Environment Configuration

When to use this skill

• New Projects: Initial environment setup
• Multiple Environments: Separate dev, staging, production
• Team Collaboration: Share consistent environments

Instructions

Step 1: .env File Structure

.env.example (template):

# Application
NODE_ENV=development
PORT=3000
APP_URL=http://localhost:3000

# Database
DATABASE_URL=postgresql://user:password@localhost:5432/myapp
DATABASE_POOL_MIN=2
DATABASE_POOL_MAX=10

# Redis
REDIS_URL=redis://localhost:6379
REDIS_TTL=3600

# Authentication
JWT_ACCESS_SECRET=change-me-in-production-min-32-characters
JWT_REFRESH_SECRET=change-me-in-production-min-32-characters
JWT_ACCESS_EXPIRY=15m
JWT_REFRESH_EXPIRY=7d

# Email
SMTP_HOST=smtp.gmail.com
SMTP_PORT=587
SMTP_USER=[email protected]
SMTP_PASSWORD=your-app-password

# External APIs
STRIPE_SECRET_KEY=sk_test_xxx
STRIPE_PUBLISHABLE_KEY=pk_test_xxx
AWS_ACCESS_KEY_ID=AKIAXXXXXXXX
AWS_SECRET_ACCESS_KEY=xxxxxxxx
AWS_REGION=us-east-1
AWS_S3_BUCKET=myapp-uploads

# Monitoring
SENTRY_DSN=https://[email protected]/xxx
LOG_LEVEL=info

# Feature Flags
ENABLE_2FA=false
ENABLE_ANALYTICS=true

.env.local (per developer):

# Developer personal settings (add to .gitignore)
DATABASE_URL=postgresql://localhost:5432/myapp_dev
LOG_LEVEL=debug

.env.production:

NODE_ENV=production
PORT=8080
APP_URL=https://myapp.com

DATABASE_URL=${DATABASE_URL}  # Injected from environment variables
REDIS_URL=${REDIS_URL}

JWT_ACCESS_SECRET=${JWT_ACCESS_SECRET}
JWT_REFRESH_SECRET=${JWT_REFRESH_SECRET}

LOG_LEVEL=warn
ENABLE_2FA=true

Step 2: Type-Safe Environment Variables (TypeScript)

config/env.ts:

import { z } from 'zod';
import dotenv from 'dotenv';

// Load .env file
dotenv.config();

// Define schema
const envSchema = z.object({
  NODE_ENV: z.enum(['development', 'production', 'test']),
  PORT: z.coerce.number().default(3000),

  DATABASE_URL: z.string().url(),

  JWT_ACCESS_SECRET: z.string().min(32),
  JWT_REFRESH_SECRET: z.string().min(32),

  SMTP_HOST: z.string(),
  SMTP_PORT: z.coerce.number(),
  SMTP_USER: z.string().email(),
  SMTP_PASSWORD: z.string(),

  STRIPE_SECRET_KEY: z.string().startsWith('sk_'),

  LOG_LEVEL: z.enum(['error', 'warn', 'info', 'debug']).default('info'),
});

// Validate and export
export const env = envSchema.parse(process.env);

// Usage:
// import { env } from './config/env';
// console.log(env.DATABASE_URL); // Type-safe!

Error Handling:

try {
  const env = envSchema.parse(process.env);
} catch (error) {
  if (error instanceof z.ZodError) {
    console.error('❌ Invalid environment variables:');
    error.errors.forEach((err) => {
      console.error(`  - ${err.path.join('.')}: ${err.message}`);
    });
    process.exit(1);
  }
}

Step 3: Per-Environment Config Files

config/index.ts:

interface Config {
  env: string;
  port: number;
  database: {
    url: string;
    pool: { min: number; max: number };
  };
  jwt: {
    accessSecret: string;
    refreshSecret: string;
    accessExpiry: string;
    refreshExpiry: string;
  };
  features: {
    enable2FA: boolean;
    enableAnalytics: boolean;
  };
}

const config: Config = {
  env: process.env.NODE_ENV || 'development',
  port: parseInt(process.env.PORT || '3000'),

  database: {
    url: process.env.DATABASE_URL!,
    pool: {
      min