});
```

## Usage

- **Injection**: Inject `ConfigService` to access values.
- **Typing**: Avoid magic strings. Use a type-safe getter helper or a dedicated configuration object/interface.
- **Secrets**: Never commit `.env` files. Add `.env*` to `.gitignore`.