# Environment Variables

> What guest code sees in process.env.

Guest code reads every host variable through `process.env`; writes are not passed to subprocesses.

## Variables Elide sets

| Variable | Value |
| --- | --- |
| `TMPDIR` | A per-run directory, removed on exit. `TMP` and `TEMP` on Windows. |
| `ELIDE_SYS_TMP` | The system temporary directory. `os.tmpdir()` returns it. |

Elide does not set `NODE_ENV`.

## Dotenv files

`.env` files load only through `process.loadEnvFile([path])`, which defaults to `.env` in the current directory.

## Security

`--allow-env[=NAMES]` sets which variables the `elide.pkl` manifest may read; it does not filter `process.env`.

Variables that configure Elide itself: [Runtime Environment Variables](https://elide.help/docs/runtime-env-variables).