.env.development May 2026

Environment variables are always strings. This fails:

if (process.env.ENABLE_FEATURE) // "false" is truthy!

Do this instead:

const isEnabled = process.env.ENABLE_FEATURE === 'true';

In Node.js, process.env is mutated at startup. If you change .env.development while the server is running, the app won't see the changes. Always restart your dev server after editing environment files. .env.development

New developers joining a team should clone the repo and run npm start without fighting database connections. A well-tuned .env.development provides sane defaults (e.g., a local SQLite database vs. a cloud PostgreSQL instance). Environment variables are always strings

Most modern frameworks (React with Vite, Next.js, Vue, Node.js with dotenv, Django, Laravel, etc.) support the following file precedence: Do this instead: const isEnabled = process