Complete Guide to .env Files for Configuration

Understanding .env Files

Environment files (.env) store configuration as key-value pairs.

Basic Syntax

# Database configuration
DATABASE_URL=postgresql://localhost:5432/mydb
DATABASE_POOL_SIZE=10
# API Keys
API_KEY=sk_live_abc123

Loading .env Files

Node.js:

require('dotenv').config();
const dbUrl = process.env.DATABASE_URL;

Multiple Environments

.env                 # Default/shared values
.env.local           # Local overrides (gitignored)
.env.development     # Development settings
.env.production      # Production settings