Node.js: how do I read environment variables from a .env file?

Question

`process.env.DATABASE_URL` is `undefined` even though it's in my `.env` file. Do I still need the `dotenv` package?

Accepted Answer

Node doesn't read `.env` automatically. Since Node 20.6 you have a built-in flag, so you no longer need `dotenv`:

```bash
node --env-file=.env server.js
# optional file, no error if missing (Node 22+)
node --env-file-if-exists=.env server.js
```

Or in code (Node 21.7+): `process.loadEnvFile()`.

On older Node versions, `import 'dotenv/config'` at the very top of your entry file still works.

Don't forget: add `.env` to `.gitignore` and commit a `.env.example` with placeholder values.

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